Study On The Microorganism Ecology During Fermentation And Antioxidant Property Of Xiangxi Flavor Vinegar

Xiangxi flavor vinegar (XV) is one of Chinese traditional fermented vinegars which is produced from local herb, rice and spring water with spontaneous liquid-state fermentation techniques. It has been demonstrated that XV is with antioxidant ability.In this study we investigated the development of dominant microorganism during fermentation of Xiangxi flavor vinegar and its antioxidant property by analyzing the dominant microorganism of ZhiQu (ZQ), ethanol fermentation (EF) and acetic acid fermentation (AF) samples during Xiangxi flavor vinegar fermentation with Hiseq technique. The organic acid composition (tartaric acid, lactic acid, acetic acid, pyroglutamic acid and citric acid) of 3.5% acetic acid (AA), rice vinegar (RV), Xiangxi flavor vinegar without ageing (XVWA) and Xiangxi flavor vinegar (XV) by using HPLC. The antioxidant substances contents (rutin, gallic acid, ferulic acid, p-coumaric, vanillic acid and ligustrazine), free radical scavenging property in vitro and vivo, antioxidant enzymes (GSH-PX, SOD, CAT and GCS-1 of mutant LD1171) ability and apoptosis in C.elegans were assay to determine the antioxidant properties of Xiangxi flavor vinegar.The result showed that:1. Bacterium species were homogeneous distribution of ZQ. The species became less and less from EF to AF. In EF, bacterium that has ability of anti-ethanol can accumulate and can inhibit the grown of harmful microorganism like Bacillus cereus. In AF stage, the abundance of Lactobacillus and Acetobacter were increased by 130 and 600 respectively. The species richness seqencing was ZQ> AF>EF, the degree of homogeneity was ZQ>AF>EF.2. Fungus species were more homogeneous of ZQ than EF. In EF stage, fungus that can produce ethanol accumulated. The species richness seqencing and the degree of homogeneity of ZQ were both higher than EF.3. AA and RV has simpler organic acid contents than both XVWA and XV, and almost 95% was acetic acid. The ratio between lactic acid and acetic acid of XVWA and XV was 1.7% and 58.3% respectively. It showed that XV has a softer taste than XVWA.4. None of the antioxidant was detected in AA. In comparison, four compounds were detected in RV, except rutin and p-coumaric. Generally, the concentrations of determined antioxidant compound werw high in XV and XVWA than in RV. The amounts of rutin, gallic acid, and p-coumaric were higher in XVWA, especially rutin was not detected in XV. However, ligustrazine was much higher in XV than in XVWA, showing the accumulation of ligustrazine during aging.5. DPPH, OH and O2- scavenging rates were 95.85%,97.22% and 63.33% respectively.6. ROS content in XV treated C.elegans decreased significantly compared with control group. GSH-PX, SOD, CAT abilities and expression of GCS-1 were remarkable increased in C.elegans after XV treatment. Moreover, XV can up-regulate CED-9 protein and lower CED-3 protein. These results suggested that XV is rich in antioxidants and can scavenge radical in vitro effectively. XV can inhibit apoptosis in C.elegans may by scavenging ROS and increase ability of antioxidant enzyme. Finally, it can conclude that XV possesses remarkable antioxidant ability.