Optimization Of Extraction Process,Structural Characterization And Functional Characteristics Of Polysaccharide From Seeds Of Millettia Dielsiana Harms

As an agricultural product with a long edible history,rock beans have not been well used,and there are few reports of research in the field of food.In order to provide a certain data reference for the development and utilization of rock beans and increase the added value of rock beans,this paper uses degreasing rock bean flour as raw material to extract rock bean polysaccharides from rock bean degreasing powder by hot water extraction.The preliminary structural characterization of rock bean polysaccharide was carried out,and the antioxidant activity of rock bean polysaccharide and the processing characteristics of rock bean polysaccharide were studied,providing a certain reference for the development and utilization of rock bean.The main research results are as follows:(1)The effects of different factors on the yield of polysaccharides were investigated.With the increase of solid-liquid ratio,temperature and time,the extraction of polysaccharides increased firstly and then decreased,and reached the highest at the solid-liquid ratio of 1:45,temperature of 85 ℃ and time of 45 min;based on single-factor experiments,the better extraction process of PMHS is 1:46,tempera ture 83 °C,and time is 47 min by optimizing the response surface.Under this condition,th e extraction rate is 12.77 %±0.07 %.(2)The primary structure of PMHS is analyzed,and the research results are as follows.The molecular weight of PMHS is mainly distributed in the three intervals: 57.5k Da~95.0 k Da,995.0 k Da~250.0 k Da and 250.0 k Da~558.4 k Da.The percentage content of each interval is 64.0%,27.9% and 9.1 %.PMHS is composed of manna,mouse plum glucose,gluconylic acid,galactose,glucose,galactose,xylose,Arabianose and rock halose,of which mannose,glucose and galactose account for the highest proportion,with a total molar percentage of 82.08 %.(3)The effect of in vitro digestion on the antioxidant activity of PMHS.The results show that after simulating gastric digestion,the antioxidant activity of PMHS increases,while intestinal digestion has obvious adverse effects on the antioxidant properties of PMHS.During gastric digestion treatment for 1 h,the scavenging effect of PMHS on hydroxyl radicals reaches the best level,with a scavenging rate of about 22%;after gastric digestion treatment for 4 hours,the total reduction force is significantly enhanced;and the scavenging rate of PMHS for DPPH free radicals after gastric digestion has increased significantly,increasing by about 6%.(4)The foaming properties and foam stability of PMHS are higher than those of market whey protein.When the p H value is 7,the foaming and foam stability of PMHS are the best;the effect of glucose and Na Cl on the foaming of PMHS is not significant;but it has a significant positive impact on the foam stability of PMHS.Compared with the market whey protein,the emulsification of PMHS is significantly weak,and the emulsification stability is significantly stronger.With the increase of p H,the emulsification of PMHS shows an increasing trend,and the emulsification stability reaches the highest when p H is equal to 7;glucose has no significant effect on the emulsification and emulsification stability of PMHS;the effect of Na Cl on emulsification is not very obvious,while high concentrations of Na Cl on the emulsion of PMHS.Chemical stability has obvious adverse effects.