Screening and Identification of Excellent Lactic Acid Bacteria from Chopped Pepper in Hunan and the Flavor of Fermented Pepper Juice

Taking the natural fermentation chopped pepper in Hunan as the research object,the high-yield lactic acid bacteria were isolated and screened,and identified by morphological observation and 16s rDNA. Through the study of biological characteristics such as growth curve,acid tolerance and salt tolerance,excellent lactic acid bacteria strains were obtained,and the number of lactic acid bacteria,pH and flavor volatile components in the process of fermenting pepper juice were compared. The results showed that three high acid-producing strains BLHN3,EJT2 and PDJ1 were identified as Lactobacillus fermentans,and PDJ1 had the strongest tolerance to stress. During the fermentation of pepper juice,the number of lactic acid bacteria increased,pH decreased gradually,and the pH of fermentation broth of strain PDJ1 was the lowest. The comparison of volatile components in fermented pepper juice by solid phase microextraction-gas chromatography-mass spectrometry was BLHN3(37 species)>PDJ1(34 species)>EJT2(28 species). The relative contents of linoleic acid ethyl ester,ethyl acetate and ethyl octanoate were the highest. PDJ1 produces the highest relative content of special aroma substances such as(E)-2-hexene-1-ol and geraniol,which gave pepper juice fruit aroma and fragrance. The flavor of chili juice fermented by strains BLHN3 and PDJ1 was more prominent than that of strain EJT2.