ABSTRACT Processed meat loaves were prepared with dry whey, and ultrafil- trated whey protein concentrates containing 18.7% (WPC-1520) and 32.5% (WPC-3035) protein ,along with a control containing nonfat dry milk (NDM). Binding .strength; as measured by Instron shear, and tenderness, as evaluated by a taste panel, of the’NDM and three whey treatments were not different. A taste panel, using the triangle test, could not differentiate the NDM and WPC-1520 (P > 0.05), but did differentiate all other comparisons (P < 0.05). Higher sen- sory panel ratings for flavor were .given to samples containing dry whey (P’< 0.05), possibly because of flavor enhancement resulting from the high level of ‘lactose contributed by dry whey. Similarly more desirable juiciness ratings by the panel given to samples con- taining WPC-3035 (P < 0.05) may possibly be attributed to the water-binding characteristics of the high levels of whey protein.

INTRODUCTION CONSIDERABLE EFFORT is being made to increase the utilization of cheese whey through processing into different kinds of whey -protein concentrate (WPC) suitable for food enrichment and other formulated food applications (De- mott et al., 1977).

Whey proteins are an excellent source of essential amino acids, .particularly lysine (Orr and Watt, 1968; Holsinger et al., 1971). The high lysine content may be of benefit in replacing the lysine lost during the cooking procedure in meat loaf processing. The superior nutritional quality of whey protein has been further confirmed by animal feeding studies in which protein efficiency ratios of 3.0-3.2 were obtained.

Protein products obtained from cereals, oilseeds, and other plant sources that offer sensory and ‘physical charac- teristics similar to those found in meat have been approved by the USDA for use in the school lunch programs as a partial meat replacement (Rosenfield, 1973). An important aspect of the’ development of processes for new protein concentrates involves the. determination of their functional properties and an assessment of their value in various food systems.

‘The objective of this study was to assess the influence of whey protein concentrates in processed meat loaf upon the physical and sensory properties of the family loaf. _

EXPERIMENTAL Ingredients and formu!ation

“Three replicates of processed meat loaf (family loaf) were made according to the formula in Table 1. Dry whey, an ultrafiltration WPC containing 18.7% protein (WPC-1520) or an ultrafiltration WPC containing 32.5% protein (W’PC-3035) replaced the nonfat dry milk (NDM) in the treatment batches. (WPC-1520 and WPC-3035

Authors Cannon and Huffman are with the Dept. of Animal & Dairy Scknce, Auburn Univ., Auburn, AL 36830. Author Lee, formerly with Auburn Univ., is now with Lauderdale Farms, Consolidated Foods, P.O. Box 280, Norence, AL 35630.

0022-1147/80/0005-1278$02.25/O 01980 Institute of Food Technologists

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12j’(?-JOURNAL OF FOOD SCIENCE-Volume 45 (1980)

WHEY l?ROTEIN C$lNCENTRATES IN A PROCESSED MEAT LOAF

ALLEN LEE, R. Y. CANNON, and 0. L. HUFFMAN

were from Food Ingredients Division, Stauffer Chemical Company, Washington, Pa.). PY Preparation of family loaves

The ingredients were weighed. Beef was ground through a 0.32 cm plate and the pork through a 0.48 cm plate. The beef, ice water, spices; sodium nitrite, and other additives, were chopped in a silent cutter (Alexanderwerk Model SSM40S with a 6-knife head) for 1 min ‘at slow speed (10 bowl revolutions per mm). Nonfat dry milk or whey product was added and chopped for 2 min.at high speed (20”bowl revolutions ‘per mm), then the pork trimmings were added and chopped for an additional 2 mm at high speed. The mixture was stuffed into aluminum pans (20.0 cm x 9.9 cm x 6.4 cm), stored in a cooler ,overnight, then cooked in a gas oven until the interior tem- perature was 67-68°C. The temperature in the oven was kept at 88 f 1°C. After cooking, family loaves were stored in the cooler (2°C) for subsequent evaluation the following day. Cheniical analysis

Representative samples of meat loaves were ground and stored in glass jars. A random sample was collected from each jar for chemical analyses. Triplicate determinations of moisture, fat, and’ protein were made’by standard methods (AOAC, 1960). Measurement of shear force

Shear force measurements were made with an Instron, Model 1122, on seven 3.4 cm x 7.4 cm x 0.7 cm slice’s of each loaf cut immediately before the test. The Instron was equipped with an Allo Kramer shear cell and set. at a full shear force of 2 kg. Both the crosshead speed and the paper speed were set‘at 100 cm/min. Sensory evaluatjon

A sensory panel composed of 12 people was selected from em- ployees of the Dept. of Animal & Dairy Sciences, Auburn Univ. Before the evaluation, panelists participated in a’4-wk training pe- riod designed to: (1) familiarize them with test procedures, (2) im- prove their ability to recognize and identify sensory attributes, and (3) improve their sensitivity and memory permitting precise and consistent sensory judgments. The panelists were’ instructed on the sensory techniques to be used and on the methods, scales, score sheets, and terminology to be useh in the tests.

For sensory evaldation;meat loaves were cut into uniform bite sized (2.5 cm x 2:s cm x 1 cm) pieces, 10 min before each test. The product was served cold. .

All judging was carried out in individual booths under low in- tensity red light to mask ‘color differences in samples. Differences between pairs of samples were determined by the triangle test (AMSA, 1978). Tenderness, juiciness, and flavor were evaluated on an 8-point scale (l-extremely undesirable, 8-extremely desirable).

Table I-Family loaf formulationa

Amount Ingredients (cl)

tieef trimmings’(90% lean) 2841 Pork irimmings 2841 Ice water 1705 Nonfat dry milk (NDM)b 909 Salt 156 Corn syrup 57 Chopped onions (fresh) 5 White pepper 14 Sage 7 Celery (fresh) 4 Sodium nitrite 0.45

a Foimulation.from Kramlich et al. (1973). Cheptei 9, 6. 209. b Dry whey, WPC-152’0, or WPC-3035 replaced dry skim milk in the

test batches. I ‘.

WHEY PROTEIN IN PROCESSED MEAT LOAF. . .

Table 2-Averaoe moisture, fat. and protein content of family loaf

Treatment

Nonfat dry milk Dry whey WPC-1520 WPC-3035

No. of observa-

tions Moisture Fat Protein ---------------- o,. ---------------

9 66.6a ll.Oa 17.5a 9 67.3a 11.8a 14.9b 9 67.9a 11.4a 15.3b 9 67.6a 12.la 16.7a

a,b Values within columns followed by the same letters are not dif- ferent (P < 0.05) (Duncan, 1955).

Table 3-Influence of nonmeat binders on shear strength of family loaf

Treatment No. of

observations

I nstron shear value

(kg)

Nonfat dry milk 21 1 .ia Dry whey 21 1.2a WPC-1520 ?I l.ia WPC-3035 21 l.la

a Values within columns followed by the same letters are not differ- ent (P > 0105) (Duncan, 1955).

Table 4-Triangle difference tests of family loaves

NDM vs dry whey

No. Judgements corkt Probability

65. 33 0.001 NDM vs WPC-1520 66 25 0.218 NDM vs WPC-3035 66 35 0.001 Dry whey vs WPC-1520 66 39 0.0001 Dri/ whey vs WPC-3035 66 38 0.0001 WPC-1520 vs WPC-3035 65 32 0.003

RESULTS FqMILY LOAVES made with NDM, dry whey or the whey protein concentrates did not differ in moisture or fat con- tent (P > 0.05) (Table 2). However, the loaves containing NDM and WPC-3035 had slightly higher protein contents than the other samples (Table 2) due to the amount of protein contained in the raw material, The protein contents of NDM, dry whey, WPC-‘1520 and WPC-3035 are approxi- mately 36% 13% (Campbell’ and Marshall, 1978), 17.$%, and 32.5% (Manufacturer’s analyses), respectjvely. Binding strength

‘The adhesion of pieces of meat to each other is initiated by the mechanical formation of protein exudate, followed by protein coagulation during thermal processing (Gillett et al., 1978). The purpose of this experiment was to deter- mine the relative binding strength of ‘whey protein concen- trates and to determine the relationship between Instron scores and panel test scores of tenderness. The mean values of Instron shear force determinations (Table 3) among the treatments were not different (P > 0.05). Sensory evaluation

The major objective of the triangle test was to determine if panelists could differentiate between family loaves pre- pared by any two treatments. Panelists could not differenti- ate between the NDM and WPC-1.520, but did find differ- ences in the remainder of the comparisons (Table 4).

‘Mean acceptance sensory panel ratings are shown in Ta- ble 5. Juiciness and flavor were the major factors involved in determining differences among the family loaves, since there were no differences in tenderness ratings.

Table &Mean scores of tenderness, juiciness, and flavor as deter- mined by sensory evaluationa

Number of Treatment observations Tendernessb Juicinessb Flavorb

Nonfat dry milk 66 5.4a 5.0bc 5.3bc Dry whey ’ 66 5.6a 5.4ab 5.7a WPC-1520 66 5.la 4.7c 5.lc WPC-3035 66 5.8a 5.5a 5.6ab

a Values within columns followed by the same I,etters are not differ- ent (P > 0.05) according to the multiple range test (Duncan, 1,955).

b 1 = extremely undesirable, 8 = extremely desirable.

Table &Market prices of dry skim milk, dry whey, and whey pro- tein concehtrates (Nov.. 19781

Raw material Price Difference in price com- pared to nonfat dry milk

Nonfat dry milka Dry wheya WPC-I 52ob wprxo35b

-----:-, ------ $/lb ______ --I-G ----

0.75 0.00 0.18-0.20 -0.55

0.49 -0.26 0.55 -0.20

? Dairy Record, 1.978. h Supplied by manufacturer.

Loaves containing WPC-3035 were rated significantly more desirable in juiciness than those containing the NDM and WPC-1520. Ratings did not differ between NDM and WPC-I 520, or between dry whey and control (P < 0.05).

Loaves containing dry whey were rated higher than the NDM and WPC-1520 loaves in ‘desirability of flavor, but were not different from WPC-3035. WPC-1520 and NDM were not different (P < 0.05).

’

DISCUSSION TENDERNESS VALUES as measured by shear-force read- ings were in agreement with sensory panel ratings of tender- ness since no significant differences were found ‘among treatments with either test. This indicates that NDM, dry whey and WPC’s possessed the same binding strength after incorporation into meat loaves.

Differences in samples as determined by the triangle test were apparently due primarily’ to variations in juiciness and flavor, since the taste panel had no preference for tender- ness in any sample (Table 5). The ratings for juiciness -and flavor in approximate order were WPC-3035, dry whey, controLand WPC-1520. z

Desirability ratings for juiciness and flavor could result from ‘two <different factors. The family loaf made with WPC-3035 contained the highest level of whey- proteins which ‘have beeh shown to have good water binding proper- ties (Delaney,’ 1976; McDonough et ai., 1974; Morr et a!., 1973). On’ the other hand, dry whey contributed a high level of lactose which acts as a flavor enhancer (Gillies, 1973). This suggests that a whey concentrate containing both lactose and whey proteins would be a desirable prod- uct for use in family loaf.

,Overall, the use of dry whey or WPC-3035 resulted in a juicier, more flavorful family loaf product when compared with NDM: Current prices for the dairy ingredients (Table 6) indicated. that from an economic point of view, dry whey would be the least costly. From a nutritional stand- point, however, the WPC-3035 gave the same content of protein as NDM and was rated more desirable by the senT sory panel. The higher protein content in family loaf made with WPC-3035 as compared to dry whey would probably

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