Analysis Of Tomato Sour Soup During Fermentation Process And Study On The Mixed Culture Fermentation Technology For Tomato Sour Soup

Tradition sour soup is,mainly using tomatoes,glutinous rice flour,salt,strong liquor,ginger and pepper as the main raw materials of natural fermentation,fermented seasoning.Sour soup tastes delicious,rich in nutrition and contains a variety of factors which can improve the function of human being body as well as metabolism and digestion.The traditional fermentation process in use at present contains the following disadvantages,like long fermentation time,instable,complicated microbial flora involved in the fermentation and lack of reliability and stability during production process,which are not conducive to industrialized production and greatly restricts the development of sour soup industry.Therefore,during the natural fermentation process of tomato sour soup,the changes of the physical and chemical indicators,and the changes of dominant bacteria were studied in-depth in order to understand the metabolic process of natural fermentation of microorganisms in tomato sour soup,the further study of the characteristics of' the natural fermented product provides evidence for the subsequent tomato sour soup fermentation using mixed bacteria.The main contents and conclusions are as followed:1.The determination of the metabolism and fermentation end of the fermentationprocess of tomato soupInsight into the changes in physical and chemical indicators of tomato sour soup fermentation process,the main physical and chemical indicators are pH,reducing sugars,amino nitrogen,nitrite etc;tomato sour soup fermentation process lactic acid bacteria and yeasts variation were studied;and the relationship between metabolic law the quantity changes of microbial during tomato sour soup fermentation process is deeply analyzed;the end of the naturally fermented tomato sour soup is determined by using fuzzy mathematics method and sensory evaluation;volatile substances within the fermented ripe tomato sour soup were analyzed by using solid phase micro extraction GC-MS technique,28 types of volatile substances were detected,among which,esters and alcohols are the characteristic features of tomato sour soup.2.Identification of Dominant Bacteria in tomato sour soupBy using the selective medium,36 lactic acid bacteria and 16 yeasts were separated from the sample,and the microscopic observation showed that the lactic acid bacteria are short rods and the yeasts are oval;by using 16S rDNA sequence analysis,well performed 4 lactic acid bacteria and two yeasts were identified and rescreened,lactic acid bacteria were three Lactobacillu splantarum,which is Lactobacillus brevis,Issatchenkia orientalis and Pichia kudriavzevii.3.Tomato sour soup mixed bacteria fermentation process optimizationThe acid-producing effects of four screened lactic acid bacteria are different from each other,among whom,M6 is the best acid producer,can be used as the well performed lactic acid to ferment tomato sour soup;and screened yeast H2 is a better producer of aroma,can be used as fermentation yeasts.Furthermore,found both of the above two bacteria growing well under the condition of tomato sour soup when conducting the verification test.By using the pH and sensory evaluation as optimization index,through single factor and orthogonal experimental designed experiments to optimize the process,combined with physical and chemical properties,determined that the fermentation time of the tomato sour soup is 72h,fermentation temperature is 25 ?,the ratio of bacteria is 1:1 and the amount of inoculum is 5%.