Dept. of Food, Bioprocessing, and Nutrition Sciences, Southeast Dairy Foods Research Center, North Carolina State Univ., Raleigh, NC 27695, U.S.A.
J Food Sci. 2014 Jan;79(1):C19-24. doi: 10.1111/1750-3841.12279. Epub 2013 Dec 13.
Previous research has demonstrated that unit operations in whey protein manufacture promote off-flavor production in whey protein. The objective of this study was to determine the effects of feed solids concentration in liquid retentate and spray drier inlet temperature on the flavor of dried whey protein concentrate (WPC). Cheddar cheese whey was manufactured, fat-separated, pasteurized, bleached (250 ppm hydrogen peroxide), and ultrafiltered (UF) to obtain WPC80 retentate (25% solids, wt/wt). The liquid retentate was then diluted with deionized water to the following solids concentrations: 25%, 18%, and 10%. Each of the treatments was then spray dried at the following temperatures: 180 °C, 200 °C, and 220 °C. The experiment was replicated 3 times. Flavor of the WPC80 was evaluated by sensory and instrumental analyses. Particle size and surface free fat were also analyzed. Both main effects (solids concentration and inlet temperature) and interactions were investigated. WPC80 spray dried at 10% feed solids concentration had increased surface free fat, increased intensities of overall aroma, cabbage and cardboard flavors and increased concentrations of pentanal, hexanal, heptanal, decanal, (E)2-decenal, DMTS, DMDS, and 2,4-decadienal (P < 0.05) compared to WPC80 spray dried at 25% feed solids. Product spray dried at lower inlet temperature also had increased surface free fat and increased intensity of cardboard flavor and increased concentrations of pentanal, (Z)4-heptenal, nonanal, decanal, 2,4-nonadienal, 2,4-decadienal, and 2- and 3-methyl butanal (P < 0.05) compared to product spray dried at higher inlet temperature. Particle size was higher for powders from increased feed solids concentration and increased inlet temperature (P < 0.05). An increase in feed solids concentration in the liquid retentate and inlet temperature within the parameters evaluated decreased off-flavor intensity in the resulting WPC80.
先前的研究表明，乳清蛋白制造过程中的单元操作会促进乳清蛋白产生异味。本研究的目的是确定液体浓缩物中进料固含量和喷雾干燥器入口温度对干乳清蛋白浓缩物（WPC）风味的影响。用切达干酪乳制造、脱脂、巴氏杀菌、漂白（250ppm 过氧化氢）和超滤（UF）得到 WPC80 截留物（25%固含量，wt/wt）。然后用去离子水将液体截留物稀释至以下固含量：25%、18%和 10%。将每种处理分别在以下温度下喷雾干燥：180°C、200°C 和 220°C。该实验重复了 3 次。通过感官和仪器分析评估 WPC80 的风味。还分析了颗粒大小和表面游离脂肪。研究了主要效应（固含量和入口温度）和相互作用。与 WPC80 在 25%进料固含量下喷雾干燥相比，在 10%进料固含量下喷雾干燥的 WPC80 具有更高的表面游离脂肪、更高的整体香气、白菜和纸板风味强度以及更高的戊醛、己醛、庚醛、壬醛、（E）-2-癸烯醛、DMTS、DMDS 和 2,4-癸二烯醛浓度（P<0.05）。在较低入口温度下喷雾干燥的产品也具有更高的表面游离脂肪和更高的纸板风味强度以及更高的戊醛、（Z）-4-庚烯醛、壬醛、壬醛、2,4-壬二烯醛、2,4-癸二烯醛和 2-和 3-甲基丁醛浓度（P<0.05）与在较高入口温度下喷雾干燥的产品相比。粉末的粒径随进料固含量和入口温度的增加而增加（P<0.05）。在评估的参数范围内，液体浓缩物中进料固含量的增加和入口温度的增加降低了所得 WPC80 中的异味强度。
