Application Study Of Lactobacillus Plantarum Ss001 In Liuzhou Sour Shoots

Sour shoots are fresh bamboo shoots as raw materials fermented to make meal food,with a special sour odor and crisp taste,the current production of sour shoots still follow the traditional family fermentation method,long production time,quality is uneven,not suitable for industrial production development needs,so it is necessary to explore suitable for industrial production to improve yield and safety.At present,most of the research on sour shoots focuses on nutrients,flavor substances and microbial separation,and there are few studies on the changes of various indicators in the fermentation process of sour shoots in different fermentation methods.In this study,a strain of Lactobacillus sour shoot-derived plantarum was applied to the fermentation of sour shoots,and the sour shoots were fermented by three ways: old water fermentation,mixed fermentation and sterilization fermentation,and the 0-60 days of sour shoot fermentation broth were taken as the research object,and dinitrosalicylic acid(DNS)colorimetric method,acid-base titration,naphthalene ethylenediamine hydrochloride method,16 S r DNA high-throughput sequencing technology,high performance liquid chromatography(HPLC),headspace solid phase microextraction combined with temperament(HS-SPME-GC-MS),The physical and chemical components,microbial diversity and flavor substances of sour shoot fermentation liquid during the fermentation process of the three fermentation methods were determined,and the quality of the finished product of the three fermentation methods was compared by texture analyzer,color difference meter and sensory evaluation,aiming to provide a certain theoretical basis for the standardized production of sour shoots in Liuzhou and the improvement of the quality of sour shoots.The specific results of the study are as follows:(1)The physical and chemical components of fermentation broth during the fermentation process of sour shoots of the three fermentation methods: the content of reducing sugars in the three groups showed a trend of first increasing and then decreasing and tending to be stable,and on the 2nd-6th day,it was reduced to 0.17 mg/m L in the old water fermentation group,0.10 mg/m L in the mixed fermentation group,and 0.16 mg/m L in the sterilization group.The total acidity stabilized at a high level after a rapid increase in the early stage of fermentation,with the total acidity reaching a maximum of 4.33% in the old water fermentation group on day 10,4.27% in the mixed fermentation group on day 8,and4.42% in the sterilized fermentation group on day 6.The nitrite content in the fermentation process showed a trend of increasing first and gradually decreasing after reaching the nitrous peak,the nitrous peak appeared in the old water fermentation group,and the nitrite content in the mixed fermentation group and the sterilized fermentation group reached a peak on the 6th day,and the nitrite content was 0.98 mg/L,0.96 mg/L and 0.97 mg/L,respectively.The ripening time of sour shoots in old water fermentation,mixed fermentation and sterilization fermentation was the 10 th,8th and 6th days,respectively,and the addition of Lactobacillus plantarum effectively increased the fermentation rate of sour shoots.(2)Flavor substances in fermentation broth during the fermentation process of sour shoots: the organic acids in sour shoots were mainly lactic acid,oxalic acid and tartaric acid,and the accumulation of organic acids in the old water fermentation group,mixed fermentation group and added fermentation group reached the highest on the 14 th,10th and8 th days,respectively,at 341.49 μg/m L,318.11 μg/m L and 323.24 μg/m L,respectively.A total of 8 categories of volatile components were measured,namely esters,alcohols,acids,phenols,aldehydes,ethers,ketones and others,of which the relative content of phenolic substances was the highest,followed by alcohols,aldehydes,acids,these four types of substances dominated the volatile components,and their relative content accounted for more than 90% of the total.The main components of volatile substances measured by the electronic nose were methyls,alcohols,aldehydes and ketones,alkanes,organic sulfides,nitrogen oxides,etc.(3)Analysis of microbial diversity during sour shoot fermentation: Proteobacteria(68.79%)and Firmicutes(22.99%)predominate among phylum-level species,and the two are mutually inhibitive.The horizontal species of the genus Lactococcus(56.43%)and Lactobacillus(9.25%)have a relatively high abundant and dominate the fermentation process,and the two show a growth trend of one or the other.The fungal fermentation group(6-8 days)entered the second stage of fermentation earlier than the old water fermentation group(8-14 days),and the addition of Lactobacillus plantarum accelerated the fermentation rate of acid shoots.Compared with the old water fermentation group,the two pathogenic bacteria,Pseudomonas and Acinetobacter,were reduced by 0.51% in the old water fermentation group,and Lactobacillus plantarum had a promoting effect on the safety of acid shoots.(4)Comparison results of the quality of sour shoots under the three fermentation methods: Compared with the hardness,elasticity and chewiness of the finished sour shoots under the three fermentation methods,the hardness(51.60±2.91)and elasticity(0.68±0.22)of the added fermentation group were higher than those of the other two groups,and the chewiness(6.28±1.51)of the mixed fermentation group was better than that of the other two groups.The b values of epidermis(15.09±5.36)and cut surface(8.73±3.71)in the bacterial fermentation group were higher than those in the other two groups,and the b values of the old water fermentation group were the smallest,and the color of acid shoots was more yellow after adding Lactobacillus plantarum,but there was no significant difference in the color difference of the finished acid shoots.The sensory evaluation score was 86.3 points in the sterilized fermentation group,which was higher than that of the mixed fermentation group with 84 points and the old water fermentation group with 82 points,and the sour shoots fermented with Lactobacillus plantarum were better than the traditional fermented sour shoots in terms of taste.The results of this experiment can provide a theoretical basis and data support for the preparation of sour shoot starter culture from Lactobacillus plantarum ss001,so as to improve the fermentation rate and improve the quality of acid shoots in the industrial development of acid shoots.