9. Necesidades y oportunidad investigacion - Teixeira

University of Minho

Institute for Biotechnology and Bioengineering

Centre for Biological Engineering

J. A. [email protected]

Dairy workshop

Lugo, 26 October 2010

Necessidades e oportunidades de investigação no sector lácteo

Dairy research –

opportunities and needs

Universidade do MINHO

Braga

Guimarães

Introduction

Overview

Consumer demands for more convenient and varied milk products

Extended shelf‐life of milk and milk products

Healthier foods

Sustainable and clean processes

Severity of the traditional processing

food processing technologies

Production of high volume effluents

Introduction

Development of thermal and non‐thermal technological

approaches capable of substituting the traditional

well established preservation processes.

Development of process for valorization of the effluents

Introduction

•

Dielectric heating•

Radio frequency

•

Microwave heating•

Ohmic heating

•

High pressure•

Pulsed electric fields

•

New packaging systems

Novel and emergent thermal technologies have been developed and can replace the traditional heating

methods that rely on conductive and convective heat transfer

Ohmic

heating

Why ?

:•

Heat is generated directly inside the food and this has direct

implications in terms of both energetic and heating efficiency

Ohmic Heating

Ohmic Heating

Heat transfer (cond./conv.)

Mass transfer (diffusion)

Momentum transfer

Internal heat gen.Mass transf. (conv.)Heat transf. (conv.)

Heat transfer (cond./conv.)

Flow eventually

entering the ohmic heater

(zero, if in batch

operation)

Flow eventually leaving the

ohmic heater (zero, if in

batch operation)

Limit of the heating volume

LIQUID PHASE

SOLID PARTICLE

Electrodes

Internal heat gen.Mass transf. (diff.)Heat transf. (cond.)

60 kW continuous ohmic heater (pilot‐scale)

Ohmic Heating

Pilot‐scale continuous ohmic

heater

Overall the major benefits claimed for ohmic heating technology are as follows:

Ohmic Heating

Temperature required for HTST processes can be achieved very quickly;

Suitable for continuous processing without heat transfer surfaces;

Uniform heating of milk with faster heating rates;

Electric fields may provide a non‐thermal killing effect over some microorganisms, reducing

the time for their inactivation

Reduced problems with of overheating of the product compared to conventional heating;

No residual heat transfer after the current is shut off, and very low heat losses;

Low maintenance costs (no moving parts) and high energy conversion efficiencies;

Environmentally friendly system.

Applications:

Possible applications include most of the heat treatments such as blanching, evaporation, dehydration ,fermentation as well as

pasteurization and sterilization.

Processing of low‐acid particulate product in a can and pasteurized liquid egg

Innovative applications, such as fruit puree

Meat cooking

Milk pasteurization

Ohmic Heating

Microbial InactivationTime to reduce 90 % of a microbial population (D values) is faster when ohmic

heating is applied;

Effects on EnzymesPresence of an moderate electric does not cause an enhanced inactivation of Alkaline Phosphatase

(ALP) and β-Galactosidase

(β-GAL).

Effects on Milk LipidsOhmic

HTST pasteurization does not promote modification of Free

Fatty Acids (off-flavour) in goat milk, when compared with conventional HTST pasteurization;Composition of fat was not altered by the presence of electric fields during ohmic

heating.

Ohmic Heating

Effects on Proteins

Less protein denaturation

→

problems associated with heat transfer surfaces are eliminated (volumetric heating)

Non‐thermal effects: presence of electric fields can promote conformational disturbances on tertiary protein structure (due to

rearrangement of hydrogen bonds, hydrophobic interactions, and ionic bonds)

Less association or aggregation of milk proteins

Ohmic Heating

Important consequences on the acid‐induced gelation

properties of milk

Ohmic Heating

•

Research is required in the following areas:•

To elucidate on the relative importance of electric current properties

and the corresponding

temperature

values

on

the

killing

of

microbes

and

in

particular

resistant

structures

(e.g.,

spores).

•

To

characterize

the

effect

of

OH

on

the

nutritive,

organoleptic, and

functional

properties

of

dairy foods.

•

To

develop

methods

that

will

allow

for

a

more

precise

mapping

of

temperatures

on

foods

submitted to OH.

•

To develop models that can adequately describe ohmic

processing of foods.

•

To

implement

these

models

so

that

an

adequate

control

of

the

rate

ofheating

can

be

achieved,

thus

minimizing

the

thermal

degradation

effects

on

desirable

product

attributes

but maintaining a safe product

Non‐thermal approaches to milk processing may be also valuable alternative to the thermal processing:

High Hydrostatic Pressure

Why ?

:•

Ability

to inactivate microorganisms at near‐ambient temperatures,

avoiding the undesirable effects of heat on the organoleptic properties of foods.

•

Maintenance of sensorial and nutritional properties of the products


High pressure in food processing

High Hydrostatic Pressure (HHP)

Novel non‐thermal processing technology

Hydrostatic pressure (between 100‐600 MPa) is applied to the food at room temperatures;


Advantages of the use of HHP in food processing

Applied pressure is transmitted instantaneously and homogeneously into the food, regardless of its shape and

geometry

The

minimum

processing

using

no

additives

allows

the obtention of higher nutritional and organoleptic quality foods, with a better texture and improved shelf life

High

pressure

systems

have

a

wide

application

in

other industries

– they

just

need

to

be

“transferred”

to

the

food

industry


•

Japan

was

the

first

country

where

High

Pressure

processed foods

were

produced

and

sold,

namely

jams,

fruit

yoghurts,

sauces and lemon juice

•

Nowadays, there is a wide range of HPP processed products – meat products, fruit juices & smoothies, seafood, dairy

products, RTE meals,…

•

These products are targeted as high quality and high price


Applications in dairy products

•

Yogurt•

Inactivation of yeast and moulds

•

Reduction of Lactobacillus number•

Inactivation of contamination and acidification bacteria (survival of

probiotics starins)

•

Cheese•

Enhanced maturation and elimination of pathogenic bacteria

•

Increase cheese yield

•

Milk•

Improved shelf life and improved properties of products made with HPP

processed milk


High pressure in food processing

Milk Processing

HPP

is

considered

an

interesting

alternative

for

milk

heat pasteurization and sterilization

Microoganism

and certain enzymes are inactivated:

Due to absence of heat, fresh flavor, color, taste and vitamins are minimally affected


Applications in dairy products

Control migration of O2

, CO2

, H2

O, aromas and/or lipids

Carry active compounds (antimicrobials, antioxidants)

Improve appearance

Materials used: Polysaccharides (starch, cellulose,

chitosan); Proteins (milk, soy); Lipids (waxes, oil)

Consumer demand for ready-prepared

foods Consumer Health and

Safety

Shelf-life extension

Environmental impact

Edible coatingEdible coating

Edible coatings and films

•

Wetability,

•

Water vapour permeability,

•

O2 and CO2

permeability,

•

Solubility in water,

•

Colour –

opacity and L*a*b*

•

Thermal analysis (DSC and TGA),

•

Mechanical analysis –

tensile streght, elongation-at-break and Young’s modulus (Instron).

Relevant Coating and films properties


•

Cheese with coating has a lower gas transfer rates as well as a decrease of the

relative

weight

loss

(ca.

8‐fold

less

the

value

in

the

absence

of

coating).

O2

and CO2

transfer rates in cheese at 21.86 ±

0.76 °C.

Cerqueira et al. (2009). J. Agric. Food Chem. 57, 1456–1462

Cheese Applications


•

Visual

evaluation

also

confirmed

that

the

uncoated

cheese

suffered

from an extensive mold growth when compared with the coated cheese.

Cheese with coating (a) and without coating (b).

(a) (b)

Cerqueira et al. (2009). J. Agric. Food Chem. 57, 1456–1462

Cheese Applications


Cheese Applications

•

Extend product shelf-life •

Reduce the risk of pathogen growth on food surface

Inhibition of A. niger with chitosan‐natamycin coating. Cheese uncoated (A) and coated with chitosan containing natamycin 0.125 mg∙mL‐1

(B), 0.25 mg∙mL‐1

(C) and 0.50 mg∙mL‐1

(D). 1

A B

C D

A B

C D

Fajardo et al. (2010). Journal of Food Engineering 101, 349–356.

Incorporation of antimicrobial agent


•

Potential application of nisin-coated films onto cheese in order to overcome the problems associated with post-process contamination of Listeria monocytogenes

•

The addition of nisin to galactomannan films is a viable alternative to reduced microbial growth, reduce water loss and increase ricotta cheese shelf-life.

Nisin-added coating prevented the growth of L. monocytogenes

during 21 days

0

1

2

3

4

5

6

7

8

0 2 7 14 21 28

log CFU/g

Storage time (days)

ControlCoating (no nisin‐added)Coating with nisin

Martins et al. (2010). J. Agric. Food Chem. 58, 1884–1891.

Incorporation of antimicrobial agent


Lactose intolerance is the inability to metabolize lactose, because of a lack of the required enzyme lactase in the digestive system. It is estimated that 75% of adults worldwide show some decrease in lactase activity during adulthood

Global map of lactose intolerance frequencies

Lactose free products

http://en.wikipedia.org/wiki/File:Laktoseintoleranz-1.svg

Lactose free products

Solutions for lactose intolerance

Consume lactose-free and lactose-reduced milk and milk

products

Lactose hydrolysis by the addition of lactase (-

galactosidase

Development of efficient system for lactose hydrolysis (use of

immobilized lactase)

Development of low lactose content dairy products

Probiotics are live microrganisms thought to be healthy for the host organism. According to the currently adopted definition by FAO/WHO, probiotics are: "Live microorganisms which when administered in adequate amounts confer a health benefit on the host".

Lactic acid bacteria (LAB) and bifidobacteria are the most common types of microbes used as probiotics; but certain yeasts and bacilli may

also be

helpful.

Probiotics are commonly consumed as part of fermented foods with specially added active live cultures; such as in yogurt, soy yogurt or as dietary supplements.

Probiotics are able to survive in the product and become active when entering the consumer’s gastrointestinal tract

Probiotic dairy products

Factors to be considered in the development of probiotic dairy products

the physiologic state of the probiotic

selection/identification of new probiotic strains

the physical conditions of product storage (eg, temperature)

the chemical composition of the product to which the probiotics are added (eg,

acidity, available carbohydrate content, nitrogen sources, mineral content, water

activity, and oxygen content)

development of techniques to enhance the survival of probiotic bacteria

interactions of the probiotics with the starter cultures (eg, bacteriocin

production, antagonism, and synergism)

understanding of probiotic health benefits.

Probiotic dairy products

Cheese whey valorization

Cheese whey

MILK

Casein (80%) Whey (20%)

s1-casein

s2-casein

-casein

-casein

-lactoglobulin (50%)

-lactalbumin (20%)

Bovine albumin serum (10%)

Immunoglobulins (10%)

Minor proteins (10%)

(e.g. LF, LP, PP, OPN, GMP)

Cheese whey

Whey

Growth factors

Hormones

Ultra-residual elements

Bioactive peptides

Minor proteins

Major proteinsGram/L Microgram/L

Miligram/L Nanogram/L

Residual elements

Main minerals

Milk fat

Lact

ose

Vita

min

s

Enzy

mes

Non proteic

nitrogen

Am

ino acids

Cheese whey

Cheese whey

Source –

3A Business Consulting

Cheese whey proteins - Market growth rates

Cheese whey

Whey to bioethanol…

8 million tons of lactose

(worldwide

annual

whey production)

~50% not transformed into added‐value sub‐products

~2.3 million

m3

ethanol

considering a 85% conversion yield

Worldwide production of bioethanol for fuel in 2008: ~65 million

m3

~3.5% of the 2008 world production~3.5% of the 2008 world production

Biotechnol Adv (2010) 28: 375-384

Cheese whey

Whey to Ethanol Industrial Plants

Ireland Carbery Milk ProductsCarbery Milk Products

since 1978, potable ethanol & ethanol for fuel (since 2005)11 000 tons ethanol /year

New Zealand FonterraFonterra

Anchor Ethanol (Fonterra subsidiary)potable ethanol & ethanol for fuel (since 2007)17 million liters ethanol /year

United States Golden CheeseGolden Cheese

Land OLand O’’LakesLakes

Germany MMüüllermilch llermilch

near Dresden; 10 million litres ethanol /year from dairy by-products

Cheese whey

Cheese whey

Prebiotics -

“selectively fermented ingredients that allow specific changes, both in the composition and/or activity in the gastrointestinal microbiota that confers benefits upon host well-being and health”

Classification criteria

Resistance to the upper gut tract

Fermentation by intestinal microbiota

Beneficial to the host health

Selective stimulation of probiotics

Stability to food processing treatments

Cheese wheyLactose as a source of prebiotics

Method % (p/p) rsd

Ash AOAC 31.013 0.02 4.2

Moisture AOAC 925.45 1.12 24.2

Protein Kjeldahl 0.15 6.2

Saccharides HPLC 99.5 3.6

Monosaccharides 2.2 4.9

Disaccharides 4.1 25.9

Oligosaccharides 94.0 1.7

Trisaccharides 41.8 2.5

Tetrasaccharides 41.6 1.9

Pentasaccharides 10.5 3.5

•Fermentation process –

high yields and productivity;

•Purified GOS are pure with ~99.5% of saccharides and ~94.0% of oligosaccharides;

•GOS are stable under severe gastric and duodenal conditions

•The PI score of the GOS sample is relatively high.

Cheese whey

Universidade do MINHO

Braga

Guimarães

Thank you for your attention !

9. Necesidades y oportunidad investigacion - Teixeira

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