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!