Study On The Technology Of Nata De Coco Fermented Liquid Recycling

Now, Hainan Province has become a major bases for nata de coco producing. But in recent years, as the huge importing of nata de coco, the nata processing enterprises were adversely affected in Hainan Province. Many enterprises in order to save production costs and raise efficiency of raw materials utilization, they recycling used of residual fermentation liquid from nata into new fermentation. However, such operations was been done by experience lacking of theoretical basis, it was evident influence on entire nata de coco production. In this paper, in order to develop a technology of recycling utilization of nata fermentation liquid, the changes in antioxidant activity of nata de coco culture medium before and after fermentation were also compared, and the effects of recycling utilization of nata fermentation liquid on antioxidative system and cellulose synthase activity of fermentatidn stain were studied. Based on this, a multiplex additive was designed and optimized, the affects of recycling utilization of nata fermentation liquid on nata production was avoided.The antioxidant potential of fresh and fermented nata de coco culture medium extracts were studied by using peroxidation of phospholipids liposomes assay, DPPH radical and hydroxyl radical scavenging activity, metal chelating activity, and ferric reducing power with BHT, gallic acid as standards. The results indicated that the fresh nata de coco culture medium extract had a higher peroxidation of phospholipids liposomes inhibiting activity, DPPH radical and hydroxyl radical scavenging activity, ferric reducing power and metal chelating activity than fermented nata de coco culture medium extracts. The results proved that the antioxidant activity of fermented nata de coco culture medium was also decreased significantly, as well as the oxidative damage protection ability of fermentation strain.The antioxidation ability and cellulose synthase activity of two kinds of Gluconacetobacter xylinum cell extracts were studied by using the total antioxidant capacity assay, the peroxidation of phospholipids liposomes degree assay, the SOD activity and cellulose synthase activity assay. Before those assays, the cell extracts had been extracted from normal fermentation liquid and waste nata de coco fermentation liquid, respectively, by centrifugation and ultrasonic disruption. The results showed that the waste nata de coco fermentation liquid group has a higher total antioxidation capacity, the SOD activity, the cellulose synthase activity and the degree of peroxidation of phospholipids liposomes than normal cultivated group.To solve the problem about the effects of recycling utilization of nata fermentation liquid on fermentation strain, one antioxidant and two metabolic regulated additives were selected and remixed based on all above results and theory of metabolic regulation. The formula was optimized through single-factor tests and response surface experiment. The result showed that the optimum additive formula was Vc 0.014%, UDP-Glucose 0.0049%, Na2SO3 0.0208%. The nata de coco production was increased by one time and 64% when Gluconacetobacter xylinum was cultivated under the optimal formula as compared with the not using additive group and normal cultivated group, respectively.Through analyzing the changes in antioxidant activity of nata de coco culture medium before and after fermentation and the effects of recycling utilization of nata fermentation liquid on antioxidative system and cellulose synthase activity of fermentation stain, the paper further confirms that the main causes of effect nata yield was the oxidative stress of the antioxidation reduced on fermentation strain. For the above reasons, a complex quality improver was developed. This project’s researches provide a scientific research basis for the recycling utilization of nata fermentation liquid.