Study On Blanching, Superfine Grinding Of Water Dropwort And Processing Technology Of Solid Beverage With Hypoglycemic Activity

In this study,water dropwort(Oenanthe javanica DC.)was used as raw material.Firstly,the effects of hot water and microwave blanching on the quality and sensory characterstics were researched.Secondly,the effect of superfine grinding on the physicochemical properties of water dropwort powders was analyzed.Then,the hypoglycemic effect of water dropwort aqueous extract(WDAE)was investigated.Finally,the processing technology of water dropwort soild beverage was studied.The main contents and results were as follows:1.The effects of hot water and microwave blanching on the quality and sensory characteristics of water dropwort were reserached.The changes of the residual polyphenol oxidase activity,weight loss,phytochemicals,color,firmness,flavor and sensory evaluation were investigated.The artificial neural network model was used to analyze the sensory preference and optimize the blanching conditions.The results showed that high heating intensity could inactivate the polyphenol oxidase activity,enhance the brightness and greenness,but destroy the texture of water dropwort both in hot water and microwave blanching.Meanwhile,microwave blanching could reduce the weight loss and retain more nutrients,and hot water blanching was conductive to reducing the unpleasant flavor.After prediction of artificial neural model,water dropwort treated with microwave blanching at 600 W for 1 min had the highest sensory acceptability.Objective color and taste parameters were the most significant factors affecting the sensory preference,and the objective color and taste parameters obtained by the microwave blanching of 600 W for 1min could be recommended as an important reference for the actual production of water dropwort.Hence,microwave blanching could be a good alternative to hot water blanching.2.The effect of superfine grinding on physicochemical properties of water dropwort powders was invesigated.The powders of four particle sizes were obtained by coarse and superfine grindings,respectively.The changes of the particle size distribution,main chemical composition,color,main chemical components,thermal,functional,dissolution and dispersion properties were analyzed.The results showed that the superfine grinding could increase the brightness and greenness of the powders.After superfine grinding,the solubility,water holding and swelling capacity,as well as thermal stability increased significantly.In addition,the dissolution rate of flavonoids,total phenols,soluble proteins and polysaccharides in water dropwort increased greatly after superfine grinding,so as to improve the bioavailability of superfine grinding powders.Compared with the course powders,the superfine grinding powders(< 38 μm)showed better dispersibility in colloid solution,especially in xanthan gum solution.3.The hypoglycemic effects of WDAE on streptozotocin-induced diabetic mice were investigated.The hyperglycemia model was induced by the injection of streptozotocin in Kunming mice,following by administrating with high,medium and low doses of water dropwort extract for 4 weeks.The hypoglycemic activity of the mice was analyzed by measuring body weight,food intake,blood glucose,organ index,oral glucose tolerance,insulin tolerance,and antioxidant enzymes activity in vivo.The hypoglycemic signaling pathway was analyzed by Western-blot.The results showed that high dose of WDAE(400 mg/kg/d)could significantly reduce fasting blood glucose and serum insulin levels,and improve glucose and insulin intolerance in diabetic mice.Meanwhlie,the extract could improve the insulin resistance,insulin sensitivity and damage of pancreatic β cells of hyperglycemic mice.In addition,the extract was beneficial for increasing the antioxidant enzymes activities in the serum and liver of mice,as well as reducing the level of lipid peroxidation.Western-blot analysis demonstrated that the extract could alleviate the insulin resistance through the IRS-2/PI3K-Akt and GLUT-4 signaling pathways.4.The analysis of chemical composition in WDAE was conducted.The results showed that the water dropwort extract was abundant with polysaccharide,flavonoids and total phenols.LC-MS/MS analysis identified that there were five kinds of phenolic acids,ten types of flavonoids and its derivatives including caffeic acid,chlorogenic acid,p-coumaric acid,isochlorogenic acid A and isochlorogenic acid B;quercetin,rutin,and hyperoside,kaempferol-3-O-rutinoside,astragalin,isorhamnetin,isorhamnetin-3-O-neohesperidin,narcisin,luteolin and apigenin in the extract.5.The processing technology of water dropwort solid beverage was also studied.The effects of different proportion of konjac powders on the rheological properties and stability of the solid beverage were reserached.Then,the ratio of different raw materials was optimized in single factor and orthogonal tests in turn.The results showed that adding konjac powder could increase the viscosity,water holding and swelling capacities,as well as the stability of the solid beverage.The optimal ratio of water dropwort to konjac was 4:1.After optimization,the optimal formula was water dropwort powder 42.0%,konjac powder 10.5%,oligofructose 21.0%,maltodextrin 26.2%,and xanthan gum 0.3%.This beverage was popular with the rich nutrition,fragrant flavor,bright color and excellent taste.