Abstract: Spray-dried whey protein powders were produced from whey obtained as a by-product in the production of milk cake and milk fan as ethnic dairy products in Yunnan, and their main components and processing characteristics were analyzed. The results showed that the main components of whey protein powder obtained from the by-product of milk cake were protein 39.0%, fat 6.0%, moisture 4.1%, total ash 7.7%, acidity 23.2 °T, and pH 5.61, and the processing characteristics were 99.52% solubility, less than 3.2% precipitation at different temperatures, and emulsifying activity index (EAI) and emulsion stability index (ESI) both greater than 42.7% at different pH values. The main components in whey protein powder obtained from the by-product of milk fan were protein 72.0%, fat 19.8%, moisture 4.6%, total ash 8.1%, acidity 58.3 °T, and pH 5.20, and its processing characteristics were 98.70% solubility, less than 3.5% precipitation at different temperatures, and EAI and ESI both higher than 50% at different pH values. The sensory scores of yogurts with the two whey protein powders were 70.7 and 72.7 out of 100 points, respectively, indicating that both can be used as an ingredient in yogurt.

Key words: milk cake; milk fan; whey; whey protein powder; physicochemical parameters; processing characteristics

摘要： 乳饼、乳扇是云南民族特色乳制品，以二者的加工副产物乳清为原料，通过冷冻干燥技术制得乳清蛋白粉，分析其主要成分及加工特性。结果表明：乳饼副产物获得的乳清蛋白粉中主要成分蛋白质含量39.0%、脂肪含量6.0%、水分含量4.1%、总灰分含量7.7%、酸度23.2 °T、pH 5.61，其加工特性为溶解性99.52%，沉淀率在不同温度下均小于3.2%，乳化活性指数（emulsifying activity index，EAI）和乳化稳定性指数（emulsion stability index，ESI）在不同pH值下均大于42.7%；乳扇副产物获得的乳清蛋白粉中主要成分蛋白质含量72.0%、脂肪含量19.8%、水分含量4.6%、总灰分含量8.1%、酸度58.3 °T、pH 5.20，其加工特性为溶解性98.70%，沉淀率在不同温度下均小于3.5%，EAI和ESI在不同pH值下均大于50%。将乳扇乳清蛋白粉和乳饼乳清蛋白粉添加到酸乳中，酸乳感官评分分别为70.7 分和72.7 分。因此，2 种乳清蛋白粉均能够应用于酸乳加工。

关键词: 乳饼；乳扇；乳清；乳清蛋白粉；理化指标；加工特性