Quality Deterioration Of Wet Porphyra Yezoensis Vermicelli And Factory Design Of 1500-ton Annual Production

Vermicelli is one of the traditional starch products in China,with a millennia history of processing,it is popular among consumers.However,with the acceleration of people’s pace of life and the improvement of nutrition and personalized pursuit,traditional dry vermicelli are difficult to meet the requirements of modern consumers,because of the inconvenience caused by long time soaking before cooking,and meanwhile the nutrition and flavor of traditional dry vermicelli are relatively simple;at the seam time,traditional dry vermicelli have to go through the process of drying,consuming a lot of energy.Porphyra yezoensis（P.yezoensis）is a special resource product in Jiangsu Province,rich in resources.P.yezoensis is rich in nutrients and bioactive substances,and has broad prospects for development and application.But there are many problems in the processing of P.yezoensis at present,one of which is that P.yezoensis failed to combine with the raw materials of staple food to meet the increasingly diversified consumption demand.In this study,potato starch and P.yezoensis were used as raw materials,and fresh and wet food preservation technology was used to develop the wet P.yezoensis vermicelli.Based on the study on the quality deterioration of wet P.yezoensis vermicelli,the suitable storage temperature of wet P.yezoensis vermicelli was determined.The index of quality of wet P.yezoensis vermicelli was selected and the key factors affecting quality deterioration of wet P.yezoensis vermicelli were identified.Finally,the factory design of 1500 ton of wet P.yezoensis vermicelli and relevant enterprise standards were made,which provided theoretical and practical basis for the production enterprises of wet P.yezoensis vermicelli.The main contents are as follows:According to the relationship between the addition amount of P.yezoensis and the color change of wet P.yezoensis vermicelli,the optimum addition amount of P.yezoensis was determined by sensory evaluation.The experimental results showed that when the addition amount of P.yezoensis（Water content 57%）was 3%of the total starch addition amount,the obtained wet P.yezoensis vermicelli had the highest sensory score.In addition,according to the sensory score and microbial index,the best compound fresh-keeping formula of wet P.yezoensis vermicelli was determined as follows:total starch content,0.1%sodium dehydroacetate,0.1%glacial acetic acid.During storage,the combination of water and non-aqueous substances in the wet P.yezoensis vermicelli is more and more weak,the water holding capacity of the wet P.yezoensis vermicelli is decreased,cause its quality is deteriorated.furthermore,the sensory score,water absorption,texture characteristics（hardness,elasticity,adhesive,chewability）of the wet P.yezoensis vermicelli decreased with the increase of storage time,while the cooking loss,L*,rate of rupure and the content of frozen water increased with the increase of storage time.According to the correlation analysis and principal component analysis,the hardness and b*were selected as the visual evaluation indexes of quality deterioration of wet P.yezoensis vermicelli.And it is found that the water migration and distribution in the wet P.yezoensis vermicelli is the main factor affecting its quality.Therefore,in the storage process of the wet P.yezoensis vermicelli,the reasonable regulation of the water migration and distribution can maintain its quality to a great extent.Different storage temperature has great influence on the storage quality of wet P.yezoensis vermicelli.The water content,water activity,pH,L*and a*of wet P.yezoensis vermicelli were stable at the storage temperature of 4℃.The storage temperature of 25℃had little effect on water activity,pH,water absorption,cooking loss,hardness,elasticity,adhesive,chewiness,rate of rupure,a*,b*,freezing water content and crystallinity;35℃The effect on the crystallinity and micro structure of the wet P.yezoensis vermicelli was small,but has greater impact on other indicators.According to the change of rate of rupure of wet P.yezoensis vermicelli during storage,it can be judged that the shelf life of the wet P.yezoensis vermicelli was 12 weeks and 18 weeks at 4℃ and 35℃,respectively.And the shelf life of the wet P.yezoensis vermicelli was more than 24 weeks at 25℃.According to the production technology and production demand of the wet P.yezoensis vermicelli,the graphic design of the factory area and production workshop of the wet P.yezoensis vermicelli is carried out,and the production process flow chart of the wet P.yezoensis vermicelli is drawn.At the same time,according to the material balance and technical and economic analysis to determine the total investment amount,annual expenditure amount and annual income amount of the design,and according to the market price of wet P.yezoensis vermicelli to estimate the income of the factory.At the beginning of the construction plant,it needs to invest about 9 million yuan in fixed assets,and the annual current cost is about 12.6315 million yuan.Referring to the market price,it is estimated that the annual sales of 1500 t of wet P.yezoensis vermicelli is about 22.5 million yuan,and it is estimated that the cost can be recovered and the profit can be realized in about one and a half years.Finally,according to the relevant regulations of the state,a set of enterprise standards applicable to the production of wet P.yezoensis vermicelli is formulated.