Probiotic Activity Of Polysaccharides From Longan,goji And Jujube And Development Of Nutritional Meal Powder

Longan(Dimocarpus longan Lour.),goji(Lycium barbarum Mill.)and jujube(Zizyphus jujube Mill.)were all typical edible and medicinal plants,whose fruit ripened with strong seasonality and were not durable for storage.At present,they were mainly processed and sold in dry.Polysaccharides were the main active substances in longan,goji and jujube,which had immunomodulatory,antioxidant and probiotic activities.In order to promote the deep processing of longan,goji and jujube and increase their added value,the physicochemical properties and probiotic activities of longan polysaccharide,goji polysaccharide and jujube polysaccharide were investigated using dried fruits as raw materials,and the probiotic ratio was optimized.Furthermore,longan,goji and jujube were used as raw materials to develop a kind of nutritious meal powder with beneficial health function.The main research results and conclusions are as follows:(1)Physical and chemical properties and probiotic activities of longan polysaccharide,Lycium barbarum polysaccharide and jujube polysaccharideLongan polysaccharide(LP),goji polysaccharide(GP)and jujube polysaccharide(JP)were prepared by water extraction and alcohol precipitation,the basic composition,molecular weight distribution,monosaccharide composition,functional group composition,microstructure,solubility,particle size and solution potential of the three polysaccharides were analyzed,the results showed that the three polysaccharides mainly contained neutral sugar,uronic acid and a small amount of protein.The MW of LP and JP were 70.73 and185.93 ku,respectively,while the MW of GP was 120.61 and 4.53 ku.LP and GP were mainly composed of arabinose,glucose and galactose,with the molar ratio of22.49:56.81:10.18 and 16.84:62.05:11.08,respectively.JP was mainly composed of arabinose,glucose and galacturonic acid,with the molar ratio of 10.63.70.05,10.88.Three polysaccharides contained typical functional groups of polysaccharide structure characteristics,and all of them are acidic polysaccharides.The microstructure of the three kinds of polysaccharides were different.LP was a fragmented aggregate,GP was lamellar,JP was reticular.There was no significant difference in the solubility of the three polysaccharides,and their particle size was JP>LP>GP,the particle size dispersion index was GP>LP>JP,absolute potential was JP>LP>GP.In the concentration range of 1-30 mg/m L,the three polysaccharides could significantly promote probiotics proliferation,and showed a dose-dependent effect.At the highest concentration,the probiotics of the three polysaccharides were JP >GP >LP.LP,GP and JP at the mass ratio of 2:3:1,the probiotic activity of complex polysaccharides was the strongest and significantly stronger than that of the three polysaccharides at the same concentration.The results showed that the compound of longan,goji and jujube had synergistic effect on probiotics.(2)Research and development of longan-goji-jujube nutritional meal powderBased on the optimized probiotic ratio of LP,GP and JP, the weight ratio of dried longan,dried goji and dried jujube powder was determined to be 3.59:4.66:1.Orthogonal test was used to optimize the process of compound fruit powder as follows: whey protein as auxiliary material,the mass ratio of raw material to auxiliary material was 1:1.5,freezing ultrafine grinding time of 150 s,under these parameters,the sieving rate of compound fruit powder was 91.24%,the moisture absorption rate was 5.01%.The nutritious meal powder was developed on the basis of the compound fruit powder,the optimum proportion of longan-goji-jujube nutritional meal powder was determined by mixture design as follows: 50% compound fruit powder,30% maltodextrin powder,10%rice puffed powder,5% whole milk powder and 5% plant fat powder,the longan-goji-jujube nutritional meal powder obtained by this formula has good stability,good sense and balanced nutrition.The contents of carbohydrate 60.1 g/100 g,protein 25.3 g/100 g,fat 5.8 g/100 g,water 6.75 g/100 g,Ash 2.1 g/100 g,sodium 101mg/100 g,energy 1666 k J/100 g were determined,the content of functional factor polysaccharide is 1.5 g/100 g.The probiotics of longan-goji-jujube nutritional meal powder were studied by in vitro fermentation model.It was found that longan-goji-jujube nutritional meal powder could promote the growth of intestinal flora.The physical and chemical properties of LP,GP and JP were significantly different,and they had synergistic life.Based on this synergistic effect,the development of compound nutritional meal powder for longan,goji and jujubes is guided,and the relevant research results could provide references for the deep processing of longan,goji and jujube and the development of nutritional functional products.