| The soybean powder was production obtained from soybean after deodorization, sterilization and spray processing. In this processing the solubility function of soybean protein was damaged, such as the reduction of NSI value and the lower of dispersibility, so limiting the application of soybean powder in foods, due to a certain degree of thermal denaturation of protein caused by overheating. In this study, biological enzymolysis technology was adapted to moderately degrade protein molecular of soybean.The soybean powder with better solubility was developed, expecially in the infant formula powder. The soybean powder not only solve the baby’s lactose intolerance and milk protein allergy, but also expand the application scope of the instant soybean powder in the foods.The main research contents1. In this study, wet processing was adopted to produce instant soybean powder,soybean after soaked and drained was blanched, grinded and mashed. The optimum conditions of blanched were determined85℃and keep4min through the research of heat treatment. The optimum conditions of grinding were obtained85℃,bean to water ratio was1:7,sodium bicarbonate addition was0.3%.The optimum boiling conditions were gotten95℃,and keep20min.The boilied soymilk was cooled to a certain temperature, then the Neutral protease and papain enzyme were respectively added to enzymatic it, pH, hydrolysis temperature, hydrolysis time and enzyme dosage were chosen as influencing factors. The Papain was the optimum experiment enzyme choosed through the comparative analysis, the optimum conditions:pH was6.92, addition of enzyme was8764.54U/g, enzymatic temperature was54.34℃,enzymatic time was110.4min.Under the optimum conditions, the forecasting NSI value was86.3149%,and practical determination was85.83%,DH value was attained4.62%and soybean milk was without bitter taste. After the enzymatic hydrolysis the soybean milk was sterilized under121℃for15min,then was concentrated under vaccum condition,homoginized,spray dried.The optimum conditions:concentration temperature was55℃,rotating RPM was50r.p.m,the vaccum degree was0.09MPa,time was20min.The optimum homogeneous conditions were one time homogeneous pressure26MPa, two times homogeneous pressure10MPa.After the homogeneous,soybean milk was spray dried, thereby obtaining the instant soybean powder.2. Research of mixed formula powder: mixed formula powder was obtained through added the instant soybean powder to the infant formula milk powder by a certain percentage, taking the NSI value as index, the optimum addition amount was finally determined23%.Solubility and digestibility of the mixed formula powder(instant soybean powder addition23%) were better and improved, and had both milk flavor and soybean flavor, suiting to the special infant with lactose intolerance.3. The experiments of vitro digestion stimulation (determination of the gastrc,intestinal digestion and digestibility):the four simples were instant soybean powder, infant formula milk powder, weiwei soybean powder and soybean powder mixed powder(instant soybean to infant formula powder rate23%). Compared determination results of vitro gastric, intestinal and digestibility, it was demonstrated that the instant soybean powder> mixed formula powder> infant formula powder> weiwei soybean powder. The results of the vitro digestion simulation experiments was consistent4. Protein nutrition value experiments of the four simples (the instant soybean, infant formula, weiwei, instant soybean to infant formula powder rate23%) was evaluated after vitro digestion and compared with baby reference mode and FAO/WHO. The results demonstrated the four samples have high nutrition value, while appropriate methionine, tryptophan and other essential amino acids in order to achieve a balanced nutrition. |
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