The Production of Ideal Whey
Transcription
The Production of Ideal Whey
Technologies for whey processing: “Is there a better whey?” Alan L. Kelly Seamus A. O’Mahony School of Food and Nutritional Sciences University College Cork, Ireland Sources and Types of Whey Milk Casein Whey Acid casein Acidification Acid whey Rennet casein Enzymatic coagulation Rennet whey Cheese Enzymatic/Acidification Cheese whey Phosphocasein Microfiltration Ideal whey/Native Whey Sweet Whey = Cheese Whey + Rennet Whey Acid Whey = Whey from acid casein manufacture Sources and Types of Whey Whey: Overview of Processing Options Whey Powder Whey Protein Concentrate (WPC) Whey Protein Isolate (WPI) Demineralised Whey (Demin) Pre-Treatment of Liquid Whey 1. Pasteurisation (rennet enzyme and culture inactivation) 2. Separation (to remove fat – whey cream) 3. Clarification (to recover and remove casein or cheese fines) Whey Storage Rotating Screen Centrifugal Separator Pasteurisation These steps are common in the production of whey powder, WPC & WPI Why New Approaches to Whey Processing? • • • • • Range of technologies well established for whey processing (centrifugal/membrane separation, ion exchange, heat treatment, spray-drying,) 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 whey how do we produce whey with different composition/ functionality? Novel ways of processing whey how could we process whey to achieve different goals? Whey processing overview Raw milk Pretreatment? Milk Separation/fractionation Casein/ curd Whey Pre-processing to stabilise Drying etc. Whole whey products Fractionation Fractionated Whey Products Functional Food Ingredients The production of whey Raw milk Pretreatment? Milk Separation/fractionation Casein/ curd • • • • Whey 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 incompatibility 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 other whey streams to produce WPC, WPI etc. Advantages of Ideal Whey (compared with regular whey): 1. Clean flavour and aroma 2. Low turbidity and good clarity 3. Increased levels of native whey proteins (at least at point of preparation) 4. Improved protein profile and quality (e.g., GMP, NPN) The advantages of ideal whey Milk Microfiltration Casein retentate Whey Phosphocasein, WPI, Cheese etc WPC etc Cheese Whey Ideal Whey Starter Culture Yes No Rennet Yes No Glycomacropeptide Yes No Colour Yes No Fat/Phospholipids Yes Negligible 2 1 <6.5 >6.6 Pasteurisation Steps Potential use for colourfree whey production pH Cheese colour in whey: a significant challenge • • • • • • • Choice of approaches between avoidance and removal End-user preference and regulatory requirements are key Bleaching established and possible in some countries Absorption methods developed Precipitation by physico-chemical means developed Alternative colourant usage with encapsulation developed Challenge of applying avoidance principle remains Zhang et al (2013) Journal of Agricultural and Food Chemistry, 61, 9230-9240 Developments in whey stabilisation Raw milk Milk Casein/ curd Whey Pre-processing to stabilise • 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 • 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 Why might these help? • Potential for retention of techno-functional or biofunctional 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 New technologies with possible applications for whey Technology High-pressure treatment Effects on milk Possible whey applications Microbial and enzymatic inactivation; changes in protein functionality Differential protein High-pressure Emulsification; microbial denaturation; homogenisation inactivation; enzyme inactivation preservation of biological activities; Pulsed electric field Microbial inactivation; changes treatment in micelle size and rennet coagulation Ultrasound Inactivation of bacteria and enzymes High-intensity light pulses Microbial inactivation microbial decontamination without protein denaturation High-Pressure Treatment and Milk Properties . 140 Casein micelle size • 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 120 Reduced lightscattering 100 80 60 40 20 0 0 200 400 600 Pressure (MPa) 800 High pressure and whey proteins Denatured b-lg Complexed b-lg Denatured a-la Relative change (%) • HPP denatures WP and incorporates into curd • Altered protein profile in whey 140 120 100 80 % Moisture in curd Curd yield % Nitrogen in whey 60 40 0 200 400 600 Pressure (MPa) 800 Differences in denaturation of whey proteins if HP-treated in milk or whey • Difference in denaturation of b-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 • 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 Immunoreactive lactoferrin High pressure and whey bioactives? Buffe Whey Milk r 400 MPa 500 MPa 600 MPa Franco et al (2013) J. Dairy Res., 80, 128-290 Microbial control in whey by new technologies Gallo et al (2007) J. Food Eng. 79, 188Pulsed electric field treatment of whey combined with nisin usage, in 193 different order of application, for inactivation of Listeria innocua Pulsed electric field treatment of whey shown to protect whey proteins/lactoperoxidase De Luis et al (2009) Milchwissenschaft 62, 422-426 Atamer et al (2014) Frontiers in Inactivation/removal of lactic acid bacteria and bacteriophage by non- Microbiology (in press) thermal methods (e.g., membranes, UV light) Developments in whey fractionation Raw milk Continuous development in membrane materials, operation and application Milk Casein/ curd Whey Fractionation Fractionated whey products Developments in the use of membrane filtration Ultrafiltration Use of charged membranes for tailored WPC manufacture MPC manufacture possibilities? Microfiltration Sterile filtration (e.g., lactoferrin) Ideal whey production Nano-filtration Integrated whey demineralisation processes Pre-concentration (low temperature) Reverse Osmosis Pre-concentration of liquid whey ‘Polishers’ for recovery of water from permeate and evaporator condensate Whey protein fractionation using positively-charged UF membranes Exploiting differences in isoelectric point of whey proteins to enhance rejection at membrane surfaces Arunkumar and Etzel (2013) Sep. Purif. Technol., 105, 121-128 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?