Study On Changes Of Microflora In Naturally Fermented Coconut Water Used In Nata De Coco Production

Coconut water (CW) is an important raw material for production of Nata de coco in Hainan area. At present, the manufacturers produce Nata de coco by usually using coconut water of static natural fermentation for5-6days as medium, because its yield is relatively higher than that by using fresh coconut water as medium, but the specific reasons still are unclear. In which microbes is the key to caused difference of two kinds of culture media. The changes of microflora in the coconut water during natural fermentation have not yet been reported in the literature. Therefore, this paper explores the microflora and its change in the coconut water during natural fermentation by using high-throughput sequencing (HTS) and traditional culture methods at the laboratory in Haikou and the factory in Wenchang, and compares the difference of two kinds of identification methods. At the same time, it carries out the general composition analysis to understand the relationship between the bacteria and the change of composition.The main results are as follows:(1)The dominant groups of microorganisms in the samples from the laboratory and factory change along with the passage of the natural fermentation time: At the beginning, the dominant populations and fermentation are the alcohol fermentation and the lactic acid fermentation. From the fourth day, the acetic fermentation rises. However, from the sixth day, the alcohol fermentation decreases, at this time, the lactic acid fermentation and the acetic fermentation stay in the dominant position.(2)The dominant strains of yeast are basically the same.But lactic acid fermentation are different under the conditions of the laboratory and factory. Lactic acid fermentation gives priority to Lactobacillus (accounts for about50%of the total bacterial count) under condition of the laboratory, the dominant strains are Lactobacillus brevis and Lactobacillus zeae.Lactic acid fermentation gives priority to Leuconostoc sp (accounts for about50%of the total bacterial count) under condition of the factory, the dominant strain is Leuconostoc mesenteroides.(3)Proportion of Acetobacter bacteria accounts for the total bacterial count (0.25%?5.06%) under condition of the laboratory is more than that (<0.5%) under condition of the factory, and Acetobacter sicerae, Acetobacter tropicalis are dominant strains.(4)Microbial species and quantity in natural fermented coconut water in factory were higher than that in laboratory samples. These bacteria are a lot of lactic acid bacteria and acetic acid bacteria, their characteristics, function and application in Nata de coco production need further study. It is the result of the cooperation fermentation of different kinds of microorganisms including yeasts, lactic acid bacterium, acetic acid bacterium and bacillus that the promotion of the natural fermentation coconut water on gluconacetobacter to produce bacterial cellulose, so, on the one hand, single strain fermented coconut water could be screened by pure strain fermented coconut water experiment and could replace natural fermented coconut water. On the other hand, mixed culture fermented coconut water could be screened by cooperation of different microorganisms could replace naturally fermented coconut water; it is better than the natural fermentation coconut water in the production of Nata de coco. Then not only the production of Nata de coco could be improved, but also the quality and security could be ensured.