Comparative Study On Functional Properties And Structure Of Soluble Soybean Polysaccharides From Different Sources

Okara,residue after extracting soybean protein(RAESP)and soybean hull(SBH)are the most common by-products from soybean making.Okara,RAESP and SBH are rich in soluble soybean polysaccharides(SSPS).Domestic research on SSPS are mainly focusing on extracting SSPS from Okara,while there are few research and reports on the development of SSPS products extracted from RAESP and SBH,and there was no comparative study on SSPS from three sources.In this study,soluble soybean polysaccharides(SSPS I)from Okara,soluble soybean polysaccharides(SSPS II)from RAESP and soluble soybean polysaccharides(SSPS III)from SBH were extracted.The functional properties and structures of SSPS from three sources were compared and analyzed,as well as the functional properties and structures of SSPS with different molecular weights from the same source.The relationship between structure and functional properties of SSPS was preliminarily verified.The main contents and results of the study are as follows:(1)Comparative Study on Functional Properties and Structures of SSPS from Different Sources The functional properties and structures of SSPS from three sources obtained by hot water extraction were analyzed.The results showed that SSPS Ⅰ which extracted from Okara had the best antioxidant activity,emulsifying properties and foaming properties among three kinds of polysaccharides,followed by SSPS Ⅲ extracted from SBH,then SSPS Ⅱ extracted from RAESP.The results of HPLC and FTIR analysis showed that there was no significant difference in the structure of SSPS.(2)Comparative Study on Functional Properties and Structures of Different Molecular Weight SSPS from the Same Source SSPS from the same source were separated by ultrafiltration.The functional properties and structure of SSPS with different molecular weights after ultrafiltration were analyzed.The results of HPLC and FTIR indicated that the ultrafiltration has successfully separated the SSPS with different molecular weights.In terms of emulsifying properties and foaming properties,high molecular weight SSPS are better than low molecular weight SSPS;and in the terms of antioxidant activity,the low molecular weight SSPS perform better than the high molecular weight ones.(3)Comparative Study on Emulsifying Properties and Foaming Properties of High Molecular Weight SSPS from Different Sources In emulsifying activity,SSPS II-H had the best emulsifying activity,followed by SSPS I-H,then SSPS III-H.In emulsifying stability,SSPS I-H had the best emulsifying stability,followed by SSPS III-H,then SSPS II-H.According to the results of emulsifying activity and emulsifying stability,SSPS I-H had the best emulsifying properties,however,the differences in emulsifying properties among highmolecular weight SSPS from three sources are not significant.In terms of foaming properties,the order of foaming capacity of three high molecular weight SSPS was SSPS III-H >SSPS II-H >SSPS I-H,and the order of foaming stability of three high molecular weight was SSPS I-H >SSPS II-H >SSPS III.(4)Comparative Study on Antioxidant Activity of Low Molecular Weight SSPS from Different Sources Antioxidant activity analysis of low molecular weight SSPS from different sources was carried out by using DPPH scavenging rate,hydroxyl radical scavenging rate and reducing power.In combination with the three indicators,SSPSIII-L has the strongest antioxidant activity,followed by SSPSI-L,and SSPSII-L has the weakest antioxidant activity.