The effect of bleaching agent on the flavor of liquid whey and whey protein concentrate

Abstract

The increasing use and demand for whey protein as an ingredient requires a bland-tasting, neutral-colored final product. The bleaching of colored Cheddar whey is necessary to achieve this goal. Currently, hydrogen peroxide (HP) and benzoyl peroxide (BPO) are utilized for bleaching liquid whey before spray drying. There is no current information on the effect of the bleaching process on the flavor of spray-dried whey protein concentrate (WPC). The objective of this study was to characterize the effect of bleaching on the flavor of liquid and spray-dried Cheddar whey. Cheddar cheeses colored with water-soluble annatto were manufactured in duplicate. Four bleaching treatments (HP, 250 and 500 mg/kg and BPO, 10 and 20 mg/kg) were applied to liquid whey for 1.5 h at 60 degrees C followed by cooling to 5 degrees C. A control whey with no bleach was also evaluated. Flavor of the liquid wheys was evaluated by sensory and instrumental volatile analysis. One HP treatment and one BPO treatment were subsequently selected and incorporated into liquid whey along with an unbleached control that was processed into spray-dried WPC. These trials were conducted in triplicate. The WPC were evaluated by sensory and instrumental analyses as well as color and proximate analyses. The HP-bleached liquid whey and WPC contained higher concentrations of oxidation reaction products, including the compounds heptanal, hexanal, octanal, and nonanal, compared with unbleached or BPO-bleached liquid whey or WPC. The HP products were higher in overall oxidation products compared with BPO samples. The HP liquid whey and WPC were higher in fatty and cardboard flavors compared with the control or BPO samples. Hunter CIE Lab color values (L*, a*, b*) of WPC powders were distinct on all 3 color scale parameters, with HP-bleached WPC having the highest L* values. Hydrogen peroxide resulted in a whiter WPC and higher off-flavor intensities; however, there was no difference in norbixin recovery between HP and BPO. These results indicate that the bleaching of liquid whey may affect the flavor of WPC and that the type of bleaching agent used may affect WPC flavor.

The effect of microfiltration on color, flavor, and functionality of 80% whey protein concentrate

“…2 MF = microfiltration; HP = hydrogen peroxide; LP = lactoperoxidase. 7 on their previous relevance to whey off-flavor (Croissant et al, 2009;Listiyani et al, 2011;Jervis et al, 2012). Consistent with sensory results, HP-and LPbleached WPC80 were more characterized by lipid oxidation compounds, whereas the unbleached and MF WPC80 were characterized by lower concentration of lipid oxidation compounds (Figure 2; Table 4).…”

“…Hydrogen peroxide (maximum usage rate at 500 mg/kg) and benzoyl peroxide (regulated by good manufacturing process, GMP5) are the 2 approved chemical bleaching agents in United States (US FDA, 2013a,b). Chemical bleaching causes lipid oxidation, which results in formation of volatile off-flavors that carry through to final whey protein products (Croissant et al, 2009;Listiyani et al, 2011;Jervis et al, 2012). In addition, it is likely that these oxidants cause oxidation of some AA constituents of protein, which may influence nutritive value and functional properties of whey proteins (Shacter, 2000;Jervis et al, 2012).…”

Sensory and Functionality Differences of Whey Protein Isolate Bleached by Hydrogen or Benzoyl Peroxide

“…A typical WPI process includes fluid storage, clarification/fat separation, pasteurization, bleaching, microfiltration or ion exchange, ultrafiltration, diafiltration, and spray drying (Varnam and Sutherland ; Drake and others ). Bleaching, in particular, has been extensively studied for its detrimental effects on the flavor of whey protein products (Croissant and others ; Listiyani and others ; Campbell and others ; Jervis and others ; Kang and others ). Studies have consistently demonstrated that bleaching with BP results in greater norbixin destruction and less lipid oxidation (and off flavors) compared to HP (Croissant and others ; Listiyani and others ; Fox and others ).…”

“…Bleaching, in particular, has been extensively studied for its detrimental effects on the flavor of whey protein products (Croissant and others ; Listiyani and others ; Campbell and others ; Jervis and others ; Kang and others ). Studies have consistently demonstrated that bleaching with BP results in greater norbixin destruction and less lipid oxidation (and off flavors) compared to HP (Croissant and others ; Listiyani and others ; Fox and others ). Residual benzoic acid (BA) residues remain a concern in whey ingredients bleached with BP due to restrictions in international markets, especially China.…”

Emerging trends in nutraceutical applications of whey protein and its derivatives

“…Currently, hydrogen peroxide and benzoyl peroxide are utilized for bleaching whey before spray drying to produce neutral-coloured whey protein, which often gives off-flavour. Wide usage of whey protein requires a bland-tasting final product (Croissant et al 2009). Lipid oxidation products (hexanal, heptanal, octanal, and nonanal) are primary contributors to the unpleasant odor.…”