Yeasts and the Fermented Food Renaissance
Graham H Fleet
Food Science
School of Chemical Engineering
UNSW Australia
Sydney
Australia, 2052
Fermented foods have natural origins and purpose
• Traditional processes that gave :
• preservation of foods with safety , sensory appeal, psychological enjoyment
• Scientific understanding gave :• industrialized, mass production,
starter cultures, commercial value
Bread, Cheese Yogurt, Beer ,
Wine etc
Traditional fermented foods
One Third !!!
Extensive field of research• Fermented Foods of the
World-- Campbell-Platt 1987
• Handbook of Food and Beverage Fermentation Technology--Liu et al 2004
• Handbook of Fermented Functional Foods--Farnworth 2008
• Fermented Foods and
Fermented foods--- since 1980s
Scientific understanding
• Fermented Foods and Beverages of the World--Tamang and Kailaspathy 2010
• Perspectives on Global Fermented Foods-- Soni and Dey 2014
• Oxford Handbook of Food Fermentations-- Bamforth and Ward 2014
Commercialization
New interest in fermented foods and beverages
McGee, H ( 2013) Nature, 504: 372-374 Despain, D ( 2014) Food Technology (Sept ) 39-45
Process advantages
Natural, healthy minimal process; not seen as processed foods; indigenous microorganisms; “ backslopping”, starter cultures
Ecologically sustainable
Products with regional character, diversity - added value
What is driving the fermented food renaissance ??
value
Process simply fine-tuned ( eg. temperature, strain) to give product diversity
Application to a diversity of raw materials– meats , cereals, fruits, vegetables
Western awareness of indigenous fermented foods in Africa , Asia, Central and South America
Health and well being benefits• Nutritional: enriched
proteins, vitamins; decreased anti-nutrients; increased bio-availability
What is driving the fermented food renaissance ??
HOW ??
Production of biogenic substances
: antioxidants, phenolics, bioactive
peptides, GABA, enzymes to degrade bio-availability
• Natural functional foods : diversity of positive impacts on gastrointestinal, cardiovascular, immune and central nervous systems
enzymes to degrade allergens, toxins
Impact on gut microbiota (microbiome)
Direct or indirect , new probiotics
The nutrition, health and gut microbiota linkage
Human diet
Gut
*Depression*Anxiety
*Cognitive function*Obesity*Type 2 Gut
microbiota
Health
*Type 2 diabetes*Immune function*Cancer
*Cholesterol*And so on
Ley R et al 2006. Human gut microbes associated with obesity. Nature 444, 1022
Clemente J et al 2012. The impact of the gut microbiota on human health; an integrative view. Cell 148, 1258
Kau A et al 2011. Human nutrition, the gut microbiome and the immune system. Nature 474, 327
David L et al 2014. Diet rapidly and reproducibly alters the human gut microbiome. Nature 505, 559
Cryan J and Dinan T 2012. Mind altering microorganisms: the impact of gut microbiota on brain and behaviour. Nature Reviews
The scientific evidence increases
of gut microbiota on brain and behaviour. Nature Reviews Neuroscience 13, 701
Derrie M at al 2015. Fate activity and impact of ingested bacteria within the human gut microbiota. Trends in Microbiology 23, 354
Lang J et al 2014. The microbes we eat--.PeerJ, 2:e569
Gobbetti M et al 2010. Functional microorganisms for functional food quality. Crit Rev Food Science and Nutrition 50, 716
Selhub E et al 2014. Fermented foods, microbiota and mental health: ancient practice meets nutritional psychiatry. J Physiological Anthropology 33, 2
Marsh A et al 2014 Fermented beverages with health promoting potential-. Trends in Food Science and Technology 38, 113
What about yeasts and fermented foods??
• Present in a diversity of other fermented foods, along with bacteria , filamentous fungi
• What is their contribution to product quality, functionality?
• What happens to yeasts during ingestion and digestion?ingestion and digestion?
• What is the occurrence and significance of yeasts in the human gut??
Bacterial bias !!
• Alcoholic fermentation-ethanol , flavour volatiles
• Hydrolysis of starch, protein, lipids, pectins
• Utilization of organic acids-citric, malic, lactic
• Degradation of anti-nutrients-phytic acid
• Enrichment of vitamins- folic acid, B vitamins
• Enrichment of antioxidants
• Autolytic products
Functional attributes of yeasts in fermented foods
• Autolytic products
• Stimulation of bacterial growth
• Inhibition of bacterial, fungal growth
• Adsorption, degradation of toxic substances,
• Probiotic effects
Moslehi-Jenabain, Pedersen, Jespersen. 2010. Nutrients 2: 449-473
Fermented milk products with high populations ( 106-108 cfu/g) of
yeasts- cheeses, kefir, koumiss, aryan, rob, amasi etc
Debaryomyces hansenii ; Yarrowia lipolytica; Kluyveromyces marxianus; Saccharomyces
cerevisiae
Saccharomyces cerevisiae, Kluyveromyces marxianus, Kazachstania unispora, Dekkera anomala, Issatchenkia
occidentalis; Torulaspora delbrueckii
Garofalo et al 2015 Food Microbiol 49:123Marsh et al 2013 FEMS Microbiol Let 348:79
Kefir: expanding market; diversity of milks; apply granules to fruit juices
Zeynep B et al 2011 Review: functional properties of kefir. Crit Rev Food Science and Nutrition, 51, 261
• Health beverage since 2000 years in China
• SCOBY-symbiotic culture of bacteria and yeast
• Slightly sweet, acidic ( acetic),mild ethanolic flavour
• Acetic, lactic, gluconic acids,
Kombucha—fermented tea ( tea fungus)
(nata de coco)
• Acetic, lactic, gluconic acids, pH 2-3
• Main bacteria: (acetic acid bacteria , lactic acid bacteria) Komagataeibacter xylinus ( Acetobacer xylinum), Gluconoacetobacter, Acetobacter, Lactobacillus, Lactococcus spp
Culture and culture independent studies
• Zygosaccharomyces ( Z. lentus, Z bisporus, Z bailii);
• Dekkera bruxellensis; D anomala
• Schizosaccharomyces
Kombucha yeasts
• Schizosaccharomycespombe
• Torulaspora delbrueckii
• ( 106-108 cfu/g)
• Teo et al 2004 Int J Food Microbiol.95, 119
• Marsh et al 2014 Food Microbiol.38,171
Yeasts 106-108 cfu/ml
• Saccharomyces cerevisiae
• Schizosaccharomyces pombe
• Saccharomycodes ludwidgii
• Zygosaccharomyces spp
Traditional alcoholic beverages: palm wines, fruit wines, beers—high populations of yeasts
Lactic acid bacteria, acetic acid bacteria, Zymomonas mobilis—106-109 cfu/ml
Some microorganisms of natural/indigenous fruit juice fermentations
• Pineapple : Pichia guilliermondii, Hanseniaspora uvarum, Lactobacillus plantarum ( di Cagno et al 2010; Chanprasartsuk et al 2010)Chanprasartsuk et al 2010)
• Gabiroba: Candida quercitrusa, Issatchenkiaterricola, Saccharomyces cerevisiae, lactic acid bacteria ( Duarte et al 2009)
• Masau: Issatchenkia orientalis, Pichiafabianii, Saccharomyces cerevisiae, Lactobacillus plantarum etc ( Nyanga et al 2007)
Growth of yeasts during indigenous pineapple juice fermentation ( Chanprasartsuk 2008 PhD Chulalongkorn Uni.)
Hanseniaspora uvarum ; Pichia guilliermondii, dominant yeasts ; absence of Saccharomyces cerevisiae
• Which microbial groups or species are important ??
• What is the strain influence??>
• Which ones are essential ??
• Which ones cause spoilage?
Untangling the complex ecology
Fermented Food
Yeasts Fungi
Bacteria
Bacteriophages
Microbial interactions
Wholistic, integrative approach
Raw materials Process of
Microbial
ecologyQualitative data
Quantitative dataPhysiology
BiochemistryGenomics
( strain level)
Properties
ChemicalPhysicalSensory Safety
Functional
Process of production
Product quality criteria
( strain level)
Analytical
toolsMicroscopy
CultureMolecular culture-
independentMALDI TOF
Analytical toolsGC/LC MS
NMRElectron
microscopy
PLANTATION
DRYING
Yeasts are essential for cocoa fermentation Ho et al 2014 Int J Food Microbiol. 174: 72-87
Yeasts: Hanseniaspora , Pichia, Saccharomyces,
Kluyveromyces spp
Lactic acid bacteria: Lactobacillus , Leuconostoc,
Lactococcus spp
Acetic acid bacteria:
FERMENTATION(3-6 DAYS)
HARVEST PODS
REMOVE BEANS AND PULP FROM
POD
Acetic acid bacteria: Acetobacter, Gluconobacter spp
Selective inhibition studies:
NatamycinNisin-Lysozyme
0
2
4
6
8
10
0 1 2 3 4 5 6
Log
10
(cf
u/g
be
an
)
Fermentation time (day)
The growth of bacteria during
spontaneous fermentation
Lactobacillus plantarum Lactobacillus fermentum
0
2
4
6
8
10
0 1 2 3 4 5 6
Log
10
(cf
u/g
be
an
)
Fermentation time (day)
The growth of bacteria during yeast-
inhibited fermentation
Lactobacillus plantarum Lactobacillus fermentum
Cocoa fermentation in presence of natamycin (no yeasts)
Lactobacillus plantarum Lactobacillus fermentum
Gluconobacter sp. Acetobacter pasteurianus
Lactobacillus plantarum Lactobacillus fermentum
Gluconobacter sp. Acetobacter pasteurianus
* The beginnings to 1900s--- indigenous fermentations, wild largely uncontrolled
• * 1900 to 2000---controlled, single starter
The wine and beer stories continue
What next controlled, single starter culture fermentations, progressing to mixed starter cultures
• * 2000--- return to indigenous fermentations but controlled based on scientific understanding
What next ???
Unexpected consequences of yeast fermented food!!
Tape KetanIndonesia
Ardhana M and Fleet G. 1989. Int J Food Microbiol. 9: 157-165
Thank you
Food Microbiol. 9: 157-165
Fermented fruits
Fermented cereals- wheat , maize, sorghum, millet, rye, rice etc
Fermented legumes- soy beans, chick peas, lupins etc
Fermented vegetables
Fermented milks
The diversity of fermented foods
Moving outside the Fermented milks
Fermented meats, poultry, sea foods
Lactic acid fermentation, Alcoholic fermentation, Acetic acid/vinegar fermentation, Alkaline fermentation. OTHERS
outside the box
0
2
4
6
8
10
0 1 2 3 4 5 6
Log10 (cfu/g bean)
Fermentation time (day)
Total bacterial count during cocoa bean fermentation
Control Yeast inhibition
Cocoa fermentation in the absence of yeasts—no chocolate flavour !!
Control Yeast inhibition
0
2
4
6
8
10
0 1 2 3 4 5 6
Log
10
(cf
u/g
be
an
)
Fermentation time (day)
The growth of bacteria during
spontaneous fermentation
Lactobacillus plantarum Lactobacillus fermentum
Gluconobacter sp. Acetobacter pasteurianus
0
2
4
6
8
10
0 1 2 3 4 5 6
Log
10
(cf
u/g
be
an
)
Fermentation time (day)
The growth of bacteria during yeast-
inhibited fermentation
Lactobacillus plantarum Lactobacillus fermentum
Gluconobacter sp. Acetobacter pasteurianus
Hanseniaspora,
Kloeckera,
Candida,
Metschnikowia,
Pichia,
Yeasts and the alcoholic fermentation
4
6
8
Candida spp.
Saccharomyces cerevisiae
Ye
ast
co
un
t (L
og
10
ce
lls/m
l)
Kluyveromyces,
Saccharomyces
cerevisiae,
Saccharomyces
bayanus
Successional growth of species and strains- also for “starter”
fermentations
0
2
0 2 4 6 8 10
Fermentation time (days)
Kloeckera/Hanseniaspora sppYe
ast
co
un
t (L
og
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