Study On Fresh Wet Yuba Joint Preservation Technology And Design Of Annual Production Of 2,000 Tons Of Fresh Wet Yuba Factory

Yuba is a traditional Chinese bean product,rich in high-quality protein,unsaturated fatty acids and isoflavones,phospholipids and other active ingredients.The consumer group and the market demand is large.However,with the changes in consumers' lifestyles,the accelerated pace of life and the changes in the structure of consumer groups,traditional dried yuba is not accepted by consumers because of the inconvenience caused by long time soaking before cooking;At the same time,traditional dried yuba is easy to produce losses in processing,transportation and other processes due to its low water content and high brittleness,which will bring great losses to the production enterprises.Fresh wet yuba(40%-45%moisture content)has gradually gained favor from consumers due to its good flexibility and taste.It has good market potential,but fresh wet yuba is rich in nutrients and high in water content,which is easy to cause the rapid breeding of putrefying bacteria.Therefore,its storage period is very short,which seriously restricts the market development of this product.Therefore,in order to improve the market competitiveness of fresh wet yuba,it is extremely important to preserving the product to extend the shelf life of the product.The research content of this subject includes the optimization of fresh-keeping formula and preservation technology,the determination of product shelf life,the separation and identification of the main spoilage microorganisms in fresh wet yuba,the factory production verification of fresh wet yuba preservation measures,and design of annual production of 2,000 tons of fresh wet yuba factory and related enterprise standard formulation.The main contents are as follows:(1)Determination of suitable moisture content and sterilization conditions for fresh wet yuba.After the fresh wet yuba was producted,according to the relationship between the drying gradient time in the drying chamber at 85? and the moisture content of fresh wet yuba,the sensory evaluation was used as an indicator to determine the dry time when the sensory score of fresh wet yuba was the highest,that is,determine the suitable moisture content of fresh wet yuba.Studies have shown that when the tempernturc in the drying chamber is 85?,the suitable drying time of fresh wet yuba is about 85 minutes,and the water content of the sample is about 43%.In addition,in order to reduce the initial microbial quantity of fresh wet yuba,this topic selects vacuum packaging combined with water bath sterilization method to explore.According to the experimental results,on the basis of vacuum packaging,the optimal water bath sterilization condition is sterilization at 85? for 30 min.At this time,fresh wet yuba does not contaminated by coliform,mold and yeast;the fresh wet yuba is stored at 35? 25? and 4? after sterilization,and the shelf life is about 5 d,7 d and 11d,respectively.(2)Development of fresh wet yuba compound preservative.According to the relationship curve between the citric acid addition and the pH of soybean serum and isoelectric point of soybean protein,based on the sensory evaluation and the precipitation point of soybean slurry,the appropriate addition of citric acid was 0.20%of the weight of the product.Using sensory evaluation and total number of colonies as indicators,the preservation effect of sodium propionate,?-polylysine hydrochloride and citric acid leaching concentration(soaking time of 2 min)on fresh wet yuba was studied.The results of single factor preservation experiment showed that the optimal addition amount of sodium propionate and ?-polylysine hydrochloride were 0.20%and 0.004%,respectively,and the optimum concentration of citric acid leaching concentration was 1.5%.After storage for one month at room temperature at 25?,the sensory score and the total number of colonies were used as indicators.On the basis of the single factor preservation experiment,the preservation effect of the three preservatives was optimized by orthogonal experiment.It is known from the experimental results.The best preservation combination was 0.20%and 0.004%for sodium propionate and ?-polylysine hydrochloride,respectively,and Soaking in 1.5%citric acid solution for 2 min.(3)Study on storage and shelf life of fresh wet yuba.The fresh wet yuba for the best preservation method(add 0.20%sodium propionate,0.004%?-polylysine hydrochloride and 0.20%citric acid compound preservative,combined with Soaking in 1.5%citric acid solution for 2 min,vacuum packaging and 85? water bath for 30 min)was stored at 35?,25? and 4?.The total number of colonies,texture,color difference,water activity and sensory evaluation were used as indicators to observe the change of quality characteristics of fresh wet yuba in the best preservation group at different storage temperatures.The experimental results showed that the fresh wet yuba treated with the best preservation method was stored at 35? 25? and 4? for about 32 d?52 d and 73 d,respectively,ano from the change of the characteristics of each index of the sample,the optimal storage temperature to ensure the sensory stability of the sample is 4?;at the same time,the above-mentioned fresh-keeping treatment method is tested for factory production.Under the storage conditions of 35?,25? and 4?,the storage period was about 23 d?41 d and 67 d,respectively.(4)Qualitative identification of spoilage bacteria in fresh wet yuba.Through microbial morphology observation,physiological and biochemical test and molecular biological identification,there are mainly 2 strains of bacteria for fresh wet yuba in the best freshkeeping treatment group,which are Bacillus coagulans and Staphylococcus saccharolyticus.There are 4 strains of bacteria,2 strains of yeast and 2 strains of mold for fresh wet yuba in the blank group,among which the bacteria are Citrobacter murliniae,Bacillus siamensis,Staphylococcus.Bacillus coagulans;yeast is Wickerhamomyces anomalus and RhodotoruLa mucilaginosa strain:mold is White rhizopus and Penicillium.It can be seen from the above that the fresh wet yuba of the best fresh-keeping treatment group of this subject is no longer contaminated by mold and yeast,and the bacterial richness in the product is lowered.(5)Factory design and enterprise standard formulation with an annual output of 2,000 tons of fresh wet yuba.According to the relevant requirements,the plant layout plan was designed;according to the production process,the layout plan of the production workshop with an annual output of 2,000 tons of fresh wet yuba and the production process flow chart of the equipment were determined;the production equipment and model were determined according to the process flow and annual production requirements;According to the technical and economic analysis,at the initial stage of construction,the fixed assets investment was about 9.4 million yuan,the annual current assets investment was about 17.3746 million yuan,and the annual sales was about 24 million yuan.According to the annual output of production enterprises and the statutory working hours,the employees work 250 days a year,work 8 hours a day and 3 shifts a day.The annual water consumption is estimated to be 11600 tons,and the annual electricity consumption is estimated to be 325225 kw·h.At the same time,according to the actual production process and related requirements of the factory,a set of fresh wet yuba production enterprise standard was formulated.