Study On Improving The Quality Of Low Salt Fermented Chili Sauce Based On Miseq High-throughput Sequencing Technology

In this study,rural naturally fermented chili sauce which collected from A(Hami District),B(Yili District),C(Changji District),D(Akesu District)and E(Urumqi District)in Xinjiang province were used as raw materials for quality detection and analysis.High-throughput sequencing technology was used to analyze the differences of bacterial and fungal community structure of Natural Fermented Chili saucewhich collected from above districts,Screen out the optimal salt-tolerant strain whih suitable for the fermentation of chili sauce.The best fermentation technology of the compound strain was determined by single factor and orthogonal test,then the quality of the compound strain was tested and analyzed.The research results were as follows:(1)The water content,total acid,reducing sugar,nitrite content,amino nitrogen,salt content,biogenic amine,capsaicin substance,metal ion,organic acid,total free amino acid content and flavor substance of chili sauce of A,B,C,D and E areas were analyzed.The results were as follows:the water content was 35.00%-77.00%;pH value was 3.30-6.70;total acid content was 0.18-4.66 g/100g;content of reducing sugar was 0.59-1.92 mg/ml;nitrite was 0.05-5.39 ?g/mL;amino peptide nitrogen was 0.01-0.19 g/100g,salt content was 4.59-13.29 g/100g;total amount of biogenic amines varied in the range of 27.66-408.36 mg/kg;the change range of capsaicin was 0.04-0.13 g/kg;content of capsaicin range from 0.01-0.06 g/kg;the range of arsenic was 2.46-13.74 ?g/kg;plumbum was 8.24-36.85 ?g/kg;cadmium range from 0.84-42.40 ?g/kg;mercury was 0.09-1.09?g/kg.Lactic acid was the main organic acids,accounting for about 30.00%.The average content of total free amino acids from high to low was:D>B>E>C>A.247species of volatile components have been identified.This study revealed the quality safety of Natural Fermented Chili Sauce of different areas in Xinjiang,and provided the basis for industrial scale production.(2)By IlluminaMiseq high-throughput sequencing,1 562 species of bacteria and 396 species of fungi were identified through Operational Taxonomic Units(OTU).Among them,Streptophyta and Lactobacillus were dominant bacteria in regions A,B,C and E.Streptococcus and Enterococcus were dominant bacteria in region D.Furthermore.Pichia,Hanseniaspora,Wickerhammyces were dominant fungi in regions A,B and C.The dominant fungus in regions D and E was Aspergillus.The specific strain of region A was Torulaspora,of region C was Clonostachys,of region E was Alternaria.This paper reveals the divergence of natural fermented chili sauce's microbial community of different regions in Xinjiang,it also provides the basis for screening suitable fermented microorganisms of chili sauce.(3)Using the naturally fermented chili sauce in Xinjiang as the material,the acid-producing lactic acid bacteria were screened under anaerobic conditions by enrichment culture and calcium dissolving method;then,the acid production capacity and NaCl tolerance of the strain were determined again,those excellent strains were identified by morphological observation,physiological and biochemical tests and molecular biology techniques at last.The results showed that 7 strains of acid-producing lactic acid bacteria were obtained.Among them,3 strains have strongest acid-producing ability and greatest salt tolerance,which strains B,SS and T were all able to tolerate 7.00%NaCl.Finally,all three strains were identified as Lactobacillus plantarum.Screening of salt-tolerant strains plays an important role in improving the quality of naturally fermented chili sauce.(4)Lactic acid bacteria and Saccharomyces rouxii play important roles in the fermentation of chili sauce.The effects of the fermentation broth ratio of Lactobacillus plantarum and Saccharomyces rouxii Rubens,the amount of added salt and the amount of onion extract added on the pH,total acid and sensory score of capsicum sauce were studied by artificial inoculation.The subsequent fermentation process was optimized through orthogonal test,and the optimal conditions were determined as follows:the ratio of fermentation solution was 2:1:1,the amount of salt added was 4.00%,and the amount of onion extract was 2.50%.The fermented capsicum sauce has good taste and flavor.The sensory score is 81.90 and the total acid content is 1.404 g/100g.(5)The optimum process conditions for fermentation were used on samples No.6 and 8,then those 2 fermentative samples and natural fermented chilli sauce were used as material in order to analysed the physical and chemical indexes,biogenic amines,capsaicin substances,metal ions,organic acids,total free amino acids and flavor substances.The results showed that the compound fermentation was superior to the natural fermentation which characterized by improving the content of amino peptide nitrogen effectively and reducing the content of nitrite and food salt content.The amine content of those 2 samples are lower compared with natural fermentation sauce,but no significant difference in capsaicin,Dihydrocapsaicin and metal ion content.The content of organic acids in Natural Fermented Chili sauce was higher than the those 2 samples,but the content of essential amino acids was lower.It was found that more volatile flavor compounds were detected in the compound fermented chili sauce,which owned better overall flavor and higher nutritional value.