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University of Minho Institute for Biotechnology and Bioengineering Centre for Biological Engineering Dairy workshop Lugo, 26 October 2010 J. A. Teixeira [email protected] Braga Guimarães Universidade do MINHO Overview Sustainable and clean processes Healthier foods Extended shelf‐life of milk and milk products
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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 Hydrostatic Pressure
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;
High Hydrostatic Pressure
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
High Hydrostatic Pressure
•
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
High Hydrostatic Pressure
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 Hydrostatic Pressure
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
High Hydrostatic Pressure
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
Edible coatings and films
•
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
Edible coatings and films
•
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
Edible coatings and films
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
Edible coatings and films
•
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
Edible coatings and films
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
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
Cheese whey
Source –
3A Business Consulting
Cheese whey proteins - Market growth rates
Cheese whey
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 !