Effects Of Soybean Protein On The Quality Of Milk And Milk Beverage

With the fast development of soybean industry, the quality of soybean protein products are being improved a lot, and their applying value is soaring greatly as well. With high nutritional value and good functional properties, soybean protein made by special technology couldn't deteriorate milk's nutrition and acceptance. Instead, it enriches the sorts of milk with improving quality.This paper chooses proper kinds of protein for milk and milk beverage, and also optimizes parameters of the preparing technology. At the same time, we analyze the soy protein's flavor and color. The effects of soybean protein on the milk's flavor and color are being studied as well. Study shows soybean protein isolated made from soybean meal being washed by 95% alcohol has good solubility and emulsification properties. And its flavor and color is better than other kinds of protein as well. So such kind of soybean protein is a kind of great stuff for adding to liquid milk. The results of GC-MS show that such kind of protein has little beany flavor than other kinds of soybean protein, so it has better flavor. In addition, the pigments related to soybean protein are mainly water-soluble polyphenol, out of which isoflavones are the most important, such as genistein, daidzin and so on. Such kinds of polyphenol are mainly bounded to protein. And polyphenolic acids are not only oxidated to form coloring materials, but also bring astringency and bitter taste to the protein. Washing soybean meal with alcohol could diminish polyphenol in soybean protein as well, free polyphenol in particular.Results show that 70℃and 30MPa are the best condition for homogenizing, and being sterilized under"121℃, 15min"have good stability and long shelf-life. The protein content of neutral dual-protein milk and acid dual-protein milk beverage are 3% and 1%. We think pH4.0, 8% of sucrose and mixed acid made by citric acid, lactic acid and malic acid in accordance with the proportion of 1:2:1 are the most suitable condition for the taste of the acid milk. Calcium source is important for both the casein and soy protein. Because ionized calcium would make these two kinds of protein thermally instable, we choose Calcium Citrate(molecular calcium)as our calcium source. Taking the international definition of high-calcium milk for refence, we choose 0.66g/100mL as our adding volume, and the final calcium content in our product is 1.42mg/mL.