AGRICULTURAL RESEARCH COMMUNICATION CENTRE

www.arccjournals.com / indianjournals.comAsian J. Dairy & Food Res., 32 (4) : 257-265, 2013

PROCESS OPTIMIZATION FOR THE PRODUCTION OFWHEY PROTEIN ENRICHED DAIRY DRINK

H.R. Gupta* , S.K. Kanawjia, M.K.Saluja1, H.C. Devaraja and Avneet Rajoria2

Dairy Technology DivisionNational Dairy Research Institute, Karnal-132001, India

Received: 07-02-2013 Accepted: 09-11-2013

ABSTRACTWhey protein enriched dairy drink was formulated using buffalo milk, WPC 70 (0.5-5.0%), Sugar

(6-8%), Carrageenan (0.2-1.0%) and Milk fat (1.5-4.5%) and optimized using response surfacemethodology. The final product was evaluated for physico-chemical qualities viz. fat, SNF, protein,ash, sugar and total solids and sensory qualities viz. smell, taste, consistency, color and appearanceand overall acceptability. The optimum product qualities in terms of smell (22.45), taste (22.11),consistency (25.19), color and appearance (18.49) and overall acceptability (88.24) were obtainedusing combination of WPC 70 @ 0.5 %, sugar @ 8 %, carrageenan @0.38 % and milk fat @1.5 %.

Key words: Functional drink, Milk, Sensory, Response Surface Methodology, WPC-70

* Corresponding author, email ID:hrgndri@gmail.com1 School of Agriculture, IGNOU, Delhi; 2 154, Sector 7, Urban Estate, Karnal – 132 001, India

INTRODUCTIONFunctional foods by virtue of the presence of

physiologically active components provide healthbenefits beyond basic nutrition. Interestingly,nowadays the consumer’s needs are more than justrefreshment from their drinks. Consumer’s opinionabout the drink has now turned out to be the providerof energy and to rehydrate exercised bodies andsoothen the rattled nerves. Recent introduction ofretail chains has created huge potential drinks withfunctional and therapeutic values. Whey as a by-product obtained during the production of cheese,casein, paneer, chhana, shrikhand, etc. containswhey proteins known to exhibit excellent nutritionalvalue and functional properties. Whey proteins arealso known to carry bio-protective agents possessinganti inflammatory property. Whey proteins providesolubility over wide range of pH, in addition to waterbinding capacity, whipping, emulsification andgelation properties.

MATERIALS AND METHODSRaw materials: Buffalo milk procured fromExperimental Dairy of N.D.R.I., Karnal was adjustedto 1.5, 3.0 and 4.5% fat level using skim milk. Themilk samples were pasteurized and kept underrefrigerated conditions. WPC 70 procured from

Modern Dairies Limited, Karnal was used foroptimizing functional dairy drink. WPC 70 testedmoisture 5.5%, protein 77.0%, fat 8.0%, lactose6.5% and minerals 3.0%. LDPE film (thickness 70µm) was used for the packing of formulated dairydrink. Carrageenan was procured from SigmaAldrich Co., predominately containing k-Carrageenan. Cane Sugar was purchased from localmarket and grounded to powder form before mixing.

Development of functional dairy drinkThe dairy drink was developed as per the

flow diagram given below

Buffalo milk

Preheating (40°C)

Addition of WPC (0.5%)+ Stabilizer (0.38%)+Sugar (8.0%)

Mixing

Filtration

Homogenization (175kg/cm2)

Heat treatment (80°C/15sec)

Cooling (4°C)

Packing

Storage (4°C)

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Flow diagram for the preparation of wheyprotein enriched functional dairy drink:Functional drink was developed using buffalo milk(1.4% fat) heated to 40°C for efficient filtration anddissolving ingredient viz. WPC 70, Stabilizer(carrageenan) and sugar. The ingredients were mixedthoroughly and the mix is filtered. The mix ishomogenized at 175kg/cm2 and subjected to heattreatment of 80°C for 15sec. then it is cooled to 4°C,packed and stored under refrigeration temperature.

Experimental design: The independent variablesused in this investigation were: WPC (0.5-5.0%),Sugar (6-8%), Carrageenan (0.2-1.0%) and Milk fat

(1.5-4.5%) as depicted in the Table 1. The responsesselected were smell, taste, consistency, colour andappearance and overall acceptability. Experimentswere conducted following the CCRD designemployed in Response Surface Methodology (RSM).The experiment comprised of 30 trials (Table 2). Theexperimental data were assigned to a commercialstatistical package, Design Expert – version 7.1.5(Statease Inc., USA). The goals were set forindependent variables, i.e. WPC, sugar, carrageenanand milk fat (in range) and responses i.e. smell, taste,consistency, colour and appearance and overallacceptability (maximize)(Table 3).The recommended

TABLE 1: Range of WPC, sugar, carrageenan and milk fat (4-factor CCRD).

Factor Name Units Low Actual High Actual Low coded High Coded

A WPC g 0.5 5.0 -1.00 1.00B SUGAR g 6.0 8.0 -1.00 1.00C CARRAGEENAN g 0.02 0.10 -1.00 1.00D MILK FAT g 1.5 4.5 -1.00 1.00

TABLE 2: The central composite rotatable design for four independent variables: WPC, sugar, carrageenan and milk fat.

Standard Composition, % Sensory Scores

Order WPC Sugar Carrageenan Milk Fat Overall Smell Taste Consistency Colour andacceptability appearance

1 0.50 8.00 0.10 4.50 83.25 22.25 21.88 22.00 17.122 2.75 9.00 0.06 3.00 78.99 21.43 19.14 22.57 15.853 0.50 6.00 0.10 1.50 84.68 22.00 21.60 22.33 18.754 5.00 6.00 0.02 1.50 76.00 22.45 18.63 20.65 14.275 5.00 8.00 0.10 4.50 67.20 21.00 18.00 16.95 11.256 0.50 8.00 0.02 4.50 83.62 21.33 18.66 24.83 18.807 2.75 7.00 0.06 3.00 82.88 22.00 21.38 23.25 16.258 5.00 6.00 0.10 4.50 76.79 20.75 19.60 19.64 16.809 2.75 7.00 0.06 3.00 82.97 21.25 21.10 22.80 17.8210 2.75 7.00 0.06 3.00 81.10 20.76 19.76 21.80 18.7811 2.75 5.00 0.06 3.00 80.88 21.63 21.38 20.25 17.6212 5.00 8.00 0.02 1.50 76.48 21.43 18.85 20.57 15.6313 5.00 8.00 0.02 4.50 75.73 19.75 17.85 21.85 16.2814 5.00 8.00 0.10 1.50 73.29 20.75 19.43 17.46 15.6515 0.50 8.00 0.10 1.50 87.60 22.60 22.60 23.80 18.6016 0.50 6.00 0.10 4.50 83.25 22.25 21.88 22.00 17.1217 0.50 8.00 0.02 1.50 88.37 22.50 21.88 25.87 18.1218 0.50 6.00 0.02 4.50 82.05 21.63 21.25 21.05 18.1219 2.75 7.00 0.06 0.00 82.86 21.50 21.86 23.25 16.2520 2.75 7.00 0.06 3.00 80.30 20.65 19.23 23.25 17.1721 7.25 7.00 0.06 3.00 63.45 20.68 16.85 14.96 10.9622 2.75 7.00 0.06 3.00 83.25 22.25 21.88 22.00 17.1223 2.75 7.00 -0.002* 3.00 78.62 22.83 19.56 19.73 16.5024 5.00 6.00 0.02 4.50 75.25 21.25 19.75 20.00 14.2525 2.75 7.00 0.06 3.00 82.13 21.43 21.80 23.30 15.6026 0.50 6.00 0.02 1.50 84.59 24.25 20.78 21.66 17.9027 2.75 7.00 0.14 3.00 78.40 21.83 19.83 21.58 15.1628 5.00 6.00 0.10 1.50 75.55 20.33 17.20 21.57 16.4529 2.75 7.00 0.06 6.00 78.45 20.91 19.61 21.48 16.4530 -1.75* 7.00 0.06 3.00 83.25 22.25 21.88 22.00 17.12

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Partial coefficients

Sensory characteristics

Overall acceptability Smell Taste Consistency Colour and

appearance

Intercept A-WPC (g) 248.24* 34.06* 60.91* 64.05* 38.32* B-Sugar (g) 0.70 2.30 2.26 3.48 0.96 C-Carrageenan (g) 2.03 3.65 1.61 2.09 0.54 D-Milk Fat (g) 13.58* 8.90* 2.71 3.52 0.80 A2 103.21* 0.058 5.83* 25.27* 7.67* B2 2.36 0.17 0.97 1.35 0.033 C2 11.58* 6.32* 3.56 4.66* 0.66 D2 0.35 0.20 0.050 9.244E-003 0.058 BA 9.38* 0.040 0.029 13.31* 0.60 CA 2.97 0.52 3.64 1.10 0.050 CB 5.93* 8.59* 2.15 14.43* 5.09* DA 1.15 0.71 1.71 0.25 0.064 DB 3.97 0.010 10.57* 0.13 0.53 DC 0.087 13.21* 0.93 0.80 3.30 Lack of fit 2.15 (NS) 0.40 (NS) 0.32 (NS) 2.76 (NS) 1.20 (NS) Model F value 23.74 5.64 6.79 9.41 4.18 R2 0.957 0.840 0.864 0.898 0.796 Press 181.41 12.46 31.40 75.39 96.31 Adeq. Press 21.500 10.099 10.812 13.621 8.667

TABLE 3: Regression coefficients and ANOVA of fitted quadratic model of Whey Protein enriched dairy drink.

solution of RSM study was used for the productionof whey protein enriched dairy drink (Table-4). Thesamples of various formulations were served to thepanel of 8 sensory judges. The results of the sensoryjudgment were subjected to diagnostic check in thequadratic model. Regression analysis and analysisof variance (ANOVA) was conducted for fitting themodels (Table 5) and to examine the statisticalsignificance of the model. The adequacy of themodels were determined using model analysis, lack-of fit test and R2 (coefficient of determination)analysis as outlined by Lee, J et al (2000).

Sensory analysis: A 100 point score card suggestedby ADSA (1941) was used for the sensoryevaluation. Sensory evaluation of milk was done by8 judges of the trained sensory panel. Functional drinksamples were served to judges after tempering themto 15-20oC.

Chemical analysis: Titratable acidity (% lactic acid)of whole milk and skim milk was measured bystandard method described in IS: 1479 (Part I) -1960.The pH values of milk and formulated samples weredetermined electrometrically by a calibrated pHmeter (PHAN LABINDIA Labtek Engg. Pvt. Ltd.,India) by the method described in IS: SP (Part XI,

1981). Fat content in whole milk, skim milk ,standardized milk and formulated samples weredetermined by the Gerber method described in IS:1224 (Part I)-1977. Total solid content in whole milk,standardized milk and formulated samples weremeasured by standard method described in IS:12333 -1973. The ash content of formulated sampleswas determined by gravimetric method describedin IS: 1479 (Part II) -1961. Lactose content offormulated samples was determined by subtractingfat, protein, ash content and moisture content from100. The protein content of formulated samples wasdetermined by semi-micro Kjeldahl method describedby Menefee and Overman (1940) using Kjeltecdigestion and distillation equipment (2300, KJELTECAnalyzer, FOSS) followed by manual method.

RESULTS AND DISCUSSIONEffect on overall acceptability: Among differentcombinations of WPC, sugar, carrageenan and milkfat, milk drink prepared from buffalo milk with 0.5%WPC, 8.0% cane sugar, 0.02% carrageenan and1.50% fat secured maximum overall acceptabilityscore of 88.37 out of 100 (Table 2). The Fig 1-Aclearly depicts that, the linear and quadratic effectof WPC on overall acceptability of functional drink

* Significant at 1 percent; NS – Not Significant

260 ASIAN JOURNAL OF DAIRY & FOOD RESEARCH

TABLE 4: Goal set in RSM for optimizing the whey protein enriched dairy drink.

Constituents Goal set for Formulated Lower Limit Upper Limit Dairy Drink

Factors

WPC is in range 0.5 5.0Sugar is in range 6.0 8.0Carrageenan is in range 0.02 0.10Milk fat is in range 1.5 4.5Responses

Overall acceptability maximize 63.45 88.37Smell maximize 19.75 24.25Taste maximize 16.85 22.60Consistency maximize 14.94 25.87Colour and appearance maximize 10.96 18.80

TABLE 5: Suggested solution for whey protein enriched dairy drink by RSM.

Solution Solution Formulation DesirabilityNo. WPC (g) Sugar (g) Carrageenan (g) Milk Fat (g)

1 0.50 8.00 0.38 1.50 0.8682 0.53 8.00 0.21 1.50 0.8653 0.53 8.00 0.72 1.73 0.8414 1.03 7.90 0.20 1.50 0.8385 1.22 6.73 0.42 1.50 0.788

is negatively significant (p < 0.01). Increase in thequantity of WPC resulted in decreased overallacceptability score.

Interaction effect of sugar and WPC (Fig. 1-B) and carrageenan and sugar (Fig. 1-D) found toreduce the overall acceptability score of functionaldrink significantly. Increasing milk fat content (Fig.1-C) in the product significantly increased the overallacceptability score (p < 0.01).

The regression equation describing the effectof the process variables on overall acceptability scoreof functional dairy drink in terms of actual level ofthe variables are given as:

Overall acceptability = + 42.255 + 3.673 * WPC70 + 8.292 * SUGAR + 230.383 *CARRAGEENAN + 2.925 * MILK FAT- 0.532* WPC 70 * SUGAR - 7.486 * WPC 70 *CARRAGEENAN + 0.124 * WPC 70 * MILK FAT-23.812 * SUGAR * CARRAGEENAN - 0.519 *SUGAR * MILK FAT-1.916 * CARRAGEENAN* MILK FAT- 0.383 * WPC 702 - 0.293 * SUGAR2 -406.119 * CARRAGEENAN2 - 0.050 * MILKFAT2

Effect on flavour: Interaction effect of sugar andcarrageenan was found to be significant (P< 0.01).Increasing sugar along with carrageenan from 6%to 8% and from 0.02% to 0.1% respectively,

increased the flavour score of whey protein enricheddairy drink (Fig.2-A). WPC and milk fat were foundto have significant (P< 0.01) effect on flavour scoreof whey protein enriched dairy drink at linear effect(Fig 2-B). However, there was no significant effectof their interaction. The quadratic effect ofcarrageenan and interaction effect of carrageenanwith milk fat were found to be significant (P< 0.01)on flavour score of functional drink (Fig 2-C).Increasing carrageenan decreased the flavour scoresignificantly. Increasing carrageenan levels alongwith milk fat increased the flavour score of wheyprotein enriched dairy drink.

The regression equation describing the effectof the process variables on flavour score of functionaldairy drink in terms of actual level of the variablesare given as:Flavour = + 31.658-0.244 * WPC 70-1.244 *SUGAR-106.541 * CARRAGEENAN-0.686 *MILK FAT-0.011 * WPC 70 * SUGAR-1.00 *WPC 70 * CARRAGEENAN + 0.031 * WPC 70 *MILK FAT + 9.125 * SUGAR * CARRAGEENAN+8.333 E-003 * SUGAR * MILK FAT + 7.541 *CARRAGEENAN * MILK FAT+ 4.52675E-003 *WPC 702 + 0.039 * SUGAR2 + 149.479 *CARRAGEENAN2- 0.018 * MILK FAT2

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TABLE 6: Verification of the predicted and observed sensory scores of whey protein enriched dairy drink.

Sensory Attributes Functional Dairy Drink

Predicted Values a Observed Values b t 0.05 Value

Overall acceptability 88.24± 0.70 88.38± 0.8 0.09ns

Smell 22.45± 1.0 23.05± 1.0 0.39ns

Taste 22.11± 1.2 22.68± 0.8 0.47ns

Consistency 25.19± 1.5 24.56± 1.8 0.41ns

Colour and appearance 18.49± 0.7 19.02± 0.5 0.31ns

a Predicted values of Design Expert 6.0.10 packageb Actual values (average of 3 trials) of optimized productns – Non significant (P< 0.05)

FIG. 1A FIG. 1B

FIG. 1C FIG. 1DFIG. 1: Effect of various combination of WPC, sugar, carrageenan and milk fat on overall acceptability of milk drink

The Model F-value of 5.64 in the Table 3 impliesthat the model is significant. The “Lack of Fit F-value” of 0.40 implies the Lack of Fit is not significantrelative to the pure error.

Effect on taste: From the Table 3, it is very clearthat taste of functional drink depended mainly on

and 0.06% respectively, decreased the taste scoreof whey protein enriched dairy drink (Fig 3-B).

The regression equation describing the effectof the process variables on flavour score of functionaldairy drink in terms of actual level of the variablesare given as:

262 ASIAN JOURNAL OF DAIRY & FOOD RESEARCH

Fig. 2A Fig. 2B

Fig. 2C FIG. 2: Effect of various combination of WPC, sugar, carrageenan and milk fat on flavour of functional drink

The Model F-value of 6.79 implies that themodel is significant. The “Lack of Fit F-value” of0.32 implies the Lack of Fit is not significant relativeto the pure error.

Effect on consistency: WPC has been found toaffect the consistency of the functional drinksignificantly both at its linear and quadratic levels(Table 3). Increasing WPC in the functional drinkreduced the consistency scores. It is evident fromFig. 4-A, that increasing sugar content increased theconsistency of the product. However, its interactioneffect with WPC was found to get decreased

significantly. On the other hand, increase incarrageenan concentration increased theconsistency score (Fig 4-B) and interaction of milkfat and sugar also increased the consistency scoreof the product (Fig 4-C) but the increase wasstatistically insignificant.

The regression equation describing the effect ofthe process variables on constancy score of wheyprotein enriched dairy drink in terms of actual levelof the variables are given as:

Consistency = - 7.031+ 3.196 * WPC 70+ 5.805* SUGAR + 207.476* CARRAGEENAN-

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0.603* MILK FAT-0.402 * WPC 70 * SUGAR -2.895* WPC 70 * CARRAGEENAN+ 0.036 * WPC70 * MILK FAT-23.578 * SUGAR *CARRAGEENAN + 0.060 * SUGAR * MILK FAT-3.697* CARRAGEENAN * MILK FAT-0.188 * WPC702-0.220 * SUGAR2 - 255.794 * CARRAGEENAN2

+ 8.10185E-003 * MILK FAT2

The Model F-value of 9.41 implies that the model issignificant. The “Lack of Fit F-value” of 2.76 impliesthe Lack of Fit is not significant relative to the pureerror.

Effect on colour and appearance: Fig 5-A depictsthat color and appearance of the drink is mainlydependent on WPC content. Table 3 shows that linearand quadratic effect of WPC was found to besignificant (0.01%). Increasing levels of WPCdecreased the score of color and appearance butincreasing carrageenan and sugar levels increasedcolor and appearance score individually. Theirinteraction effect was found to decrease the scoresignificantly (Fig 5-B).

The regression equation describing the effect of theprocess variables on color and appearance score ofwhey protein enriched dairy drink in terms of actuallevel of the variables are given as:

Colour and appearance = + 8.00613+ 0.759 *WPC 70 + 0.910 * SUGAR + 152.506 *CARRAGEENAN + 1.617 * MILK FAT- 0.103* WPC70 * SUGAR + 0.743*WPC 70 * CARRAGEENAN- 0.022 * WPC 70 * MILK FAT-16.859* SUGAR *CARRAGEENAN -0.144* SUGAR * MILK FAT -9.052 * CARRAGEENAN * MILK FAT - 0.124 *

WPC 702+ 0.041* SUGAR2 -115.559 *CARRAGEENAN2-0.0243 * MILK FAT2

The Model F-value of 4.18 implies that the modelis significant. The “Lack of Fit F-value” of 1.20implies that the Lack of Fit is not significant relativeto the pure error.

Optimization of formulation of whey proteinenriched dairy drink: The desired goals for eachvariable and response were chosen and differentweightages were assigned to each goal as depictedin Table 4 to adjust the shape of its particulardesirability function. Table 5 shows softwaregenerated five solutions with optimum levels ofindependent variables. Solution No.1, having themaximum desirability value was selected as theoptimum formulation for the production of functionaldairy drink.

The sensory evaluation of optimum solutionwas conducted. The observed values of sensoryscores (mean of 3 measurements) as well as thepredicted scores are presented in Table 6, in whichboth the values were found to be similar andstatistically (two sample t-test) analysed to be nonsignificant. The selected formulation was used forthe production of whey protein enriched dairy drink.

CONCLUSIONRSM was successfully used to determine the

optimum combination of WPC-70, milk fat,carrageenan and sugar level for whey proteinenriched dairy drink. The modeling of experimentaldata allowed the generation of useful equations forgeneral use in predicting the behavior of the system

Fig. 3B Fig. 3A FIG. 3: Effect of various combination of WPC, sugar, carrageenan and milk fat on taste of whey protein enriched dairy drink

264 ASIAN JOURNAL OF DAIRY & FOOD RESEARCH

Fig. 4A Fig. 4B

Fig. 4C FIG 4: Effect of combination of WPC, sugar, carrageenan and milk fat on taste of whey protein enriched dairy drink

Fig. 5B Fig. 5A FIG. 5: Effect of various combination of WPC, sugar, carrageenan and milk fat on colour and appearance of whey protein

enriched dairy drink.

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TABLE 6: Verification of the predicted and observed sensory scores of whey protein enriched dairy drink.

Sensory Attributes Functional Dairy Drink

Predicted Values a Observed Values b t 0.05 Value

Overall acceptability 88.24± 0.70 88.38± 0.8 0.09ns

Smell 22.45± 1.0 23.05± 1.0 0.39ns

Taste 22.11± 1.2 22.68± 0.8 0.47ns

Consistency 25.19± 1.5 24.56± 1.8 0.41ns

Colour and appearance 18.49± 0.7 19.02± 0.5 0.31ns

a Predicted values of Design Expert 6.0.10 packageb Actual values (average of 3 trials) of optimized productns – Non significant (P< 0.05)

under different factor combinations. The proteinenriched functional dairy drink produced by theoptimized process was found to contain 1.40%fat, 8.8%SNF, 3.58% protein, 0.61% ash, 8%sugar and 17.85% TS . The average overall

acceptability score of final beverage was 8.8. Thecurrent study resulted in the development of adairy drink with increased whey protein contentfor enhanced health attributes and sensoryquality.

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Bhawan, New Delhi.BIS (1961): Method of test for dairy industry: Part 2 Chemical analysis of milk IS 1479 : Part 2 Bureau of Indian

Standards, Govt. of India 1961.BIS (1960): Methods of test for dairy industry: Part 1 Rapid examination of milk (IS 1479 : Part 1) Bureau of Indian

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