Joint Symposium on Food Science and Technology · Joint Symposium on Food Science and Technology...
Transcript of Joint Symposium on Food Science and Technology · Joint Symposium on Food Science and Technology...
Joint Symposium on Food Science and
Technology
Food Science and Technology
Programme, NUS
and
Food Quality and Design Group,
WUR
29th October 2014
Programme Schedule and
Abstracts Book
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 1
Table of contents
Programme outline pg. 3
Presentation 1: Volatile organic compounds synthetized by specific spoilage organisms as spoilage indicators of raw salmon fillets
pg. 5
Presentation 2: Detection of chemical adulterations in spices pg. 6
Presentation 3: Chemical and volatile composition of lychee wines fermented with three non-Saccharomyces yeast strains
pg. 7
Presentation 4: Processing of several tropical fruits: Understanding the effect on the sensory properties, texture and nutritional composition
pg. 8
Presentation 5: Influence of fatty acid composition and stereochemistry of triacylglycerols on physical properties of milk fat
pg. 9
Presentation 6: Frozen bread dough: Mathematical modelling and controller design pg. 10
Presentation 7: Bioactive properties of red sorghum bio-colorant and their derivatives pg. 11
Presentation 8: Organopolysulfides with potential H2S-releasing activity from shallot (Allium cepa L. Aggregatum Group) and stinky beans (Parkia speciosa)
pg. 12
Poster 1: Application of novel ingredients and technologies to nutritional powders - Effects on its physicochemical properties
pg. 14
Poster 2: Effect of intensely heated milk proteins on the development of immune tolerance to milk allergens
pg. 16
Poster 3: Authentication of edible bird’s nest using GC/MS pg. 17
Poster 4: Shortening the dry period of the dairy cow – influence on milk composition and quality
pg. 18
Poster 5: The impact of structural modifications of dracoflavan B on their alpha-amylase inhibition activity
pg. 19
Poster 6: Proteomic study of the dynamics in immune proteins between human milk and bovine milk
pg. 20
Poster 7: Characterization of starch hydrolysis inhibitors in Lepisanthes alata pg. 21
Poster 8: Stability of health-promoting compounds in Colombian Cape gooseberry (Physalis peruviana L.) and its products from a supply chain perspective
pg. 22
Poster 9: Effects of salt and sugar addition on the properties of fish gelatin by nanostructural and physicochemical analyses
pg. 23
Poster 10: Extraction and characterization of proteins from five insect species pg. 24
Poster 11: Antibacterial effect of LEDs on Salmonella spp. in orange juice – Influence of temperature and irradiance
pg. 26
Poster 12: Novel processing technologies and novel protein foods pg. 27
Poster 13: Effects of high-intensity 405 nm light emitting diode on inactivation of Gram-negative foodborne pathogens
pg. 28
Poster 14: Production and valorisation of high quality proteins from insects pg. 30
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
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Poster 15: Temperature adaptation alters Salmonella Enteritidis heat/acid resistance, membrane lipid composition and stress/virulence related gene expression
pg. 31
Poster 16: Interplay of consumer psychology, product properties and sensory perception on the consumer acceptance of insects as food
pg. 32
Poster 17: Optimization of real-time PCR method combined with immunomagnetic separation for detecting healthy and heat-injured Salmonella Typhimurium on raw duck wings
pg. 34
Poster 18: Dynamic texture perception and food oral breakdown pg. 35
Poster 19: Masticatory effort and bolus formation during oral processing of bread in relation to its physicochemical properties
pg. 37
Poster 20: Oral coatings, tastant migration and perception pg. 38
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
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Programme
09:30 – 10:10 Opening address and overview of NUS FST/Food Quality and Design Group
Dr HUANG Dejian Associate Professor, Acting Programme Director, Food Science and Technology Programme, NUS
Dr Vincenzo FOGLIANO Professor, Chair, Food Quality and Design Group, WUR
10:10 – 10:30 Coffee break, get-to-know-each other session Presentation session 1
10:30 – 10:50 Volatile organic compounds synthetized by specific spoilage organisms as spoilage indicators of raw salmon fillets
Dr Marta MIKŠ-KRAJNIK Visiting research fellow, NUS
10:50 – 11:10 Detection of chemical adulterations in spices
Miss Isabelle SILVIS Postgraduate student, WUR
11:10 – 11:30 Chemical and volatile composition of lychee wines fermented with three non-Saccharomyces yeast strains
Miss CHEN Dai Postgraduate student, NUS
11:30 – 11:50 Processing of several tropical fruits: Understanding the effect on the sensory properties, texture and nutritional composition
Miss Ita SULISTYAWATI Postgraduate student, WUR
11:50 – 13:30 Lunch break and poster viewing
13:30 – 14:00 Laboratory visit
Presentation session 2
14:00 – 14:20 Influence of fatty acid composition and stereochemistry of triacylglycerols on physical properties of milk fat
Miss Daylan A. TZOMPA SOSA Post-doctoral fellow, WUR
14:20 – 14:40 Frozen bread dough: Mathematical modelling and controller design
Mr Turkay KONDACKI Postgraduate student, NUS
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
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14:40 – 15:00 Bioactive properties of red sorghum bio-colorant and their derivatives
Mr Folachodé AKOGOU Postgraduate student, WUR
15:00 – 15:20 Organopolysulfides with potential H2S-releasing activity from shallot (Allium cepa L. Aggregatum Group) and stinky beans (Parkia speciosa)
Mr Restituto T. TOCMO Postgraduate student, NUS
15:20 – 16:00 Tea break and poster viewing
Presentation session 3
16:00 – 17:30 Food and nutrition: Perspectives from the government, industry, and academia
Ms Sharon SIA Senior Executive, Health Promotion Board
Dr Marjolijn BRAGT Manager, FrieslandCampina Institute International
Dr Jeya HENRY Professor, Director, Clinical Nutrition Research Centre, Singapore Institute of Clinical Sciences, A*STAR
17:30 – 18:00 Closing ceremony and remarks
Dr HUANG Dejian Associate Professor, Acting Programme Director, Food Science and Technology Programme, NUS
Dr Vincenzo FOGLIANO Professor, Chair, Food Quality and Design Group, WUR
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
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Volatile organic compounds synthetized by specific spoilage organisms as spoilage indicators of raw salmon fillets
Marta MIKŠ-KRAJNIK1,2, YOON Yong-Jin3, and YUK Hyun-Gyun1,4,*
1 Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
2 Chair of Industrial and Food Microbiology, Faculty of Food Science, University of Warmia and Mazury in Olsztyn, Plac Cieszyński 1, 10-726 Olsztyn, Poland
3 Division of Engineering Mechanics, School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
4 National University of Singapore (Suzhou) Research Institute, No. 377 Linquan Street, Suzhou Industrial Park, Suzhou, Jiangsu, China 215123
* Corresponding author: [email protected]
Abstract
Specific spoilage organisms (SSOs) are the major cause of spoilage of perishable food, like raw
salmon. As the effect of their metabolic activity, volatile organic compounds (VOCs) are synthetized,
causing off-odours. This study aimed to identify unique VOCs as possible spoilage indicators of raw
salmon spoilage stored aerobically under different temperature conditions and to characterize SSOs
growth dynamics. The growth of total viable count (TVC) and seven SSOs namely: psychrotrophs,
Pseudomonas spp., coliforms, lactic acid bacteria (LAB), Brochothrix thermosphacta, H2S producing
bacteria and yeasts and moulds were investigated at 4, 10 and 21 °C. The VOCs were determined by
HS-SPME-GC-MS. The maximum growth rates (µmax), shelf lives, spoilage (S) and maximum (M)
values for TVC and SSOs were calculated with the modified Gompertz model. In spoiled salmon, the
major SSOs characterized by the highest µmax, S and M values were psychrotrophs, probably
represented by Pseudomonas spp. The estimated microbial shelf lives (TVC) of salmon were 3.02,
1.82 and 0.60 days at 4, 10 and 21 °C, respectively. Significant correlations were observed between
TVC/SSOs and VOCs for trimethylamine, ethanol, 3-methyl-1-butanol, acetoin, acetic acid and 2,3-
butanediol in all conditions. The selected VOCs might be used as promising spoilage indicators for
raw salmon.
About the speaker
Dr Marta Mikš-Krajnik obtained her PhD degree in 2011 from Faculty of Food
Science, University of Warmia and Mazury in Olsztyn (Poland), where subsequently
she worked as Assistant Professor. Currently, she is a Visiting Research Fellow
under the supervision of Assistant Professor Yuk Hyun-Gyun in FST programme
(NUS). Her previous research focused on physiological state and metabolism of
lactic and propionic acid bacteria as well as the detection of starter cultures with 16/23S rRNA
oligonucleotide probes.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 6
Detection of chemical adulterations in spices
Isabelle SILVIS1,2, and Saskia VAN RUTH*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
2 RIKILT, 6708 WB WAGENINGEN, the Netherlands
* Corresponding author: [email protected]
Abstract
Foods scandals, recently reported in the media as the addition of melamine in infant formula and the
substitution of beef with horsemeat, made consumers more aware of the vulnerability of food in the
links of the processing chain. Especially condiments as spices are susceptible to fraud as there origin
is often hard to trace. Examples of currently used methods in the detection of adulterations are
targeted DNA based techniques as PCR. With this method it is possible to find, what you are looking
for. If you are looking for the DNA of horsemeat, this technique will tell you whether it is absent or
present, but not in which quantity. PCR is time consuming and highly trained personnel are required.
Therefore, due to these drawbacks the advantages of untargeted methods are investigated and their
suitability in producing a comprehensive overview of the chemical content of a food matrix. Major
challenge is to determine if a combination of the detection of volatiles and non-volatiles combined
with multivariate data analysis works in obtaining a chemical fingerprint of the food matrix. The
chemical composition of adulterated material shall be distinctive after multivariate data analysis from
the authentic samples. Challenge is to determine how these untargeted methods can be implemented
in industry to reduce the tension for people in the food chain to commit food fraud. The methods that
we use now are the Proton Transfer Mass Spectrometry and the Direct Infusion Mass Spectrometry.
About the speaker
Miss Isabelle Silvis began her bachelor in Food Technology in Wageningen in
2007. As she was interested in different cultures and countries, she continued with
the European Master in Food studies that allowed her to study food related courses
in three other European countries and to taste their authentic flavours. Currently,
she is in the second year of her PhD, working on the authenticity of herbs and
spices.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
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Chemical and volatile composition of lychee wines fermented with three non-Saccharomyces yeast strains
CHEN Dai1, YAP Zhi Yin1, and LIU Shao-Quan1,2,*
1 Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 3, Singapore 117543
2 National University of Singapore (Suzhou) Research Institute, No. 377 Linquan Street, Suzhou Industrial Park, Suzhou, Jiangsu, China 215123
* Corresponding author: [email protected]
Abstract
This study was conducted to examine the effects of three non-Saccharomyces yeasts (Williopsis
saturnus var.saturnus NCYC 22, Torulaspora delbrueckii PRELUDE and Kluyveromyces lactis KL
71) on non-volatile and volatile composition of lychee wine. Growth of the non-Saccharomyces
yeasts was significantly different in the lychee fermentations. Additionally, the utilization of sugars
and the production of volatile compounds such as ethanol, esters and the retention of some juice
volatiles such as terpene compounds differed significantly among the fermentations by different yeast
strains. T. delbrueckii PRELUDE was shown to have the best ability to grow, utilize sugars and
produce ethanol (around 8 %), as well as to generate fruity ethyl esters (ethyl octanoate and decanoate)
and to retain main terpene compounds (cis-rose oxide and linalool). The lychee wine fermented with
T. delbrueckii PRELUDE was the most preferred among the treatments, which could be selected as a
desirable non-Saccharomyces yeast strain for lychee wine fermentation.
About the speaker
Miss Chen Dai is currently a PhD candidate at the Food Science and Technology
Programme at the National University of Singapore, under the supervision of
Associate Professor Liu Shao-Quan. She obtained her Bachelor of Engineering in
Viticulture and Enology Engineering, and Master of Engineering in Food
Biotechnology degrees from the College of Food Science & Nutritional Engineering
at China Agricultural University. Her current research is focusing on the chemical and volatile
composition of lychee wines produced by fermentation.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 8
Processing of several tropical fruits: Understanding the effect on the sensory properties, texture and nutritional composition
Ita SULISTYAWATI1,2, Matthijs DEKKER, Ruud VERKERK, and Vincenzo FOGLIANO* 1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, The
Netherlands 2 Indonesia Directorate General of Higher Education (DGHE/DIKTI)
* Corresponding author: [email protected]
Abstract
The world production of tropical fruit variety from the most to less dominant are mango, pineapple,
papaya and avocado, respectively. Among the minor tropical fruits of global production, guava poses
the largest contribution, followed by lychees, longan, durian, rambutan and passion fruit. From
various processed fruit products existing, dried/dehydrated fruits are attaining substantial attention,
and recently the availability of those fruits products in the market has increased considerably. Dried
fruit is higher in energy per serving than fresh, canned, frozen fruit and most fruit juices, so it makes
them a good source of dietary fibre and most of them contain vitamins (especially vitamin A) and
phytochemicals. Meanwhile, it is well known that drying, and indeed other thermal and even non-
thermal processing, leads to a number of changes of the fruit material, include physical, chemical
and/or biochemical changes.
Aims
- investigate the effects of processing (especially osmotic dehydration and drying techniques)
of several tropical fruits (i.e. pineapple, mango, papaya, guava) on the microstructural
changes, β-carotene and antioxidant activity
- study the effect of matrix modification (i.e. calcium salts addition) on the osmotic dehydrated
and dried fruits in terms of the microstructural changes, β-carotene, antioxidant activity and
sensory perception
- understand the role of residual enzymes in the quality of dried fruits during storage
- study the key quality features of dried fruits valued by consumers
About the speaker
Miss Ita Sulistyawati graduated with a MSc in Urban Environmental
Management, from Wageningen University, The Netherlands. She is a lecturer at
Food Technology Department of Soegijapranata Catholic University in Indonesia.
Currently she is a first year PhD fellow at Food Quality and Design group of
Wageningen University, The Netherlands. Her interest include food quality, food
sensory and food safety.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 9
Influence of fatty acid composition and stereochemistry of triacylglycerols on physical properties of milk fat
Daylan A. TZOMPA SOSA1,2, George VAN AKEN, Hein VAN VALENBERG, Henk BOVENHUIS, Toon VAN HOOIJDONK*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
2 CONACYT (Consejo Nacional de Ciencia y Tecnología)
* Corresponding author: [email protected]
Abstract
Selective breeding and feeding make a significant contribution to changes in the fatty acid and
triacylglycerol profile of bovine’s milk fat that in turn affect the thermal behaviour (polymorphic
transitions and melting behaviour) of milk fat. Modification in the fatty acid and triacylglycerol
profile will probably lead to a rearrangement of the TAG molecule, which will also influence the
physical properties of milk fat. A deep understanding of the thermal behaviour of milk fat is of
importance for rich fat products, and for industrial purposes such as for milk fat fractionation. Milk fat
with different physical profiles and various stereochemistry structures are desirable for the dairy
industry in order to develop functional products. These different profiles could be obtained in a
natural way by selective breeding and feeding.
Milk fat with different genetic profiles were submitted to thermal behaviour analysis (DSC) and to
fatty acid (GC-FID) and triacylglycerol profiling (GC-FID and HPLC-ELSD). The structure analysis
of milk fat triacylglycerols was determined with a regiospecific approach. This research will try to
establish the influence of genetics, fatty acid and triglyceride profile on the physical properties of
bovine milk fat. With this knowledge, bovine MF could be modified for different needs.
Aims
Understand the relation between fatty acid and triacylglycerol profile on the thermal behaviour of milk fat.
Study milk fat triacylglycerol structure and its relation with fatty acid profile and DGAT1 genotype.
Increase the knowledge on milk fat thermal behaviour.
About the speaker
Miss Daylan Tzompa is currently a post-doc at the Dairy Science Group of
Wageningen University. She works on physical and chemical properties of lipids
from various sources. Her main work is on the effect of DGAT1 on the physical and
chemical properties of bovine milk fat triacylglycerols. She also has worked on the
effect of lipid extraction on insect lipids. Daylan is Mexican and likes dancing,
climbing and swimming.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 10
Frozen bread dough: Mathematical modelling and controller design
Turkay KONDACKI and ZHOU Weibiao *
Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
* Corresponding author: [email protected]
Abstract
It is essential to understand and quantify the mechanisms of heat transfer between the food and the
heat transfer medium during freezing. Freezing process for bread dough shows non-linear dynamics
during phase change stage. Hence, mathematical modelling of freezing may improve the
understanding of the freezing process and help to overcome the issues of dough quality during
freezing.
This research was aimed to develop mathematical models of freezing process for bread dough. A
two dimensional hemispherical model has been used to represent the shape of bread dough. The heat
transfer model produced a good agreement with the experimental data, resulting in a high coefficient
of determination (R2) and a low root mean square error (RMSE). It has been confirmed that the model
has a good performance and can be used to predict temperature profiles in the dough during freezing
process. Therefore, a controller design becomes valuable to enhance the quality of frozen dough.
A closed loop control system has been designed in Labview for a blast freezer. Effects of the
freezing process on baked bread quality have been investigated employing a PI-Controller design
which is mostly known as a classical control technique in food industry. It has been concluded that
PI-controlled freezing process showed improved quality characteristics compared to conventional
freezing methods.
About the speaker
Mr Turkay Kondakci is a PhD student working with Professor Zhou Weibiao. He
received his Bachelor’s degree from Department of Food Engineering in Istanbul
Technical University, Turkey. He then pursued his postgraduate studies in the NUS-
FST programme after he was awarded the A*STAR-SINGA scholarship. His
research work focuses on functional foods, modelling, baking process, freezing
process and advanced process control.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 11
Bioactive properties of red sorghum bio-colorant and their derivatives
Folachodé AKOGOU1,2,3,Polycarpe KAYODÉ,Heidy DEN BESTEN,Anita
LINNEMANN,and Vincenzo FOGLIANO* 1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, The
Netherlands 2 Laboratory of Valorization and Quality Management of Food Bio-Ingredients (LaBio), DNSA/FSA
Université d’Abomey-Calavi, Benin 3 Laboratory of Food Microbiology (WUR),Wageningen University & Research Centre, 6700 AA Wageningen,
The Netherlands * Corresponding author: [email protected]
Abstract
Dye sorghum leaf sheaths are is a good source of 3-deoxyanthocyanins. In addition, the stability of
dimeric 3-deoxyanthocyanins in acid and neutral conditions increased the interest of 3-
doexyanthocyanin for food industry. In West Africa, sorghum colorant has been used in food and in
blood related ailments. In Benin, the water extract of the pigment is intensively applied in foods as
colorant and as preservative agent. Our objectives are to provide qualitative and quantitative data on
the extraction methods of the colorant, its applications on foods, the consumption of dyed foods in
Benin and the consumer’s perception on dyed foods. Cool alkaline extraction is the most efficient
method traditionally used to extract anthocyanins. Nevertheless, 82.6% of anthocyanin is non-
extracted using traditional methods. Sorghum colorants are applied in fermented (koko) and non-
fermented foods (wagashi). Koko is a fermented maize-based infant porridge dyed to treat related
blood ailment. Wagashi, soft West African is dye for aesthetic reason and for preservative purpose.
The application of sorghum colorants in infant fermented food like koko and on wagashi raise the
interest for the accessibility of minerals in infant foods like koko, the effect sorghum colorant might
have on the growth of lactic bacteria and its role on the wagashi preservation The perspectives are
then structured on two main points: the effect of sorghum colorant on microorganism growth and the
mineral accessibility in dyed foods.
.
About the speaker
Mr Folachodé Akogou started his university studies at the University of Abomey-
Calavi in Benin where he got an Engineer degree in Nutrition and Food Science at the
Faculty of Agronomic Sciences in 2009. He is currently doing a PhD study on the
bioactive properties of sorghum biocolorant at Wagenigen University, The
Netherlands.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 12
Organopolysulfides with potential H2S-releasing activity from shallot (Allium cepa L. Aggregatum Group) and stinky beans (Parkia speciosa)
Restituto TOCMO, LIANG Dong, WANG Chenhui, and HUANG Dejian*
Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
* Corresponding author: [email protected]
Abstract
Organosulfur-rich foods have been highly regarded for their broad spectrum of benefits in
disease prevention, particularly in promoting cardiovascular health. The discovery of
hydrogen sulfide (H2S) as an important endogenous signaling molecule has provided a new
avenue of research on organosulfur-rich foods as potential dietary sources of H2S donors. The
purported health benefits of dietary organosulfides via their H2S releasing activity, however,
remains an underexplored area of research and poses a considerable amount of challenge.
One of the complexities is brought about by the labile nature of organosulfur compounds,
which readily undergo chemical transformations under various processing conditions. In this
study, we characterized the organopolysulfide compositions of two tropical vegetables,
shallot and stinky beans, and investigated the effects of extraction methods, pH, and different
processing conditions on their organopolysulfide profiles. Lipophilic extracts and essential
oils were obtained by solvent extraction (SE) and hydrodistillation (DI), respectively, and
analyzed by GC and GC-MS/FID. Various sulfur-containing compounds, including disulfides,
trisulfides, and cyclic organosulfides were identified in shallot, whereas, nine cyclic
organopolysulfides with three to five tethering sulfur atoms in their chemical structures were
detected in stinky beans. We found significant differences in the quantitative and qualitative
profiles of organosulfur compounds as affected by the oil isolation methods (SE vs DI), pHs,
and processing conditions. The application of heat (cooking), autoclaving, and freeze-drying
significantly altered the concentrations of organic polysulfides as compared to those of
untreated samples. These results provide information on the effects of several factors that are
relevant for optimizing extraction and isolation of organopolysulfides from dietary sources.
We tested the H2S releasing activity of stinky bean oil in Mcf-7 cells using an H2S
fluorescent probe and preliminary results indicate that stinky bean oil has high H2S releasing
activity. Since processing conditions can greatly alter the polysulfide profiles in foods, an
H2S releasing activity guided optimization of processing conditions would lead to optimal
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 13
effectiveness of supplements or functional foods based on Alliums and stinky beans for their
cardiovascular health promoting functions.
Fig. 1. Dietary organopolysulfides as potential H2S donors.
About the speaker
Mr Resty Tocmo obtained an MSc in Food Science from Cornell University (2012).
Currently, he is a PhD student in the lab of Assoc. Professor Dejian Huang of the
NUS FST Programme. His research work focuses on the characterization, isolation,
and purification of organopolysulfides from organosulfide-rich dietary sources for
their H2S releasing activity.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 14
Application of novel ingredients and technologies to nutritional powders - Effects on its physicochemical properties
THAM Wei Yi Tammie and Zhou Weibiao*
Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
* Corresponding author: [email protected]
Abstract
Nutritional powders are specially designed products that contain essential ingredients to fulfil
nutritional requirements or act as supplements. Due to its complexity, conventional processing affects
its physicochemical properties and functionality. This paper aims to review the use of various novel
ingredients and emerging technologies in nutritional powders and their effects on its physicochemical
properties.
Several novel ingredients that are safe, nutritive and aid physicochemical stability are trehalose, n-
ocetenylsuccinate-derivatized starch (n-OSA) and inulin. For example, trehalose has unique
physicochemical properties such as high glass transition temperature (Tg), ability to retain glassy state
at high temperature, low hygroscopic profile and stability in the presence of other components.
Microcapsules with trehalose stored under low relative humidity had decreased lipid oxidation due to
its binding affinity to dienes while retaining its glassy state. Low viscosity n-OSA starch is
amphiphilic and it stabilized microencapsulated hydrophobic components and reduced the
coalescence of oil droplets under moderate spray-drying conditions. Besides improving gut microflora,
inulin that have high molecular weight could aid both processing and storage stability.
The application of novel processing technologies such as microencapsulation, extrusion
porosification and protein conjugation can be used independently or in combination with these novel
ingredients to enhance stability during processing and improve its functional properties.
Microencapsulation using ingredients such as trehalose and n-OSA starch, prevented oxidative
deterioration and enabled developments in controlled-release mechanisms. Extrusion porosification of
milk protein concentrate had high dispersibility index which enhanced its rehydration behaviour due
to casein micelle dissociation prior to drying. Protein conjugation of various milk proteins and
polysaccharidesimproved heat stability and protein solubility at the isoelectric pH during processing.
Further research is required to understand the physicochemical properties, overall stability,
component interactions, safety and nutrition of the finished product after introducing both novel
ingredients and processing technologies. In addition, industrial application must be practical and
economical in order to implement these improvements in nutritional powders.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 15
About the author
Miss Tammie Tham graduated with a B. Sc in Food Science and Technology from
the University of New South Wales (UNSW), Australia. She is an FST PhD student
under the EDB IPP Scholarship. Her PhD work focuses on the physicochemical
characteristics of infant nutritional formula.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 16
Effect of intensely heated milk proteins on the development of immune tolerance to milk allergens
LIU Fahui1,2, Kasper HETTINGA, Harry WICHERS, and Tiny VAN BOEKEL*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
2 Food Bio-Based research, 6708 WB WAGENINGEN, The Netherlands
* Corresponding author: [email protected]
Abstract
Food allergy is an adverse health effect arising from a specific immune response. Cow’s milk is one
of the leading causes of food allergy especially in infants. Previous studies have estimated the
prevalence of hypersensitivity to cow’s milk from 0.6% to 2.5%. However, most studies have shown
the prognosis of developing immune tolerance to cow’s milk to be good, with the majority
outgrowing their allergy by the age of 3 years. It was reported that intensely heated (baked) milk
products contribute to the development of immune tolerance to cow’s milk allergens.
This work focuses on the mechanism of this observation and the possible compounds that may
contribute to the induction of immune tolerance. The chemical and physical properties of the heated
proteins, such as the secondary structures, available amino acids, particle size, antigenicity and the
like, were studied in this work. The amount of furosine was also measured by HPLC to reflect the
level of Maillard reaction. Then all the heated and unheated proteins were digested and absorbed in
vitro. All samples are resistant to gastric digestion, but not to the duodenal digestion. After that, the
antigenicity of the digesta was measured.
We find that the destruction of protein conformational structures resulted in the decrease of the
antigenicity of milk whey proteins. In addition, aggregates were formed during heat treatment, the
particle size of the aggregates was related to the change of antigenicity. These aggregates result from
aggregation of proteins or Maillard reaction may be the important compounds responsible for the
induction of immune tolerance.
About the author
Mr Liu Fahui comes from China and is working as a PhD student at the Dairy
Science Group of Wageningen University. The research topic is the introduction of
immune tolerance to cow’s milk allergens. He got the Master degree from
Nanchang University, China. Fahui likes computer graphics, guitar and basketball.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 17
Authentication of edible bird’s nest using GC/MS
CHUA Yong Guan Peter1, LEONG Lai Peng2, Bosco Chen BLOODWORTH3, and Sam LI Fong Yau1,*
1 Department of Chemistry, National University of Singapore 2 Food Science and Technology Programme, Department of Chemistry, National University of Singapore,
Science Drive 3, Singapore 117543 3 Food Laboratory, Centre of Analytical Sciences, Health Sciences Authority
* Corresponding author: [email protected]
Abstract
An approach was developed and validated for the authentication of edible bird’s nest (EBN) using
gas chromatography coupled with mass spectrometer (GC/MS) and multivariate analysis. The
approach comprises of qualitative and quantitative discrimination of EBN and spiked samples. The
detectable spiking level for qualitative discrimination was as low as 0.5 % of the sample. Meanwhile,
in quantitative discrimination the approach was able to achieve an accurate detectable as low as 1 %.
The success of qualitative and quantitative discrimination of EBN and a low level of spiked samples
illustrate the feasibility of employing one analytical method for the authentication of EBN.
About the presenter
Mr Chua Yong Guan is currently a research assistant at the National University of Singapore. His
research interests include food characterisation, and toxins in food and water. His research work on
edible bird’s nest has been published in several international conferences and also in international
journals.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 18
Shortening the dry period of the dairy cow – influence on milk composition and quality
Reuben DE VRIES1,2, Kasper HETTINGA, and Toon VAN HOOIJDONK*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, The Netherlands
2 Swedish University for Agricultural Sciences (SLU) Uppsala, Sweden
* Corresponding author: [email protected]
Abstract
Dairy cows are commonly subjected to a dry period–a period without milking the cow- of
approximately 8 weeks between two lactations. This has been done since the beginning of the 20th
century, because of the high milk production at beginning of the next lactation. This high production
results in a negative energy balance (NEB) at the beginning of lactation, since the sudden increase in
production is not compensated by feed intake. This NEB is related to a decreased health status, and
can result in metabolic, immunity and fertility problems. When a shorter or no dry period is applied, a
lower peak production and a better energy balance of the cow are obtained.
Milk samples of three different cow breeds are analysed in this study. Cows are subjected to a
normal, a shortened or no dry period. Samples are taken both before and after calving at several time
points. Protein profiles, mainly caseins, are analysed with capillary zone electrophoresis and high
performance liquid chromatography. These techniques allow quantification all caseins, including
levels of phosphorlylation and glycosylation, and thus indicate processability of milk. Proteomic
analyses are done with LC-MS/MS technology, which is able to identify >250 proteins in milk,
including important immune proteins for the offspring. Increased knowledge of milk composition
when shortening the dry period is needed with regard to processability of milk as well as cow and calf
health. This study has the aim to study milk composition and quality of cows with a shortened or no
dry period, with focus on:
- The profile of highly abundant proteins in milk - The proteome of colostrum and milk - Processing quality of the milk
About the author
Mr Reuben de Vries’s education traject was completed in his home country the
Netherlands, finishing as an MSc in Food Technology at Wageningen UR in 2012
with specialisation Dairy Science and Technology. After graduation he started his
PhD, entitled 'Shortening the dry period of the dairy cow - influence on milk
composition and quality'. This is a joint project of Wageningen UR and the Swedish
University of Agricultural Sciences (SLU) in Uppsala. Besides working he spend his time with
cycling, running and playing badminton.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 19
The impact of structural modifications of dracoflavan B on their alpha-amylase inhibition activity
TOH Zhi Siang, LU Yuyun, and HUANG Dejian*
Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 3, Singapore 117543
* Corresponding author: [email protected]
Abstract
Type II diabetes is an escalating problem worldwide where the number of cases can rise up to 552
million by the year 2030. Effective hyperglycaemia control can be achieved via the retardation of
starch digestive enzymes like α-amylase which have been targeted by many anti-diabetic drugs. In
this research, the A and B type dracoflavan B inhibition against pancreatic α-amylase were
investigated. Additionally, a series of chemical modifications such as esterification, sulphation and
demethylation were performed on dracoflavan B to probe its structural activity relationship (SAR)
towards α-amylase inhibition. Both the A and B type dracoflavan B strongly suppressed the
hydrolysis of starch by α-amylase with IC50 values of 23.2 and 27.6 µM respectively. Comparatively,
the A type dracoflavan B is only 16% more potent than their B type diastereomer. This result
highlighted that there is no stereospecific requirement for dracoflavan B to inhibit α-amylase.
Conversely, SAR studies demonstrated that the hydroxyl and methoxy groups of dracoflavan B are
essential for its α-amylase retardation. The turbidity assay results on starch digestion revealed that
esterification, sulphation and demethylation on these functional groups led to loss of α-amylase
inhibition. The SAR finding provides an important direction for future dracoflavan B modifications to
enhance its α-amylase inhibition.
About the presenter
Mr Toh Zhi Siang is currently a PhD student at the Food Science and Technology
Programme at the National University of Singapore. He graduated from Nanyang
Technological University with a B. Sc. in chemistry and biological chemistry. He is
currently working on inhibition of starch hydrolysis using derivatives of dracoflavan
B, under the supervision of Associate Professor Huang Dejian.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 20
Proteomic study of the dynamics in immune proteins between human milk and bovine milk
Lina ZHANG1,2 , Kasper HETTINGA, and Toon VAN HOOIJDONK*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, The Netherlands
2 Bio-chemistry Group, Wageningen University & Research Centre, 6700 ET Wageningen
* Corresponding author: [email protected]
Abstract
Milk is the most important food for the growth and development of the neonate because of its
unique nutrient composition combined with the presence of many bioactive proteins. One of the most
interesting components, the immune proteins, plays a pivotal role in protecting the gut mucosa against
pathogens and achieving many beneficial outcomes for the immunity status of the neonate. The two
main functions of immune proteins are protecting the mammary gland against mastitis and providing
the neonate with an immunological defence against pathogen. Milk composition is not constant due to
many factors, such as, health status, lactation stage, individual differences and species differences.
Some, mainly qualprtive, studies have already been done to describe the high abundant immune
proteins in both human and bovine milk, but the knowledge on dynamics of the low abundant immune
proteins is still very limited.
The objective of this project is to study the extent and causes of variation in immune proteins from
both human and bovine milk using an advanced proteomics techniques, filter aided sample
preparation and dimethyl labelling combined with LC-MS/MS. The researches will be carried out in
four parts as shown follows: 1. The influence of healthy status on the bovine milk proteome,
especially on immune proteome; 2. The milk proteome of human and bovine milk over lactation; 3.
The differences in the milk proteome between individual mothers and between individual cows; 4.
The differences between human and bovine milk proteome. Detailed determination of the dynamics in
immune proteins in human and bovine milk not only help in understanding the role of immune
proteins for cow and human healthy but also contribute to our knowledge on the differences in the
needs of calves and babies. The comprehensive understanding in the dynamic of bovine and human
milk proteome may therefore provide guidance on how to develop infant formulas more similar in
protein composition to human milk.
About the author
Miss Lina Zhang comes from China. She studied on Food Science and Technology
during her Bachelor and agricultural products processing and preservation
engineering during der Master in China Agricultural University. Now, she is doing
PhD in Wageningen University. Her research topic is about the dynamic of immune
proteins in both human milk and bovine milk.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 21
Characterization of starch hydrolysis inhibitors in Lepisanthes alata
ZHANG Yan, Adeline WONG Ik Chian, and HUANG Dejian*
Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
* Corresponding author: [email protected]
Abstract
Type-II diabetes is a chronic disease with gradual deterioration in glucose metabolism. Postprandial
hyperglycemia is a concern in the management of type-II diabetes. Inhibition of α-amylase is
postulated to be a preventive treatment among the available antidiabetic therapeutic methods. After
screening around 350 natural plants from Singapore Botanical Gardens as starch hydrolase inhibitors,
we discovered a promising edible plant named Lepisanthes alata (Sapindaceae Family) with
extremely high α-amylase inhibition. The leaves of Lepisanthes alata show higher α-amylase
inhibitory activity (IC50 = 0.007±0.001 mg/ml; equals to 1643.939 μmol acarbose equivalent/g) than
that of the barks (IC50 = 0.012±0.001 mg/ml; equals to 863.934 μmol acarbose equivalent/g). Defat
leaves with hexane before extraction of leaves with a mixture of acetone, ethanol, H2O, and acetic
acid (40.0:40.0:19.9:0.1, v/v). Evaporation of the supernatant centrifuged from mixture resulted in
solid extracts. Fractionation of crude extracts was carried out by a solid-liquid extraction method,
which is to wash crude extracts by ethyl acetate, chloroform, n-Butanol, and H2O in sequence.
Chloroform fraction and aqueous fraction show relatively high α-amylase inhibitory activity, which
have IC50 values of 0.025±0.002 mg/ml and 0.0024 mg/ml, respectively. The structural information
of the active compounds are further elucidated by LCMSn approach.
About the presenter
Miss Zhang Yan completed her Bachelor’s degree and Master’s degree in
Northeast Agricultural University and her majors are Food Science and Engineering,
and Cereals, Oil and Vegetable Protein Engineering, respectively. Currently, she is a
PhD student under Associate Professor Huang Dejian in FST, and she focuses on
isolation and characterization of bioactive compounds from leaves of Lepisanthes
alata and analysis of its starch hydrolase inhibitory activity.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 22
Stability of health-promoting compounds in Colombian Cape gooseberry (Physalis peruviana L.) and its products from a supply chain perspective
Mary Luz OLIVARES TENORIO1,2, and Anita LINNEMANN*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, The Netherlands
2 Uniagraria (Fundación Universitaria Agraria de Colombia)
* Corresponding author: [email protected]
Abstract
Cape gooseberries are fruits of the plant Physalis peruviana L. that belongs to the Solanaceae family
and contains health-promoting compounds. The small yellow to orange fruits have cherry tomato-like
appearance and sour-sweet flavour. They also have a juicy pulp that contains many kernels. Currently,
Cape gooseberry gains popularity at European markets due to its attractive appearance and is
appreciated for decoration in high cuisine. Main current producer is Colombia, followed by South
Africa. Research indicates that the gooseberry could become a fruit of particular interest to the food
industry given its contents of b-carotene, vitamin C, flavonoids and for its antioxidant activity. This
study aims to determine the thermal stability of these compounds.
About the presenter
Ms Mary Luz is from Colombia. She obtained her bachelor in food engineering
at the Fundación Universitaria Agraria de Colombia in 1998. She has worked in
food industry, especially in the sector of food services in the area of food quality
and food safety. In 2006, she received her Msc in Food Quality Management at
Wageningen University in The Netherlands, which she followed thanks to a
fellowship granted by NUFFIC. Since 2007, she has been working at Fundación Universitaria de
Colombia, her alma máter, as lecturer and now she is the director of the program of food engineering,
already for 5 years. In 2012, she was granted by NUFFIC again with a fellowship to pursuit PhD
program in the group of food quality and design at Wageningen University. Her graduation date is
expected in 2016. She is very social persona, likes to go out, read, listen to music and go to movies.
She has a lovely son whose name is Tomas.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 23
Effects of salt and sugar addition on the properties of fish gelatin by nanostructural and physicochemical analyses
SOW Li Cheng and YANG Hongshun*
1 Food Science and Technology Programme, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
* Corresponding author: [email protected]
Abstract
Application of fish gelatin as a food component in replace of mammalian sources has attracted
attentions recently. However, physicochemical properties of fish gelatin might be affected by other
food components thus affecting its application. To determine whether and how sugar and salt
components in food affect the physicochemical properties of fish gelatin, nanostructure of tilapia fish
gelatin was studied by atomic force microscopy (AFM) with the secondary structure investigated by
Fourier transform infrared (FTIR) spectroscopy. The results indicated that 1.5% NaCl addition led to
a loss in molecular order in secondary structure which was accompanied with reducted gel strength;
however, addition of 1.5 % sucrose did not affect physicochemical and structural properties of fish
gelatin. Fish gelatin possessed heterogeneous nanostructure including spherical aggregates, ring like
structure, short and long rods as well as continuous fibre network. Incorporation of NaCl with fish
gelatin increased diameter of spherical aggregates to more than two folds of control. These data
suggest that addition of sodium chloride reduced gel strength through inducing large nano-aggregates,
which could be at improper alignment that prevented the formation of a rigid gel. Interestingly, the
fish skin gelatin studied here showed good storage stability over 30 days of storage at 4°C. Sodium
chloride affects fish gelatin’s nanostructure and physicochemical properties more than sucrose at the
same concentration.
About the presenter
Miss Sow Li Cheng graduated with a BSc with Honours from the National University
of Singapore, Food Science and Technology programme. She is currently a first year
PhD student doing her PhD under Assistant Professor Yang Hongshun. One special
area of interest of her work under Assistant Professor Yang Hongshun is to apply
atomic force microscopy to study the nanostructure of food. Her previous work
during her honours project was to study the impact of salt and sugar on the nanostructure of fish
gelatin. Her current on-going work is to develop a nanoemulsion based food coating for seafood
products to extend their shelf life.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 24
Extraction and characterization of proteins from five insect species
YI Liya, Catriona LAKEMOND, and Tiny VAN BOEKEL*
Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
* Corresponding author: [email protected]
Abstract
Insects are now seriously considered as an alternative and additional source of protein in developed
countries in view of an increasing world population and the environmental problems caused by
conventional cattle.
In many countries of South America and Africa, edible insects are habitually used as animal protein
food for human consumption. However, people in the western world on average have a strong bias
against insects as food, which will hamper them to eat insects, especially when the insects are offered
in a recognizable form (including egg, larvae, pupae or adult). However, it is also possible to extract
proteins from insects for further use in food products. In view of consumer acceptance, this is
particularly relevant for countries with no habit of consuming insects, such as Europe and North
America.
Very little information from a food science point of view is available on characteristics and
functionality of extracted insect proteins. The aim of this study is to extract proteins from insects,
namely the Yellow mealworm (Tenebrio molitor), the Super mealworm (Zophobas morio), the Lesser
mealworm (Alphitobius diaperinus), crickets (Acheta domesticus) and cockroach (Blaptica dubia), in
order to characterize the obtained protein fractions and to establish their functional properties.
During the extraction procedure, firstly, fresh insects were frozen by liquid nitrogen. After adding
demineralized water and blending, the insect suspension obtained was sieved and a suspension and a
residue were collected. After centrifugation, three fractions were obtained from the filtrate:
supernatant, pellet, and fat. The supernatant and pellet fractions are characterized in terms of protein
content (Dumas analysis), molecular weight (SDS-PAGE), and functionality (foam & gel formation).
Furthermore, amino acid compositions of five insect species are also determined by using reversed
phase C18 HPLC.
It was found that crude protein content of five insect species studied ranged from 19 - 22 %.
Essential amino acid levels in all insect species were comparable with soybean proteins, but lower
than for casein. After aqueous extraction, next to a fat fraction, supernatant, pellet, and residue
fractions contained 17 – 23 %, 33 – 39 %, 31 – 47 % of total protein, respectively. The storage
modulus G' is a measure for the elastic energy stored reversibly in a gel during deformation, and
characterizes its stiffness. At 3 % (w/v), supernatant fractions did not form stable foams and gels at
pH 3, 5, 7, and 10, except for gelation for A. domesticus at pH 7. At 30 % w/v, gels at pH 7 and pH
10 were formed, but not at pH 3 and pH 5.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 25
In conclusion, the insect species studied have potential to be used in foods due to: 1) absolute
protein levels; 2) protein quality; 3) ability of forming gels.
About the presenter
Miss Yi Liya is currently finishing her PhD at Food Quality & Design group of
Wageningen University. Her PhD project is on extraction, purification and
characterization of protein and lipid fractions from selected insect species. She
obtained her BSc & MSc degree, and worked as a PhD all in Wageningen
University (2005-2014). She likes playing badminton and basketball. She plays
piano for more than ten years.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 26
Antibacterial effect of LEDs on Salmonella spp. in orange juice – Influence of temperature and irradiance
Vinayak S. GHATE, YUK Hyun-Gyun*, and ZHOU Weibiao
Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
* Corresponding author: [email protected]
Abstract
LEDs have emerged as a novel means for ensuring food safety. They work on the principle of
photodynamic inactivation, bringing about bacterial death through the cytotoxic effect of reactive
oxygen species. Fruit juices, which are sold from dispensers in food courts are prone to post-
processing contamination either as a result of contaminated equipment or poor hygiene of food
handlers. Hence, their safety is of paramount importance. In this study, the antibacterial effect of 460
nm LEDs was studied on Salmonella spp. was studied at three temperatures (4, 12 and 20 °C and
three irradiances (92, 148 and 255 mW/cm2). The total dosage incident on the cultures was 4500 J. It
was observed that the temperature as well as the irradiance influenced the inactivation of the
pathogens. A lower temperature resulted in a higher inactivation. A similar trend was observed with
the irradiance. The colour of the orange juice samples during the illumination was monitored using a
Hunter colorimeter and certain changes in the colour were observed and quantified. Different
mathematical models such as the linear model, the Weibull model and the reparameterized Gompertz
model were also evaluated for their fit to the inactivation curves. Finally, a secondary model was
developed which related the influence of temperature and irradiance on the antibacterial effect of the
LEDs.
About the presenter
Mr Vinayak S. Ghate is a PhD student at the National University of Singapore. He
completed his B. tech. in Food Engineering & technology from the Institute of
Chemical Technology, Mumbai in 2011. He will be graduating next year.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 27
Novel processing technologies and novel protein foods
Geraldine RUIZ1, Marcel MINOR, Markus STIEGER, and Tiny VAN BOEKEL*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
2 Food Bio-based Reseach, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
* Corresponding author: [email protected]
Abstract
The global population is rising, so is the demand for protein foods. Traditional protein-rich products,
like meat and dairy are not very sustainable and not always healthy, and protein-enriched products
used in sports nutrition are not very appealing and targeted at too small population groups. This is
why, more recently, tasty and healthy protein-enriched products for the mass population have been
developed and the market for this is booming. Such protein-enriched products need to be processed in
a way to be safe to consume. Traditionally, this can be done by thermal treatments. However, as it is
known from other foods, those treatments may negatively affect food quality parameters such as
nutritional and sensory properties. This is why much research has gone into novel processing
technologies that use no or low heat to reduce the impact on food quality while achieving the same
food safety and shelf-life as traditional thermal treatments. One of these novel technologies is high
pressure processing.
The aim of this study is to evaluate the effects of high pressure and heat processing on quality
properties of protein-rich food systems using different protein sources.
The effects of high pressure and heat processing on quality attributes of liquid and possibly semi-
solid food model systems containing protein and sugar will be investigated and causes on a molecular
and microscopic level will be searched for. The quality attributes examined include viscosity, colour
(browning), acidity, protein digestibility and, possibly, overall sensorial quality.
About the presenter
Miss Geraldine Ruiz is a PhD employed by the Food & Biobased Research, a
business affiliated to Wageningen University and Research. She works on the
impact of high pressure processing on protein properties and on quinoa protein
extraction and characterisation (two separate projects). She is German, studied in
France, Scotland and the Netherlands in the Medical, Biological and Food
Sciences and has completed internships in hospitals and in the food industry. She enjoys cooking,
eating, sporting, socialising and exploring new cultures.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 28
Effects of high-intensity 405 nm light emitting diode on inactivation of Gram-negative foodborne pathogens
KIM Min-Jeong1, Marta MIKŠ-KRAJNIK1,2, Amit KUMAR1, and YUK Hyun-Gyun1 *
1 Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543
2 Chair of Industrial and Food Microbiology, Faculty of Food Science, University of Warmia and Mazury in Olsztyn, Plac Cieszyński 1, 10-726 Olsztyn, Poland
* Corresponding author: [email protected]
Abstract
A light emitting diode (LED) has recently received increased attention due to its antibacterial effect.
Some researchers have reported that 405 nm LED had bactericidal effect, demonstrating the potential
of novel food preservation technology. However, little information is available on its effectiveness on
foodborne pathogens and its antibacterial mechanism. The aim of this study was to investigate the
antimicrobial effect of LED on the selected Gram-negative foodborne pathogens and to elucidate its
antibacterial mechanism by determining bacterial membrane damage.
Escherichia coli O157:H7, Salmonella Typhimuirum, and Shigella sonnei were treated with 405 nm
LED. A 10 ml volume of bacterial suspension (about 108 CFU ml-1) was exposed to 1,067 J cm-2 of
LED at 4°C. The irradiance was 35±5 mW cm-2. The percent of sublethal injuries were determined
by plating tryptic soy agar (TSA) and TSA including 2-3% NaCl and 1% bile salts as selective agents,
respectively. A Live/Dead® Cell Viability assay was used to examine the membrane damage using
fluorescence microscopy. E. coli O157:H7, S. Typhimuirum, and S. sonnei were inactivated by 1.0-,
2.0-, and 0.8-log CFU ml-1, respectively, at 1,067 J cm-2. Regardless of bacterial strain and selective
agent, longer exposure time resulted in an increase in the injury percent, indicating that LED-treated
cells became more susceptible to NaCl and bile acid than untreated control cells. A Live/Dead® Cell
Viability assay also clearly showed that LED-treated cells underwent loss of the physical integrity of
the membrane, whereas untreated cells were intact.
These results indicate that 405 nm LED might be effective to inactivate the selected Gram-negative
foodborne pathogens in foods, exhibiting the potential of novel food preservation technology. In
addition, this study suggests that the antibacterial effect of the LED would be due to the membrane
damage.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 29
About the presenter
Miss Kim Min-Jeong is currently a PhD candidate at the Food Science and Technology Programme
at the National University of Singapore. She graduated from Kyungnam University
(Republic of Korea) with a Bachelor of Applied Science and Master of Applied
Science in Food Science and Technoogy. She started her PhD studies in 2012,
working on food microbiology and safety, with a focus on inactivating foodborne
pathogens with light emmiting diode (LED), under the supervision of Assistant
Professor Yuk Hyun-Gyun.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 30
Production and valorisation of high quality proteins from insects
Renske JANSSEN1 2, Jean-Paul VINCKEN, Catriona LAKEMOND, Vincenzo FOGLIANO, and Tiny VAN BOEKEL*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
2 Food Chemistry Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
* Corresponding author: [email protected]
Abstract
There is a growing demand for proteins to feed the increasing world population. It is estimated that
the world population in 2050 will be around 9 billion and that 70% more food is necessary. An
alternative protein source can be insects, since the nutritional value is comparable to conventional
meat, and its production is more sustainable. Although 80% of the world population consumes insects
already occasionally, consumers in most Western countries appear to dislike such protein sources.
This might change when insect protein is added as a food ingredient, so that the insect is not
recognisable as such.
To use the insect proteins as a food ingredient, it is necessary to maintain their techno-functional
properties. For this, protein extraction from the whole insect under mild extraction conditions is
essential to preserve the characteristics of the native protein. Preliminary experiments have shown that
substantial enzymatic browning occurred during grinding of insects. Enzymatic browning is caused by
oxidation of phenolic compounds and subsequent condensation. This enzymatic reaction is catalysed
by polyphenol oxidase (PPO), which can be activated in insects as a defence reaction during
wounding and it plays a role in the exoskeleton formation. The browning can influence the techno-
functional properties, like solubility and digestibility. So efficient inhibition is necessary in order to
prevent this.
The objective of this research is to extract and characterize the water-soluble proteins efficiently
from insects, while preventing browning. This will be done by developing an efficient protein
extraction method to obtain the soluble proteins. Different methods will be investigated for the
inhibition of enzymatic browning.
About the presenter
Miss Renske Janssen was born in Rotterdam, the Netherlands. She did her
bachelor and master in Food Technology at the Wageningen University with
specialization in ingredient functionality. For her Masters, she did an internship at
Nestlé research centre in Lausanne, Switzerland. Her thesis was performed in the
laboratory of Food Chemistry on the inhibitory effect of plant extracts on
polyphenol oxidase from mushroom and potato. She is now a PhD student at Food Quality and Design
and Food Chemistry on the extraction of proteins from insects and prevention of enzymatic browning.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 31
Temperature adaptation alters Salmonella Enteritidis heat/acid resistance, membrane lipid composition and stress/virulence related gene expression
YANG Yishan1, KHOO Wei Jie1, ZHENG Qianwang1, CHUNG Hyun-Jung2, and YUK Hyun-Gyun1,*
1 Food Science & Technology Programme, Department of Chemistry, National University of Singapore, Singapore
2 Department of Food & Nutrition, Inha University, Incheon, Republic of Korea
* Corresponding author: [email protected]
Abstract
The influence of growth temperature (10-42°C) on the survival of Salmonella Enteritidis during
heat treatment (54-60°C) and in simulated gastric fluid (pH = 2.0), on the membrane lipid
composition, as well as on stress-/virulence-related gene expression was studied. The results showed
that cells incubated at 37°C had the greatest acid resistance; while cells incubated at higher
temperature exhibited increased heat resistance. A decrease in the ratio of unsaturated to saturated
fatty acids (USFA/SFA) was observed as the growth temperature increased. Compared to the control
cells grown at 37°C, the expression of rpoS was 16.5- and 14.4-fold higher in cells cultivated at 10
and 25°C, respectively; while the expression of rpoH was 2.9-fold higher in those cultivated at 42°C.
The increased expression of rpoH and the decreased USFA/SFA correlated with the greater heat
resistance of bacteria grown at 42°C; while the decreased expression of rpoS at 42°C might contribute
to the decreased acid resistance. Virulence related genes-spvR, hilA, avrA-were induced in cells
cultivated at 42°C, except sefA which was induced in the control cells. This study indicates that
environmental temperature may affect the virulence potential of S. Enteritidis, thus temperature
should be well controlled during food storage.
About the presenter
Ms Yang Yishan is a PhD student under supervision of Dr. Yuk Hyun-Gyun. She
received her B.Sc and M.Eng degree from Department of Food Science and
Technology in Huazhong Agricultural University, China. Her research work focuses
on the responses of Salmonella Enteritidis under various adverse stress conditions.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 32
Interplay of consumer psychology, product properties and sensory perception on the consumer acceptance of insects as food
Grace TAN Hui Shan1, 2, Catriona LAKEMOND, Markus STIEGER, Arnout FISCHER, and Hans VAN TRIJP*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
2 Marketing & Consumer Behavior, Human Nutrition (Sensory Science), 6700 AA Wageningen, the Netherlands
* Corresponding author: [email protected]
Abstract
Eating is a frequent activity that is strongly motivated by pleasure, and hence dilemmas often arise
in food choice decisions where the immediate pleasure of consuming a food could conflict with the
longer term rewards of healthy and sustainable eating. Currently, there is great interest in the West
regarding the potential of insects as a source of sustainably produced protein-rich foods. Efforts to
promote the consumption of insects in the West have largely focussed on the environmental and
nutritional advantages over traditional meat sources, but despite strong public interest, the arguments
presented are insufficient to convert consumers who are unaccustomed to eating insects. This is
largely due to the unfamiliarity of insects as food but also the familiarity with them as pests and
disease that result in the elicitation of disgust at the prospect of consumption. In contrast, in insect-
eating cultures, consumers eat insects for the pleasure of taste and are specific in their preferences for
the various species, preparation methods and eating contexts.
The basis of acceptance and rejection of insects as food was explored in a cross-cultural focus group
study with consumers in Thailand, where insects are part of the cuisine, and in The Netherlands,
where insects are generally not considered food. It was found that while extrinsic factors such as
healthiness and sustainability arouse interest, they do not overcome the psychological barriers to
consuming inappropriate and unfamiliar foods. Prior exposure with food items leads to preferences
and expectations towards what is appropriate and tasty. Prior experience also influenced whether
evaluations were based on actual tasting experiences or on insect- and appearance-related associations,
which tended to be very negative. In addition, items that are normally perceived to be tasty could be
rejected if the combination is not considered appropriate. The outcomes of this study showed that the
basis of perception and evaluation of insects as food are very different depending on the degree of
prior experience and cultural background, and demonstrated that the promotion of insects should not
solely focus on communicating the benefits of consumption but should pay due attention to creating
products that suit consumer expectations in their own cultural context.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 33
About the presenter
Miss Grace Tan Hui Shan is a 3rd year PhD student in the sensory and consumer
sciences. She works on understanding the cultural and psychological mechanisms
underlying the acceptance and rejection of insects as food, and how the successful
use of product design could help to overcome the barriers towards new foods. She is
originally from Singapore and did her Bachelors in Food Science and Technology at
the National University of Singapore, and a double masters in Nutrition and Health at Wageningen
University and Food Technology at the University of Copenhagen, where she specialized in sensory
science and eating behaviours. She loves to explore food cultures and to experience tastes from
around the world.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 34
Optimization of real-time PCR method combined with immunomagnetic separation for detecting healthy and heat-injured Salmonella
Typhimurium on raw duck wings
ZHENG Qianwang1, YANG Yishan1, KIM Min-Jeong1, Marta Mikš-Krajnik1,2, and YUK Hyun-Gyun 1,3,*
1 Food Science & Technology Programme, Department of Chemistry, National University of Singapore, Singapore
2Chair of Industrial and Food Microbiology, Faculty of Food Science, University of Warmia and Mazury in Olsztyn, Plac Cieszyński 1, 10-726 Olsztyn, Poland
3National University of Singapore (Suzhou) Research Institute, No. 377 Linquan Street, Suzhou Industrial Park, Suzhou, Jiangsu, China 215123
* Corresponding author: [email protected]
Abstract
This study investigated a rapid detection method combining real-time PCR and immunomagnetic
separation (PCR-IMS) to determine healthy and heat-injured Salmonella Typhimurium on duck.
IMS was optimized on Salmonella cells with different reaction and separation times. Three Taqman
primers (Sal, invA and ttr) were evaluated to optimize the PCR protocol. The optimized PCR-IMS
was compared with ISO and PCR method by analyzing raw duck wings with healthy and heat-injured
Salmonella cells at low innoculum levels, followed by validating with naturally contaminated samples.
Under optimal IMS conditions (30 min reaction and 3 min separation), 85 and 64 % of Salmonella
were captured from pure culture and food suspensions. Sal showed lower LOD (103 CFU/mL) and
higher PCR efficiency (94.1%) than invA and ttr, therefore Sal was chosen for further experiments.
The optimized PCR-IMS method was significantly better to detect healthy Salmonella after 7-h
enrichment than PCR method alone, however there was no significant difference between two
methods with longer enrichment time (14 h). The diagnostic accuracy of PCR-IMS was shown to be
97.5% through the validation study.
The optimized PCR-IMS method could provide a sensitive and rapid detection for Salmonella.
However, a longer enrichment time should be needed for reliable detection of heat-injured cells.
About the presenter
Ms Zheng Qianwang received her bachelor in the Department of Biological
Science, Sun Yat-Sen University (Guangdong, China) in 2011. She started her PhD
in Food Science and Technology in NUS in the same year. Currently, she is under
the supervision of Assistant Professor Yuk Hyun-Gyun, and mainly focus on
foodborne pathogen rapid detection.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 35
Dynamic texture perception and food oral breakdown
Marine DEVEZEAUX DE LAVARGNE1 2, Markus STIEGER, and Tiny VAN BOEKEL*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
2 Top Institute Food and Nutrition, Human Nutrition (Sensory Science) (WUR)
* Corresponding author: [email protected]
Abstract
Texture perception depends on oral processing as the food structure is constantly modified during
eating until it forms a ready to swallow paste called food bolus. In order to obtain a full understanding
of texture perception, food structure, food breakdown in mouth, eating behaviour and physiology
must be controlled and/or measured in parallel.
Texture perception in mouth depends on the food structure and its contact with the oral cavity. Food
structure can be controlled in order to obtain desired sensory textures, however this structures are
modified during oral processing and are hardly correlated with perception of chew down texture
attributes. The main phenomenon occurring during oral processing are the decrease in structure of the
food by comminution during chewing and the increase in lubrication by salivation. In order to
understand the changes in food texture, the properties of the forming bolus can be analysed. A wide
range of analyses on spit out bolus exist in literature from measuring particle size to saliva content.
Due to the complexity of food structures, a wholesome understanding is difficult to obtain and model
foods such as gels are usually designed in investigating texture perception. Mixed gels containing
several gelling agents can be used to control structural and microstructural aspects of the food.
Emulsion filled gels can be used to investigate perception of fat related attributes. In this PhD,
emulsion filled gels with varying fracture properties were designed, breakdown and bolus properties
were analysed on spit out bolus and linked to dynamic texture perception. Measuring the temporal
aspect of sensory texture can be done with the separation between first bite, chew down and after-feel
texture attribute in a quantitative descriptive analysis (QDA). More dynamic methods such as
sequential profiling and temporal dominance of sensations (TDS) have recently been developed. In
this work, several methods were used separate or in combination to obtain a wholesome sensory
profile of foods.
In this PhD work, food gel structure impact on breakdown was investigated, moreover the
properties of the food bolus were linked to dynamic texture perception. It was shown that some bolus
properties explain the perception of chew down texture attributes such as graininess or melting.
Creaminess is a multimodal sensory attribute depending on several bolus properties. Other work on
inter-individual differences on texture perception showed that eating speed influenced perception of
texture attributes perceived towards the end of mastication.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 36
About the presenter
Miss Marine Devezeaux de Lavargne is a 4th year PhD student in the FQD
department and as part of the sensory group of the Human Nutrition department of
Wageningen UR. Her PhD combines the fields of food structuring, sensory science
and human physiology. She studied Food Science Engineering in France in
AgroParisTech where she finalized her studies by a double-degree with Wageningen
University. She enjoys travelling and trying all sorts of new foods.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 37
Masticatory effort and bolus formation during oral processing of bread in relation to its physicochemical properties
GAO Jing, Jocelyn WONG Xue Yan, and ZHOU Weibiao*
Food Science and Technology Programme, Department of Chemistry, National University of Singapore, Science Drive 3, Singapore 117543
* Corresponding author: [email protected]
Abstract
Food structure is dramatically modified when it undergoes oral processing. The breakdown of food
structure and formation of bolus are determined both by intrinsic food properties and extrinsic
individual physiological differences. This study aimed to investigate the role of physicochemical
properties of bread on its disintegration and human masticatory behavior during oral processing.
Three types of bread, i.e. baked white bread, steamed bread, and French baguette, with distinct crumb
grain feature were evaluated. Single human panelist masticated the bread freely until ready to swallow
and then spat out the bolus. Collected bolus was analyzed for its density, saliva impregnation and
particle size distribution. Muscle activity of the evaluator’s muscles (i.e. masseters and anterior
temporalis) was monitored using surface electromyography (SEMG). Results showed that the total
chewing duration was significantly shorter and the number of chewing cycles was significantly lesser
for the steamed bread compared to the baked bread and the baguette. The baguette exhibited the
largest SEMG amplitude and muscle work per chew, followed by the baked bread and the steamed
bread. These results suggested that the steamed bread required the least amount of chewing effort to
form a safe-to-swallow bolus, followed by the baked bread and the baguette. Results from bolus
characterization showed that baguette bolus had the greatest amount of saliva impregnation whereas
steamed bread bolus had the largest median particle size, indicating a different level of lubrication and
mechanical breakdown of the three types of bread. Specific volume of bread was found to be
significantly correlated with chewing cycle, saliva impregnation level, and median particle size. Our
study demonstrated that bread with different physicochemical properties required a different level of
oral processing, leading to different levels of disintegration and lubrication after chewing which may
have a profound impact on its subsequent digestion in stomach and small intestine.
About the presenter
Ms Gao Jing is currently a PhD student at the Food Science and Technology
Programme in the National University of Singapore. She obtained her Bachelor of
Applied Science (with Honours) degree from the same programme in 2012. She
started her postgraduate study early 2013 under the supervision of Professor Zhou
Weibiao, working on the study of bread structure and its digestion.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 38
Oral coatings, tastant migration and perception
Sara Marina RODRIGUES CAMACHO1 2, Markus STIEGER, and Kees DE GRAAF*
1 Food Quality & Design Group, Wageningen University & Research Centre, 6700 AA Wageningen, the Netherlands
2 Top Institute Food and Nutrition, Human Nutrition (Sensory Science) (WUR)
* Corresponding author: [email protected]
Abstract
Oral coatings are residues remaining on oral surfaces after the consumption of foods and beverages.
Oral coatings have been shown to influence taste and aroma perception. Madrigal-Galan and
Heymann observed a decrease in intensity of several wine sensory attributes, such as astringency, bell
pepper, and oak flavour, when the wine was evaluated after eating cheeses. It was hypothesized that
the decrease in intensity might be caused by an oral coating of fat in the oral cavity, formed by the
cheese. Furthermore, de Wijk suggested that fat containing oral coatings lubricate the movement of
the food bolus on the oral tissue leading to lower intensities of perceived dryness and roughness and
higher intensities of creaminess of custards2. Although the influence of oral coatings on sensory
perception has been studied by several authors, there is only very little information available on the
composition and structure of oral coatings.
The aim of this project was to investigate the physical and sensory properties of coatings on the
tongue formed by oil/water (o/w) emulsions as a model system for beverages. In vivo fluorescence
measurements were used to quantify the fraction of oil (moil/Atongue) deposited on the tongue in
relation to dynamic sensory perception. In vivo fluorescence method provides a direct measure of oral
coatings deposition, without damaging any of its components and gives a spatial.
Different o/w emulsions were prepared to investigate the influence of several factors (e.g. oil
content, protein type and content) on the deposition and clearance of oral coatings. Curcumin was
added as a hydrophobic fluorescent marker to all the samples. Twenty subjects processed orally each
sample for 30s, in triplicate. The fluorescence intensity of the oral coating was measured at eight time
points, in the front and back part of the tongue. Simultaneously, subjects rated the perceived intensity
of coating related attributes.
For every sample, the oil fraction was significantly higher on the back part of the tongue than on the
front part. The oil fraction initially deposited on the tongue was affected by the oil composition of the
o/w emulsion. The type and amount of protein used in the emulsions had a significant effect on the
deposition and clearance of the coating. This project unravels new insights in the oral processing of
emulsions, and demonstrates the potential of in vivo fluorescence to study food behaviour in mouth.
Joint Symposium on Food Science and Technology between NUS and WUR 29 October 2014, National University of Singapore
pg. 39
About the presenter
Miss Sara Rodrigues Camacho is a PhD student on a project financed by TI Food
and Nutrition, and is working within the Divisions of Food Quality and Design and
Human Nutrition (Sensory Science Group) of Wageningen University, the
Netherlands. Sara was born in a small island called Madeira, in Portugal, known as
the “Pearl of the Atlantic”. She made her bachelor and master on Biological
Engineering in the Technical University of Lisbon, Portugal. Sara really enjoys to explore new places,
meet new people and loves animals.