Department of Food, Bioprocessing, and Nutrition Sciences, Southeast Dairy Foods Research Center, North Carolina State University, Raleigh 27695, USA.
J Dairy Sci. 2009 Dec;92(12):5917-27. doi: 10.3168/jds.2009-2535.
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.
乳清蛋白作为一种成分的使用和需求不断增加，这就需要最终产品具有无味、中性的颜色。为了达到这一目标，需要对有色切达干酪乳清进行漂白。目前，在喷雾干燥之前，过氧化氢（HP）和过氧化苯甲酰（BPO）用于液体乳清的漂白。目前没有关于漂白过程对喷雾干燥乳清蛋白粉（WPC）风味影响的信息。本研究的目的是研究漂白对液体和喷雾干燥切达干酪乳清风味的影响。用可溶于水的胭脂树橙为奶酪上色，重复制造了两份。对液体乳清进行了 4 种漂白处理（HP，250 和 500mg/kg 和 BPO，10 和 20mg/kg），在 60°C 下处理 1.5 小时，然后冷却至 5°C。还评估了一种没有漂白剂的对照乳清。通过感官和仪器挥发性分析评估液体乳清的风味。随后选择了一种 HP 处理和一种 BPO 处理，并将其与未经漂白的对照乳清一起加入液体乳清中，未经漂白的对照乳清被加工成喷雾干燥的 WPC。这些试验重复进行了 3 次。通过感官和仪器分析以及颜色和近似分析评估 WPC。与未经漂白或 BPO 漂白的液体乳清或 WPC 相比，HP 漂白的液体乳清和 WPC 含有更高浓度的氧化反应产物，包括庚醛、己醛、辛醛和壬醛。与 BPO 样品相比，HP 产品的总氧化产物更高。与对照或 BPO 样品相比，HP 液体乳清和 WPC 具有更高的脂肪和纸板风味。WPC 粉末的 Hunter CIE Lab 颜色值（L*、a*、b*）在所有 3 个颜色尺度参数上都有明显区别，HP 漂白的 WPC 的 L*值最高。过氧化氢导致 WPC 更白，异味强度更高；然而，HP 和 BPO 之间的 norbixin 回收率没有差异。这些结果表明，液体乳清的漂白可能会影响 WPC 的风味，并且使用的漂白剂类型可能会影响 WPC 的风味。
