Using Membrane Filtration Techniques to Fractionate Greek Yogurt Acid Whey into Value Added Ingredients

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1 Using Membrane Filtration Techniques to Fractionate Greek Yogurt Acid Whey into Value Added Ingredients B. Chen 1, K. E. Smith 2, J. A. Lucey 1,2, R. Kalscheuer 2, and M. Molitor 2 1 University of Wisconsin Madison, 2 Wisconsin Center for Dairy Research

2 Greek Yogurt Acid Whey! Byproduct of Greek Yogurt manufacture! Compared to traditional cheese whey! Lacks whey protein! High in lactic acid and calcium! Lots of lactose to be harvested! Typical current practices! Land spread! Animal feed! Biodigestor! How to add value by fractionation?

3 Whey Composition Greek Yogurt Whey Cottage Cheese Acid Whey Traditional Cheese Whey % as is basis Lactose Galactose N/A Total protein* Fat Minerals Total solids ph * Based on nitrogen content (Kjeldahl Method) so includes NPN Source: (2013, November) Greek Whey Roundtable. U.S. Dairy Export Council and Dairy Research Institute, Rosemont, IL.

4 Project Goals! Develop an economically feasible process for realizing value for acid whey from Greek yogurt manufacture! Evaluate novel nanofiltration (NF) membranes for fractionating Greek yogurt acid whey into value added streams enriched in:! Lactose! Lactic acid! Dairy minerals! Peptides! Oligosaccharides! Potential end product: lactose enriched concentrate hydrolyzed as a dairy-based sweetener

5 Ideal process flow diagram

6 Ultrafiltration! Initial step is basic WPC separation process! Retentate! Evaluate at a later date! Very low in protein (7% - 25% db)! Permeate! Focus of project

7 Ultrafiltration! 1,000 L of commercial Greek yogurt acid whey! 10,000 dalton UF membrane to fractionate the protein and fat

8 Composition of Greek yogurt feed and UF Permeate Crude GY Whey GY UF Permeate % as is basis* Lactose Galactose Lactic Acid Calcium Ash Total Protein** Total Solids ph * Results are average of 5 trials ** Based on nitrogen content and includes NPN

9 Nanofiltration! Membrane processing by experimental nanofiltration (NF) to create enriched fractions

10 CDR Why Nanofiltration?

11 NF Membranes! Use modified leakier NF membranes! Four experimental NF membranes! 3.8 in (97 mm) diameter, 38 in (965 mm) length, 75 ft 2 (7.0 m 2 ) membrane area! Commercially modified! Galactose and lactic acid pass through freely! Allow some permeation of divalents (calcium)! High degree of lactose retention

12 Nanofiltration Model Marker Percent Rejection* Control Exp 1 Exp 2 Exp 3 MgSO 4 (as divalent ions) 99.5 NaCl (as monovalent ions) 40.0 MgSO NaCl 10.0 MgSO 4 N/A NaCl N/A MgSO 4 N/A NaCl N/A *Data from Ultura Membranes

13 Nanofiltration! Test different processing conditions to achieve desired separation! Concentration: 1x, 2x, and up to 6x (~25% total solids)! Processing pressures! 200 psi! 400 psi! 600 psi! Temperatures! 40 F (4 C)! 70 F (21 C)! 110 F (43 C)! 130 F (54 C)

14 Nanofiltration Ideal NF separation Lactose Lactic Galactose Ca Acid 2+

15 Flux during NF psi psi Flux (L/min) Control Exp 1 Exp 2 Exp 3 Flux (L/min) Control Exp 1 Exp 2 Exp Temperature (F) Temperature (F) psi Flux (L/min) Temperature (F) Control Exp 1 Exp 2 Exp 3

16 Total Solids during NF 200psi 400psi % wb Control Exp 1 Exp 2 % wb Control Exp 1 Exp Exp Exp Temperature (F) Temperature (F) psi % wb Temperature (F) Control Exp 1 Exp 2 Exp 3

17 Transmission and Ratios! Compositional Measurement:! Lactose and calcium! Calculations: Concentration in Permeate Transmission = 100% ( ) Concentration in Feed Maximum ratio of Calcium transmission to Lactose transmission as desired

18 Transmission of Components Temp (F) Press ure (psi) Membrane Flux (L/min) Total Solids wb % Lactose % Calcium % Ctrl EX1 EX2 EX3 Ctrl EX1 EX2 EX3 Ctrl EX1 EX2 EX3 Ctrl EX1 EX2 EX

19 Calcium to Lactose Ratio in Transmission 8 200psi 8 400psi Ca/La Transmission Ratio NF6 Exp 1 TNF2 Exp 2 SNF20 Exp 3 Ca/La Transmission Ratio NF6 Exp 1 TNF2 Exp 2 SNF20 Exp Temperature (F) 8 600psi Temperature (F) Ca/La Transmission Ratio NF6 Exp 1 TNF2 Exp 2 SNF20 Exp Temperature (F)

20 Lactose Hydrolysis! Hydrolysis! Commercially available lactase Lactose Lactase Galactose + Glucose! Optimum ph very close to GY acid whey! Increases sweetness and reduces crystallization of lactose! Hydrolyzed dairy sweetener with clean taste and that can be put back into cultured product

21 3.0 Unconcentrated GY Permeate Hydrolysis Results Concentration % wb Galactose Glucose Time (h) Lactose * In Trial 2, the concentration of lactose was only 0.022% after 24h

22 As We Continue! Evaluate most promising membrane at higher permeate concentrations (2x, 3x, etc)! Mass balance of process! Evaluate final lactose hydrolyzed product for food applications! With a focus on use as a concentrated, hydrolyzed, partially demineralized dairy sweetener

23 ! Dairy Research Institute! Wisconsin Center for Dairy Research! Ultura Membranes (formerly Sepro)! Schreiber Foods! Lucey Lab members