Preparation Of Gracilaria Oligosaccharide And The Study On The Application Of Some Fruit Fresh-keeping

The traditional gracilaria oligosaccharide preparation method needs more steps(gracilaria-polysaccharide-oligosaccharide),higher cost,and produces a lot of wastewater and other pollutants,.This experiment uses microorganism fermentation,which uses Flammeovirga sp.Wpaga001 to degrade gracilaria directly to prepare gracilaria polysaccharides,the process of which is easy to control.5 L and 30 L extended trials was carried on to find the best enzymatic hydrolysis technique.The gracilaria oligosaccharide was used in postharvest experiments of bayberry,cherry tomatoes and Guanxi pomelo,combined with the Australian edible film technology and compared with chitosan coating.The main results are show as follows:1.The experiment showed that the Flammeovirga sp.Wpaga001 strains of bacteria can ferment in the medium which only contains gracilaria and seawater and produce a high concentration of gracilaria oligosaccharide.Its best fermentation conditions by initial optimization were 5%of the inoculum size combine with 5%of the gracilaria concentration and 37? 200 rmp shake training,2.In the 5 L scale trial,the yield of gracilaria oligosaccharide could reach 2.97 g/L with batch fermentation,while,in grading fed-batch fermentation method,gracilaria oligosaccharide yield reached to 3.47 g/L,17%more than that in batch fermentation.In the 30 L scale trial,the yield of gracilaria oligosaccharide was 3.53 g/L in grading fed-batch fermentation method.3.Experiments showed that:the commodity rate of bayberry treated by gracilaria oligosaccharide was 92%after 14 days' storage at 1±1?,and 56%in the control group,and the rate of weight loss less than those in the control group,The fresh-keeping effects of gracilaria oligosaccharide were significantly better than chitosan coating.Gracilaria oligosaccharide coating increased the commodity rate of bayberry after storage,decreased the loss of Vc and nutrients in the fruit.prevented the browning of the fruit,maintained the bayberry's original flavor and quality,and prolonged its storage period and shelf life.4.Experiments showed that:the commodity rate of cherry tomato treated by gracilaria oligosaccharide was 91%after 14 days' storage at 15 ± 1?,and 64%in the control group,and the rate of weight loss less than those in the control group,The fresh-keeping effects of gracilaria oligosaccharide were better than chitosan coating.Gracilaria oligosaccharide coating increased the commodity rate of cherry tomato after storage,reduced the respiration intensity of cherry tomatoes during storage,decreased the loss of Vc in the fruit.prevented the decay,maintained the cherry tomato's original flavor and quality,and prolonged its storage period and shelf life.5.Experiments showed that:the commodity rate of Guanxi honey pomelo treated by gracilaria oligosaccharide was 94%after 120 days' storage at 6± 1?,and 67%in the control group,The fresh-keeping effects of gracilaria oligosaccharide were better than chitosan coating.Gracilaria oligosaccharide coating increased the commodity rate of Guanxi honey pomelo after storage,reduced the loss of total sugar,titrate acid,lignin,soluble solids,Vc,and respiration intensity of Guanxi honey pomelo during storage,maintained fruit hardness and eating quality of Guanxi honey pomelo after storage,and prolonged its storage period and shelf life.