The Use of Whey Protein Concentrate in Baked Products

The Use of Whey Protein Concentrate in Baked Products Lauren Henchy Experimental Study of Food April 20, 2009

1 In the United States, protein is used by many athletes and body builders as the primary source for muscle building when it comes to training. Protein is also a popular macro-nutrient to be added to beverages and certain meal-replacement products. Protein is most commonly substituted into certain foods and beverages in the form of a whey protein concentrate (WPC). Whey protein is a more popular choice than soy protein with consumers because whey is noted for having more of a sweet aroma and a sweet, vanilla flavor when compared with soy protein (1). Whey protein also contains essential amino acids which make it a complete source of protein (2). Typically, WPC is consumed in drink mixes or meal bars that can be found in health stores. The purpose of this paper is to explore the substitution of WPC into foods other than popularly consumed powdered beverage mixes and meal bars. The addition of WPC and how it will increase protein levels in foods, specifically wheat-based products and baked goods, will be explored. Preparation methods, handling techniques and treatments, baking properties and flavor of WPC, as well as a comparison between soy and whey protein will be discussed. Flavor is a highly important quality to factor into the decision of adding any type of whey protein to a baked product. However, deciding which protein supplement to use can affect the overall acceptance of a product. Several comparison studies, using consumer acceptance testing, between whey and soy protein were performed. Researchers in the first study kept in mind that flavor of both whey and soy proteins are important when it comes to forming a great tasting, healthy product. A poll of 147 consumers was taken which was meant to identify their opinions and thoughts toward dairy and soy products (2). The results of the survey indicated that consumers generally felt that dairy products were better tasting than soy products, but that both had unique and individual health benefits associated with them (2). The consumers were polled and results indicated that 20% agreed soy products tasted great compared to 63% of consumers who polled that dairy products tasted great (2). These results indicated that whey protein, in any particular form, would be a better choice over soy protein, when it comes to supplementing a product with protein to increase the nutritional value, because whey is more

2 widely accepted. A second study was performed to investigate the sensory qualities of meal replacement bars and beverages made with both whey and soy protein through evaluation by a trained taste panel. This study also involved consumer acceptance testing and was done to further promote research on which product, whey or soy, is more a more acceptable addition. Meal bars and beverages were purchased for consumers, n=85, and prototype meal bars and beverages were formulated by the researchers for trained panelists, n=8, to evaluate (1). The researcher formulated bars and beverages, for the trained taste panelists, which contained either 100% whey protein, 100% soy protein, 50/50 whey and soy protein, or neither whey nor soy protein. The prototype bars and beverages were designed to mimic the commercially purchased bars and beverages (1). Scores from the panelists showed that bars made with 100% whey protein had a more vanilla and nutty flavor and a sweet aroma when compared with 100% soy bars and 50/50 whey/soy bars (1). Overall mouth-feel of the 100% whey bars were preferred over the 100% soy bars because the whey bars had a more dense and cohesive structure while the soy bars left more particles in the mouth after chewing (1). The results of the panelists indicated that they preferred the bars and beverages formulated with 100% whey protein over the 100% soy protein. Consumer testing indicated almost identical results with the lab formulated bars. Consumers felt that the whey bars had a more intense sweet aroma than the soy bars and that the texture of the whey bars were more acceptable because they left fewer particles in the mouth (1). Panelists and consumers also indicated that the beverages were not appealing nor were they well liked, but when asked to choose one they chose the 100% whey protein beverage over the 100% soy (1). The results of these studies affirmed that whey protein is a more acceptable protein to use in meal bars and beverages which can help aide researchers in designing products using whey protein for consumers who desire optimal sensory qualities. As seen in the previous comparisons between whey and soy protein supplements, flavor plays a

3 large role in acceptance when it comes to determining a product's success on the market. Using the optimal type of whey protein is an important factor to consider when supplementing a baked product with protein. A group of researchers performed two separate studies comparing the sensory properties of WPC and whey protein isolates (WPI). Dried ingredients, such as whey protein concentrate (WPC), can impact a finished product s overall quality based on its flavor and flavor variability. The flavor of whey solids, like WPC, has been considered a primary factor in causing limited use in food products. The USDA states that dry whey should have a normal whey flavor and be free from undesirable flavors, allowing room for varying flavor notes such as bitter, weedy, and fermented (3). Off flavors can occur in foods with added WPC because of maillard browning, which is caused by a reaction between certain amino groups and reducing sugars, usually requiring heat. The comparison between WPI and WPC began with the testing of WPC and WPI sources that were extracted from several different types of cheeses. The second study tested WPC and WPI sources that used processing techniques such as benzoyl peroxide bleaching and instantizing to see if these chemical processes affected flavor. The two studies used a panel consisting of eleven members who tested the sensory properties of these forms of WPC and WPI. A 10-point line scale using grading characteristics from none to extremely intense was used (3). The results of the study showed that panelists rated WPC samples higher than WPI samples for flavor because the samples of WPC had a more intense milky, sweet, and caramel flavor (3). WPC that was extracted from a cottage cheese sample was noted for having a more bitter and sour flavor note, which was caused by the high acidity of cottage cheese whey (3). Panelists low score of optimal flavor for WPC extracted from cottage cheese can prove to be useful in helping find better ways to use WPC in food products and reduce poor or off flavor notes. Panelists also noted no difference in sensory qualities between WPC and WPI bleached with benzoyl peroxide and instantized. These results affirmed that processing techniques used to manufacture WPC and WPI did

4 not affect flavor characteristics. WPC products were also noted by panelists to have a sweeter flavor due in part to WPC's higher concentration of lactose as well as milkier flavor/texture due to higher concentrations of milk fat (3). The results of these studies prove that if a sensory panel was unable to detect differences in flavor between products that used the mentioned processing techniques, as well as give high flavor ratings for WPC, then WPC may be an acceptable additive in food products. In order to evaluate the outcome of adding WPC to baked products, a study analyzing the affects of WPC on biscuits was researched. Biscuits were used in this study because they are noted for having a longer shelf life making them more convenient for testing purposes. Biscuits have been regarded as an unhealthy food because of their high fat and sugar content. However, enriching biscuits with a dairy protein source would help increase their nutritional and functional benefits. These benefits would include increased calcium content and supplementation of essential amino acids like lysine and typtophan (4). Researchers prepared biscuit dough with 0, 5, 11, or 25% of WPC 40 (36.4% protein) or WPC 80 (68% protein). The ph, firmness, consistency, adhesiveness, and cohesiveness of the dough were measured. The dough that contained 5% of the WPC 80 mixture resulted in a decrease in the firmness and consistency of the dough but increased the cohesiveness. The final biscuit products differed because WPC 80 had a higher lactose concentration and contained about 50% more protein than WPC 40. Elasticity of the dough was reduced by the addition of both WPC 40 and WPC 80 but was due, in part, to the fact that whey proteins interfere with the normal structure of the gluten by reducing its ability to fully develop (4). These results concluded that WPC is an acceptable addition to biscuits because of its ability to increase cohesiveness in the dough and reduce stress fracture during baking. This would prove that WPC, in varying protein levels, could be an acceptable addition into a baked product to enhance its nutritional value with the increased calcium and protein content, as well as providing supplementation of several essential amino acids. The addition of WPC to baked goods was further evaluated in the following studies which add

5 several forms of treated and untreated WPC to baked products like cookies and breads. The first study analyzes the addition of commercial WPC (CWPC) treated with heat and high hydrostatic pressure (HHP) into wheat flour in the amount of 5 and 10% flour replacement. The effects of these additions on the quality of bread and cookies were studied. Cookies were prepared from soft wheat flour that was fortified with either 5 or 10% CWPC and the final products diameter was measured (5). Bread was prepared using a combination of wheat flour and untreated or HHP treated CWPC; the volume and hardness of the bread were measured (5). Researchers noted that the diameter of the cookies increased with the addition of 5% untreated CWPC while the addition of 10% untreated CWPC had no effect on the diameter (5). Cookies treated with heat and HHP CWPC caused a decrease in the diameter. Cookie diameter increased with untreated CWPC because the gluten structure weakens from interactions between whey and wheat proteins (5). The bread results indicated that with the addition of 10% CWPC the loaf volume decreased which was caused by a dilution of the gluten strands from the proteins in the CWPC (5). Bread with added CWPC also produced a more hard loaf compared with the control. However, the protein content in the bread increased from 14.8 to 17.6% with the addition of 5% CWPC and to 20.2% with the addition of 10% CWPC (5). The best results were achieved with the addition of 10% CWPC which also caused an increase in the protein content as well as the essential amino acid content of the products. Although some negative qualities were attained when incorporating WPC, the increased protein and amino acid content may have helped overcome these results. The second study added heat treated WPC to frozen dough in an attempt to prevent the weakening of the gluten structure. WPC was dissolved in distilled water to make a 5% whey protein solution to be added to the dough. The WPC was heat treated in order to denature the whey protein and reduce its solubility to prevent negative outcomes in bread-making which were seen in the previous study. The dough was composed of wheat flour, dried yeast, fat, with the addition of WPC at 75% protein content (6). The WPC was heat treated at 82ºC and 84ºC which improved the overall baking

6 performance of the frozen dough by decreasing the time it took for the yeast to ferment and the bread to rise as well as decreasing the firmness of the crumbs. Researchers baked several samples of bread, a control, a loaf with untreated WPC, and a loaf with heat treated WPC at either 82ºC or 84ºC. The loaf with the untreated WPC was noted for having a decrease in volume while the heat treated WPC had a significantly higher volume than the untreated. Researchers noted that untreated WPC had negative effects on the dough and baking properties but when the WPC was heated, the negative effects were eliminated (6). Researchers also noted that the optimal temperature to denature the WPC was at 82ºC because it produced the best results during the experiment. However, heat treated WPC did not improve baking performance in general when compared with the control. Furthermore, it is noted that if one were to improve the protein and essential amino acid content in a baked product, such as cookies or breads, the optimal way to do this would be to replace 5% of the wheat flour with heat treated WPC. Untreated WPC may interfere with the gluten network and produce bread that has poor baking performance. In conclusion, it can be said that the addition of WPC may be an acceptable nutritional enhancer, in terms of protein and essential amino acid content, when it is properly treated and used. Untreated WPC should be used sparingly, with the replacement of 5% of the flour at most considering the negative affects it can have on the baking performance of the product. WPC should be dissolved in water and heat treated in order to obtain optimal baking performance in a bread product. Based on scores and ratings of panelists and consumers, it is clearly seen that the addition of WPC to a product had more general acceptance than a product fortified with soy protein. This indicates that flavor plays, perhaps, the biggest role when it comes to the acceptance of a WPC fortified product. A sweet, vanilla aroma and a cohesive and dense texture have more appeal to a consumer than a product which may leave particles left over in the mouth. WPC was also shown to have improved the adhesive/cohesive properties of biscuits as well as improve the calcium and essential amino acid content. Further

7 research is still necessary to formulate WPC which will perform more effectively in baked products, as well as determining which preparation method and handling technique will produce an optimal WPC fortified baked product. However, WPC may still be used sparingly to fortify these products with calcium and protein without detracting from flavor or baking performance.

8 Bibliography 1. Childs JL, Yates MD, Drake MA. Sensory properties of meal replacement bars and beverages made from whey and soy proteins. J Food Sci. 2007; 72: 425-434. 2. Conforti PA, Lupano CE. Functional properties of biscuits with whey protein concentrate and honey. International J Food Sci. 2004; 39: 745-753. 3. Kadharmestan C, Byung-Kee B, Czuchajowska Z. Whey protein concentrate treated with heat or high hydrostatic pressure in wheat-based products. Cereal Chemistry. 1998; 75: 762-766. 4. Kenny S, Wehrle K, Auty M, Arendt EK. Influence of sodium caseinate and whey protein on baking properties and rheology of frozen dough. Cereal Chemistry. 2001; 78: 458-463. 5. Mortenson MA, Vickers ZM, Reineccius GA. Flavor of whey protein concentrates and isolates. International Dairy Journal. 2008; 18: 649-657. 6. Russell TA, Drake MA, Gerard PD. Sensory properties of whey and soy proteins. J Food Sci. 2006; 71: 447-455.

9 End Note Citations 1. Childs JL, Yates MD, Drake MA. Sensory properties of meal replacement bars and beverages made from whey and soy proteins. J Food Sci. 2007; 72: 425-434. 2. Russell TA, Drake MA, Gerard PD. Sensory properties of whey and soy proteins. J Food Sci. 2006; 71: 447-455. 3. Mortenson MA, Vickers ZM, Reineccius GA. Flavor of whey protein concentrates and isolates. International Dairy Journal. 2008; 18: 649-657. 4. Conforti PA, Lupano CE. Functional properties of biscuits with whey protein concentrate and honey. International J Food Sci. 2004; 39: 745-753. 5. Kadharmestan C, Byung-Kee B, Czuchajowska Z. Whey protein concentrate treated with heat or high hydrostatic pressure in wheat-based products. Cereal Chemistry. 1998; 75: 762-766. 6. Kenny S, Wehrle K, Auty M, Arendt EK. Influence of sodium caseinate and whey protein on baking properties and rheology of frozen dough. Cereal Chemistry. 2001; 78: 458-463.