Study On The Nutrition And Functional Properties Of The Polypeptide Of The Walnut Juglans Comes Dali,Yunnan

Walnut with a variety of health benefits is one of our common edible nuts. So far, there has little research on the deep processing walnut and its byproducts in China, in the other hand, there has a lot of research on the enzymatic treatment on walnut by using the enzyme proteins, however, no studies for Juglans sigillata which are our geographical indications come from Dali, Yunnan.In this study, Juglans sigillata has been studied firstly, including determination of basic nutrients of Juglans sigillata, preparation of Juglans sigillata polypeptide and their biological activities of peptide hydrolysis, thus obtained the following conclusions:Firstly, the conventional nutrients of Juglans sigillata were determined and compared with other varieties of walnuts, the results showed that walnut Juglans have higher nutrient content. It can be used as functional food ingredients, and can be providing important evidence for the subsequent researchers.Secondly, Six kinds of proteolytic enzymes were investigated hydrolysis by degree of hydrolysis and protein recovery, the results showed that alkaline protease hydrolysis has better results, then, alkaline protease hydrolysis conditions were optimized by orthogonal test including the single factor test of hydrolysis temperature, pH, enzyme concentration and solid-liquid ratio. In the last, the best conditions of alkaline hydrolysis walnut Juglans protein were obtained which were reaction temperature60℃, solid-liquid ratio1:30, pH values of9.5and the amount of enzyme was7%, under this condition, the degree of hydrolysis walnut Juglans protein was19.2%.The relevant physical properties of the hydrolysis of peptide walnut Juglans were measured, the hydrolysis of peptide walnut Juglans were further purified by using ultrafiltration, macroporous resin and gel chromatography, and the ACE inhibition and antioxidant activity was determined. The results show that:fraction1molecular weight less than1kDa obtained by ultrafiltration whose polypeptide ACE inhibitory activity than the original hydrolysis liquid, reaching75.37%, then its ACE inhibitory activity reached79.93%by desalted using macroporous resin, on this basis, the ACE inhibitory rate of component P2reached82.79%after separation by gel chromatography; on the other hand, fraction1molecular weight less than1kDa and fraction2Molecular weight greater than1kDa and less than5kDa obtained by ultrafiltration whose polypeptide antioxidant activity than the original hydrolysis liquid, reaching68.89%and66.61%, respectively, then its antioxidant activity reached70.19%and71.06%by desalted using macroporous resin, on this basis, the antioxidant activity of component P5and P7reached75.42%and77.28%after separation by gel chromatography.The results fully illustrate the peptide hydrolysis Juglans sigillata with high ACE inhibitory and antioxidant activity can be purified and isolated effectively by using of ultrafiltration, macroporous resin and gel chromatography.