Study On Processing Technology Of Physalis Tofu

Yellow pulp water is one of the high yield by-products in the production of soy foods with high nutrition.Yellow pulp water can be acidified into acid-fluid by microbial fermentation under natural conditions.Tofu made with the acid s fluid?physalis Todu in short?is popular in southeast part of China,because of its unique and delicate taste.However,physalis tofu is mostly produced by small workshops until now.The judgment of the termination of physico-fermentation is determined by worker's experience,and accurate scientific mothed is still lacked.Moreover,the quality of the is easily affected by the environment.Due to the uncertainty of sampling time and location,the quality of the naturally fermented physalis is not stable,which seriously restricts the development of the industrialization of the acid-fluid tofu.In this paper,the yellow pulp water from dried Tofu production is used as the culture medium,to prepare the acid-fluid by single or double bacteria fermentation with Lactobacillus plantarum and P.Acetobacter,respectively.The preparation of physalis is optimized.Then the protein change during the formation of tofu gel is studied,and the gel characteristics,sensory characteristics and flavor components of the acid-fuild tofu are characterized.Finally,the quality of the experimental physalis tofu was compared with the physalis tofu sold in Yunnan.And sensory acceptance was evaluated.The main research contents and results are as follows:The main study content and findings are as follows:1.Ingredient analysis of yellow pulp water and selection of raw materials for physalis:The protein,reducing sugar,metal ion content,color difference,and stability index of three different yellow pulp waters of tofu,and thousand sheets were measured.Determination of seven organic acids in three yellow pulp waters by High Performance Liquid Chromatography?HPLC?.The contents of reducing sugar,metallic Ca²⁺and organic acids in the dried soybean milk water were?0.21±0.02?mol/mL,?7.49±0.07??g/mL and?408±0.21??g/mL.Combined with the growth of the bacteria in the dried soybean and thousands of yellow pulp water,it is comprehensively determined that the dried soybean milk is the most suitable medium for the fermentation of the bacteria.2.Study on the process of preparing acid-fluid from different strains.Lactobacillus plantarum and P.baumannii were used to carry out single-bacteria and double-bacteria fermentation of yellow pulp water.The number of colonies and acidity were used as indicators,and the optimal sulphur production process was obtained by comprehensive scoring method.The content of organic acids is combined to obtain the best acid slurry processing technology.When the glucose is 0.8%,and the inoculum is 8%,and the fermentation conditions are 48 h and 34°C,the yield of physicochemical pulp from the fermentation of yellow yeast water by Lactobacillus plantarum is the largest.In addition,the organic acid content of bean curd yellow pulp water was significantly increased after fermented by Lactobacillus and P.baumannii,and lactic acid and acetic acid showed the biggest changes among the organic acid in physalis.3.Study on the formation of physalis tofu gel and process optimization.The change of protein in the formation of physalis tofu gel was studied.At the same time,the ratio of soaked soybean to water for grinding,the amount of coagulant added and the sizing temperature in the syrup tofu preparation process were optimized.As an indicator,combined with sensory evaluation to determine the best conditions.The results show that during the formation of tofu gel,the protein response is mainly 11S protein at 0¹0 min,and 7S protein is the main reaction after 10 min.The protein secondary structure of yoghurt tofu mainly exists in the form of?-sheet and?-turn.The best preparation process conditions for the trial production of syrup tofu are that the ratio of soaked soybean to water is 1:5,the pulp temperature is 85°C,and the added amount of physalis is 10%.Comparing the quality of the trial physalis tofu with the commercial physalis tofu,it can be found that the gel strength and water holding capacity of the commercially available tofu were consistent with the experiment of syrup tofu and the results of scanning electron microscopy.Gas chromatography-mass spectrometry?GC-MS?was used to determine the flavor components of the physico-cured tofu and the commercially available physalis tofu.When the matching degree is>90%,the flavored substances in the acid-fluid tofu were more than the commercial physalis.The flavor substance in the tofu combined with cluster analysis shows that the main flavor substance in the two physalis tofu is 2-n-pentyl furan.The sensory qualities of the experimental acid-fluid tofu and the commercially available physalis tofu are similar.