Study On The Preparation Of Longan-Oat Nutritional Meal Powder And Its Regulation On Intestinal Flora

The acreage and production of Longan of China rank first in the world.Longan pulp is rich in polysaccharides,polyphenols and other active ingredients.It has the functions of enhancing immunity and improving memory.But longan processing products in China are less than 30% of the total output,and the main products are drying longan products,with a single product form and low processing level.Therefore,the development of longan products with high added value can make full use of the medicine-food of longan,improve the processing utilization of longan,and provide scientific guidance for the deep processing of longan.In this paper,using fresh longan as raw material,The effects of different pretreatment methods on the nutritional quality and application characteristics of dried longan were compared,The grinding process of longan dried fruit was built at normal temperature.The longan-oat nutritive meal power with intestinal microflora regulation was developed,and its functional activity was evaluated through animal experiments.The main methods,results and conclusions in this study are presented as follows: 1.Effects of different pretreatment methods on nutrition quality and application characteristics of dried longanHeat pump drying,ultrasonic pretreatment,microwave pretreatment,NaCl impregnation pretreatment,hot blanching pretreatment and freeze thawing pretreatment were ued to obtain dried longan pulp.Different pretreatments had a great impact on longan quality.Hot blanching and freezing thawing reduced the water content of the dried longan and increased the hardness of the dried longan,especially the effect of hot blanching was remarkable.Ultrasonic,microwave and hot blanching reduced the browning degree of longan dry,and the color of microwave and hot blanching were better.In nutrition,compared with fresh longan,drying process lost a part of polysaccharides,polyphenols and flavonoids,and reduced ORAC activity.Compared with unpretreatment,impregnation and freezing thawing reduced the polysaccharide extraction rate of longan dry and freezing thawing reduced the polysaccharide content of longan dry,and there was no significant difference in other pretreatment.Ultrasonic and microwave could improve the content of phenol,total phenol content and ORAC activity.In the midstream of longan,In addition to NaCl impregnation,there was no significant difference in other five kinds of pretreatment.The main flavor substances of longan were alkenes and alcohols,and the high content flavors were alenene,3,7-two methyl-1,6-ocdiene-3-alcohol,ethanol and so on.Compared with the unpretreatment,pretreatment of the dried longan meal improved the flushing of meal by reducing disperse time,but it could't improve the fluidity of meal.In addition,impregnation,hot blanching and freeze thawing reduced the moisture absorption rate of meal and prolonged the shelf life of meal powder.2.Study on the grinding process of longan at normal temperatureThrough the mixture design,the optimum ratio of raw materials was as follows: 60% of longan,20% of oat powder,10% of soybean powder and 20% of rice flour.Under this formula,the 4 min was crushed,the screening rate(20 mesh)was 93.46%,the WSI of longan powder was 57.15%,WAI was 2.21,the dispersing time was 40.13 s,and the sensory score was 81.19 score.In longan powder,yam and maltodextrin were added to prepared longan-oat nutritional meal powder.The water content was 5.07%,carbohydrate content was 76.12%,protein content was 12.26%,fat content was 4.96%,ash content was 1.59%,and the content of crude polysaccharide as functional factor was 310mg/g.3.Effect and mechanism of longan-oat nutritional meal powder on regulating intestinal floraMice were randomly divided into control group,positive control group,longan oat group and low,medium and high doses of meal powder group for 30 d.The results showed that compared with the control group,The number of Bifidobacteria and Lactobacillus increased significantly in teams(P < 0.05).The number of Enterococcus,Enterobacteria and Clostridium perfringens decreased in varying degrees in teams.According to the Health Food Specification(2003),longan oat and nutritional meal powder regulated intestinal flora and high dose nutritient power was similar to longan oat group,which was better than positive control group,indicates that the longan oat was the material basis for the meal meal to play the intestinal improvement.Compared with CT,the content of SCFA in intestinal microflora of each team increased significantly(P < 0.05).It showed that nutritient power increased the diversity and abundance of intestinal flora by 16 SrDNA analysis.In addition,compared with control group,the medium and high dosage of meal powder increased the thymus index in mice,and the content of total protein and albumin in the serum of mice.The content of IgG,IgM and S-IgA of every team could be increased in different degrees.At the same time,the content of IgE and IgA could be significantly increased in high dosage of meal powder group.On the cytokine,the longan oats led to the increase of IL-2,and the content of IL-4,INF-? and TNF-? decreased.Three meal dosage teams decreased of IL-1,IL-5,INF-? and TNF-?,but high dose nutritient power increased the level of IL-2 and IL-6,suggesting that meal powder had a certain immunomodulatory function.It was inferred that the polysaccharide and other substances in the meal was hydrolyzed into organic acids in the intestinal tract,which promoted the proliferation of beneficial bacteria and inhibits the growth of harmful bacteria,and increased the diversity and abundance of the bacteria.In addition,the bacteria improved the secretion level of immunoglobulin,cytokines stimulate differentiation,thereby strengthening the immune function.