Location: Market Quality and Handling ResearchTitle: Influence of Bleaching on Flavor of 34% Whey Protein Concentrate and Residual Benzoic Acid Concentration in Dried Whey Proteins Author
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2011
Publication Date: 9/9/2011
Citation: Listiyani, M.A., Campbell, R.E., Miracle, R.E., Dean, L.L., Drake, M.A. 2011. Influence of Bleaching on Flavor of 34% Whey Protein Concentrate and Residual Benzoic Acid Concentration in Dried Whey Proteins. Journal of Dairy Science. 94(9):4347-4359. Interpretive Summary: Whey protein is a by product of cheese manufacturing. Due to the presence natural and added coloring agents, whey often needs to be bleached before use in other products. This research compared the bleaching power of benzoyl peroxide to hydrogen peroxide in whey removed from the production of cheddar cheese. Although benzoyl peroxide was more effective than hydrogen peroxide in the bleaching process and resulted in lower amounts of undesirable flavor, higher levels of benzoic acid were present in the bleached product. Although the US does not have set limits for benzoic acid in whey at present, export of benzoyl peroxide bleached whey could be limited to other nations if the benzoic acid levels were too high. It was also found that the levels of benzoic acid could be reduced by ultrafiltration of the whey before drying, however this may make the dried whey product less economically appealing.
Technical Abstract: Previous studies have shown that bleaching negatively affects the flavor of 70% whey protein concentrate (WPC70), but bleaching effects on lower-protein products have not been established. Benzoyl peroxide (BP), a whey bleaching agent, degrades to benzoic acid (BA) and may elevate BA concentrations in dried whey products. No legal limit exists in the United States for BP use in whey, but international concerns exist. The objectives of this study were to determine the effect of hydrogen peroxide (HP) or BP on bleaching the flavor of 34% WPC (WPC34) and to evaluate residual BA in commercial and experimental WPC bleached with and without BP. Cheddar whey was manufactured in duplicate. Pasteurized fat-separated whey was subjected to hot bleaching with either HP at 500 mg/kg, BP at 50 or 100 mg/kg, or no bleach. Whey was ultrafiltered and spray dried into WPC34. Color [L* (lightness), a* (red-green) and b* (yellow-blue)] measurements and norbixin extractions were conducted to compare bleaching efficacy. Descriptive sensory and instrumental volatile analyses were used to evaluate bleaching effects on flavor. Benzoic acid was extracted from experimental and commercial WPC34 and 80% WPC (WPC80) and quantified by HPLC. The b* value and norbixin concentration of BP-bleached WPC34 were lower than HP-bleached WPC34. Hydrogen peroxide-bleached WPC34 displayed higher cardboard flavor and had higher volatile lipid oxidation products than BP-bleached or control WPC34. Benzoyl peroxide-bleached WPC34 had higher BA concentrations than unbleached and HP-bleached WPC34 and BA concentrations were also higher in BP-bleached WPC80 compared with unbleached and HP-bleached WPC80, with smaller differences than those observed in WPC34. Benzoic acid extraction from permeate showed that WPC80 permeate contained more BA than did WPC34 permeate. Benzoyl peroxide is more effective in color removal of whey and results in fewer flavor side effects compared with HP and residual BA is decreased by ultrafiltration and diafiltration.