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Eur Food Res Technol (2013) 237:377384 DOI 10.1007/s00217-013-2000-3
ORIGINAL PAPER
Bleaching of colored whey and milk by a multiple-enzyme system
Renata T. Szweda Katharina Schmidt
Holger Zorn
Received: 8 February 2013 / Revised: 12 April 2013 / Accepted: 14 April 2013 / Published online: 1 May 2013 Springer-Verlag Berlin Heidelberg 2013
Abstract Carotenoids are broadly used to enhance the color of cheese types like Cheddar and Gouda. While *80 % of the colorants are transferred into the cheese, the rest remains in the whey and impedes its commercial utilization. Therefore, cheese whey is currently bleached chemically by addition of either hydrogen peroxide or benzoyl peroxide in the industrial practice. To avoid heat-and peroxide-induced protein denaturation and the formation of off-avors, an enzymatic bleaching process was developed. The ability of the fungal peroxidase MsP1 to degrade carotenoids was successfully employed for the bleaching of colored whey and milk in two- and three-enzyme systems, respectively. The systems were composed of MsP1, glucose oxidase, and when necessary, acid lactase. The initial step of the three-enzyme system was the lactase-catalyzed hydrolysis of lactose to galactose and glucose. The latter served as a substrate for the enzyme glucose oxidase in the second step which yielded gluconic acid and hydrogen peroxide. Finally, MsP1 oxidatively degraded the carotenoids. The activities of the involved enzymes were ne-tuned to optimize the bleaching process.
Keywords Peroxidase Basidiomycete Bleaching
Annatto b-Carotene
Introduction
Annatto (E 160b) and b-carotene (E 160a) are broadly used to enhance the yellow and orange color of several cheese
types like Cheddar and Gouda. In 2010, *1.5 million tons of Cheddar and 0.5 million tons of dry whey have been produced in the USA [1]. As early as in 1937, Barnicoat analyzed cheese and whey and found that just 8085 % of the colorants were transferred into the cheese, while the rest remained in the cheese whey [2]. Whey offers a range of functional and nutritional properties; it contains soluble whey proteins, lactose, minerals, and vitamins [3]. It may be used to produce meal or egg replacements [4, 5] and whey protein concentrates (WPC). Further options arise from modication of whey proteins by, for example, enzymatic hydrolysis or polymerization [6].
In whey-based drinks, and especially in whey protein concentrates, the colorants are often...