new and emerging technologies for whey processing: “is there a better whey?” alan l. kelly...
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New and emerging technologies for whey
processing:“Is there a better whey?”Alan L. Kelly
Seamus A. O’Mahony
School of Food and Nutritional SciencesUniversity College Cork, Ireland
Why New Approaches to Whey Processing?
• Range of technologies well established for whey processing (centrifugal/membrane separation, ion exchange, spray-drying, heat treatment)
• Increasing awareness of sensitivity of whey components (i.e., protein) to process variables (e.g., temperature, pH)
• Demand for more discriminating and efficient approaches to whey fractionation and treatment
• Novel ways of producing wheyhow do we produce whey with different composition/ functionality?
• Novel ways of processing wheyhow could we process whey to achieve different goals?
Whey processing overview
MilkSeparation/fractionation
WheyCasein/curd
Pre-processing to stabilise
Raw milk
Pretreatment?
Fractionated Whey Products
Whole whey
products
Functional Food
Ingredients
FractionationDrying etc.
The production of whey
MilkSeparation/fractionation
WheyCasein/curd
Raw milk
Pretreatment?
• Developments in pre-treatment of milk for cheese-making or casein manufacture
• More and more whey from non-cheese sources• Possible new approaches include casein
precipitation by thermodynamic approaches• Developments in production of ideal or
native whey without complications of rennet, starter, acid addition
The Production of Ideal Whey?
• Ideal Whey/Native Whey/Virgin Whey/Milk Serum Protein
• Whey stream extracted directly from milk using microfiltration membranes
• Further processed as per all other whey streams to produce WPC, WPI etc.
Advantages of Ideal Whey (compared with regular whey):
1.Clean flavour and aroma2.Low turbidity and good clarity3.Increased levels of native whey proteins (at least at point of preparation)
4.Improved protein profile and quality (e.g., GMP, NPN)
The production of ideal whey
Milk
Microfiltration
WheyCasein retenta
te
Phosphocasein, Cheese etc
WPI, WPC etc
Cheese Whey
Ideal Whey
Starter Culture Yes No
Rennet Yes No
Glycomacropeptide Yes No
Colour Yes No
Fat/Phospholipids Yes Negligible
Pasteurisation Steps 2 1
pH <6.5 >6.6Potential use for colour-free whey production
Colour removal from whey: a significant challenge
Zhang et al (2013)Journal of Agricultural and Food
Chemistry, 61, 9230-9240
• Choice of approaches between avoidance and removal
• End-user preference is key
• Absorption methods developed
• Bleaching possible by a number of chemical and enzymatic means
• Precipitation by physico-chemical means developed
• Also could combine alternative colourant usage with encapsulation
Developments in whey stabilisation
Milk
WheyCasein/curd
Pre-processing to stabilise
Raw milk
• Cheese whey a very unstable and dynamic material
• Curd and fat to be removed
• Coagulant and other (milk enzymes) active
• Starter present and active
• Heat treatment/separation typically used to stabilise
The potential of new technologies for
whey
Why might these help?
• Whole family of (generally) non-thermal technologies currently of interest as alternatives to heat treatment
• Some broken through (e.g., high-pressure) to industry; others at lab scale
• Cost, scale and maturity challenges in many cases
• Potential for retention of techno-functional or bio-functional properties of whey products while inactivating undesirable micro-organisms or other agents
• Greater discrimination than heat between sensitivities of different species/molecules
• Less effect on small molecules than heat
Technology Effects on milk Possible whey
applications
High-pressure
treatment
Microbial and enzymatic
inactivation; changes in
protein functionality
High-pressure
homogenisation
Emulsification; microbial
inactivation; enzyme
inactivation
Pulsed electric
field treatment
Microbial inactivation;
changes in micelle size and
rennet coagulation
Ultrasound Inactivation of bacteria and
enzymes
High-intensity light
pulses
Microbial inactivation
New technologies with possible applications for
whey
Differential
protein
denaturation;
preservation of
biological
activities;
microbial
decontamination
without protein
denaturation
Reduced light-scattering
High-Pressure Treatment and Milk Properties
• Increasingly commercially viable process• Dramatic and often unique impacts on milk proteins (caseins and whey proteins)
• Impact on casein micelles of potential interest for cheese milk treatment/protein functionality manipulation
High pressure and
whey proteins
40
60
80
100
120
140
0 200 400 600 800Pressure (MPa)
Rel
ativ
e ch
ange
(%
)
Curd yield
% Moisture in curd
% Nitrogen in whey
Denatured -la
Complexed -lg
Denatured -lg
• HPP denatures WP and incorporates into curd
• Altered protein profile in whey
Differences in denaturation of whey
proteins if HP-treated in milk or whey
• Difference in denaturation of -lg if HP-treat milk or whey
• Potential to tailor whey protein profile for functionality
Huppertz et al (2004)Journal of Dairy Research, 71, 481-495
High pressure and whey
bioactives?• Increasing interest in recovery of biologically-functional proteins from whey
• How to achieve microbial stability without loss of such functionality?
• Potential for use of HPP at tailored conditions of pH
• Studies of LF stability in whey under pressure
Franco et al (2013)J. Dairy Res., 80,
128-290
Buffer
MilkWhey400 MPa
500 MPa
600 MPa
Immunoreactive lactoferrin
Microbial control in whey by new technologiesPulsed electric field
treatment of whey combined with nisin usage, in different order of application, for inactivation of Listeria innocua
Gallo et al (2007) J. Food Eng. 79, 188-193
Pulsed electric field treatment of whey shown to protect whey proteins/lactoperoxidase
De Luiz et al (2009) Milchwissenschaft 62, 422-426
Inactivation/removal of lactic acid bacteria and bacteriophage by non-thermal methods (e.g., membranes, UV light)
Atamer et al (2014) Frontiers in Microbiology (in press)
Developments in whey fractionation
Milk
WheyCasein/curd
Raw milk
Fractionated whey products
Fractionation
Continuous development in membrane materials, operation and application
Developments in the use of membrane filtration
Ultrafiltration Use of charged membranes for tailored WPC manufactureMPC manufacture possibilities?
Microfiltration Sterile filtration (e.g., lactoferrin) or enrichment of oligosaccharides
Nano-filtration Integrated whey demineralisation processes (combined concentration and partial demineralisation)
Reverse Osmosis
Pre-concentration of liquid whey ‘Polishers’ for recovery of water from permeate and evaporator condensate
Arunkumar and Etzel (2013)Sep. Purif. Technol., 105,
121-128
Whey protein fractionation using positively-charged UF membranes
Exploiting differences in isoelectric point of whey proteins to enhance rejection at membrane surfaces
Summary and conclusions
1. Whey processing an ongoing area of technological development
2. Increasing uses of whey and its fractions create challenges which require novel solutions
3. New technologies may offer new levels of discrimination between effects
4. Future targets for whey purification??5. Likely to be significant increase in
complexity of processes and products by 8th IWC.
Many Thanks!
And… An
Invitation to visit Cork!