Study On The Preparation Of A Novel Mulberry Powder And Its Effect On Improving Gastrointestinal Tracts

In this study,a novel mulberry powder was prepared from fresh mulberries through the following steps:drying by vacuum microwave,extruding by twin-screw extruder,and finally smashing by superfine grinding.Then,the effect of obtained powder on the gastrointestinal function,and its action mechanism were investigated.The research contents and results are as follows:?1?Preparation of the novel mulberry powder Firstly,the fresh mulberry was used as the raw material and dried by vacuum microwave.The influences of microwave power and the thickness of loaded material on the mulberry's drying characteristic curve,the bio-activity and physicochemical indexes of obtained product were studied,and the optimized conditions were:power 3kW,thickness 30 mm.Then,the dried mulberry was extruded by twin-screw extruder.The optimal conditions were:the ratio of mulberry and soybean was 4:1,puffing temperature was 120 ^oC,and screw speed was 200 r/min.Finally,the mulberry was smashed by superfine grinding.Under the optimal conditions,the mulberry powder with a size of 3.08?m and bulk weight of 0.913 g/mLwas obtained.The total anthocyanin and DNJ content of obtained powder were 215.3 mg/100 g and 43.7mg/100 g.Its water-absorption,oil-absorption capability and antioxidant ability were also determined,the results was 0.879 g/g,2.9 m L/g and 32.7?molTE/100 g,respectively.?2?Characterization of obtained powder on the gastrointestinal function Compound diphenoxylate was used to induce constipation in KM male mice,and phenolphthalein tablet was taken as positive drug to treat constipation.Randomly divided 60 KM male mice into normal control group?NC?,constipation model group?CM?,positive control group?PC?,high dose group of mulberry powder?HE?,middle dose group of mulberry powder?ME?,low dose of group mulberry powder?LE?.HE,ME and LE group respectively fed with 0.2 mL/?10 g·bw?mulberry powder solution by gavage for 250,125 and 62.5 mg/mL.NC and MC were given with equal volume physiological saline,PC was fed with equal volume of 5 mg/mL phenolphthalein tablet soulation.After 15 d administration,PC,MC and the experimental groups were treated with compound diphenoxylate,NC with physiological saline.Then,the propulsion rate of small intestine,the discharge time of first red stool,the number of discharge stool and the moisture content of feces in the 6 h were measured.The results showed that the mulberry powder can significantly improve the propulsion rate of small intestine?P<0.05?,shorten the discharge time of first red stool?P<0.05?,increase the discharge number and weight of the red stool in 6 h?P<0.05?,improve the water content of feces?P<0.05?,reduce the residual rate of gastric contents?P<0.05?.In conclusion,obtained mulberry powder had significant effect on improving the gastrointestinal function.?3?Action mechanism of obtained powder on the gastrointestinal function The group design and mouse feeding followed as before.From the beginning of16 d,5 consecutive days of PC,MC and the experimental groups were treated with compounddiphenoxylatesoulation?10mg/?kg·bw??,andtogetherwith phenolphthalein tablet soulation,physiological saline,the corresponding dose mulberry powder soutation,respectively.NC was given with physiological saline.Next 2 days,MC and NC,PC,experimental groups were respectively given by gavage with physiological saline,phenolphthalein tablet soulation,mulberry powder soutation.After that,serum,small intestine,colon and faeces from colon were collected.Gastrointestinal hormones,neurotransmitters indicators and the activity of antioxidant enzymes in serum and colon,and the contents of short chain fatty acids in faeces were measured.The expression level of aquaporin genes were analysized by Q-PCR.Histopathological observation showed that gavage mulberry powder can significantly increase the number of mucous cells in colon tissue.Gavage of mulberry could significantly improve the content of acetylcholine?Ach?,and reduce the content nitric oxide and MAD,could also improve the oxidative damage by increasing the activity of superoxide dismutase?SOD?,catalase-peroxidase?CAT?,glutathione peroxidase?GSH-Px?in serum and colon of rats?P<0.05?.In addition,intake of mulberry powder could significantly improve the content of motilin?MTL?and substance P?SP?,and reduce the levels in serum?P<0.05?of constipation mice.At the same time,the expression of aquaporin?AQP₃,AQP₄,AQP₈,AQP₉?in colon and the content of short chain fatty acid in faeces were significantly reduced?P<0.05?in experimental groups.The results suggested that mulberry powder could improve constipation by increasing the levels of enteric neurotransmitters,gastrointestinal hormones,enhancing the antioxidant capacity of colon,and decreasing the expression of colon aquaporin gene.