Study On The Technology For Improving The Flavor Of Soybean Peptide

Compared with soybean protein, soybean peptides have more superior physicochemical properties and bioactivities, and which have good prospects of application in many area. However, the odor flavor, produced in the production and processing of soybean peptides, which limit its application. This article studied the odor flavor of soybean peptides to explore the causes and hope to improve or even eliminate odor flavor.Proceed from the solid-state fermentation stage of the study, detect the parameters of the fermentation, analyze the causes of odor flavor, we found that the odor flavor relate to the raw material soybean meal, and the emergence of Bacillus has some relevance with the emergence of odor flavor of soybean peptides.Through the test, we found that the odor flavor can be significantly reduced by the mixed fermentation with Bacillus subtilis and Yeast. The mixed fermentation process optimization are:in the fermentation stage, Bacillus subtilis 0.3‰,Yeast 1.5‰,soluble starch addition level 3%,materials-water ratio 1:0.6,30℃2 days;in the hydrolysis stage, materials-water ratio 1:7,50℃,7 h.A gas chromatography-mass spectrometry (GC-MS) was used to identify the flavor compounds from soybean peptides isolates by headspace solid-phase microextraction (HS-SPME).Alcohols, aldehydes and ketones have high levels, and which had 77.07-94.64% to total material content, 1-octen-3-ol,one of the main odor-flavor compounds in defatted soy products, had decreased.2-methyl-furan,hexanal, 1-pentene-3-ol,2-heptanone,2-hexanol,6-octene-2-one,3-octanol, (R)-2-octanol, 2-decanone, benzaldehyde,2-undecanone and phenol had increased during the fermentation, and these compounds may form the odor-flavor of soybean peptides.A new method was established to determine the odor flavor in soybean peptides by ultraviolet spectrophotometry. The optimized conditions are as follows:the sample pH 6.0, NaCl 4g/60mL,60ml sample in 100ml Saline bottle,50℃for 1 hour, and then extract 20ml gas in the bottle into 5ml 0.2mol/L NaOH, detect the absorption value at 217nm. This method is simple and quick, which can be applied to detect disgusting odor in soybean peptides.