Proteomic Investigation On Sweet Potato And Bioavailability Of Concentrate Juice

Sweet potato concentrate juice become more and more popular by consumers due to its rich nutrition and efficacy.It has significant importance to select raw sweet potato materials,conduct postharvest storage and evaluate the real value of concentrate juice absorbed by human body.In this research,sweet potato in Xiongxian was used to investigate the storage quality characteristics of different varieties to determine the appropriate one.On the above basis,we analyzed the expression of different proteins in different sweet potato to provide a theoretical basis for the rational selection.Then we explored the changes of storage quality and flavor compounds and effects of active ingredient bioavailability on sweet potato concentrate juice in different high oxygen condition,which could provide technical support for post-harvest storage and further improve the absorption and utilization of concentrate juice in the body.Storage quality properties of Yizi 138,Longshu 9th and red banana were studied.All the quality indicators of three sweet potato showed a downward trend during storage except the reducing suger which showed a first increased and then decreased trend.Yizi 138 maintained relatively stable moisture and starch content,but its average juice yield was only 21.51%.The overall organoleptic properties of Longshu 9th were outstanding and its soluble protein content ranks first in three,but it was unstable and fell by 20.15%during storage.However,the juice yield of red banana was siginificantly higher than another two species,and boast of lower starch content and high sugar content on the whole.Therefore red banana was suitable for processing sweet potato concentrate juice.The total protein in strawberry fruit was extracted using the improved phenol extraction combined with ammonium acetate/methanol overnight precipitation extraction method.And the protein was analyzed with high yield(1.14 mg/g FW)and excellent quality.The SDS-PAGE gel electrophoresis resulted that most of protein molecular weight were between 25-130 KDa.There were 931,744 and 791 proteins identified in variety Yizi 138,Longshu 9 and Hong xiangjiao,in which including 103 different proteins.Further analysis found eight protein group which may be related to sweet potato quality.Among them there were 3 proteins down-regulated significantly from Hong xiangjiao to Yizi 138 and Longshu 9,including calmodulin,sucrose synthase and malate dehydrogenase,while 5 proteins up-regulated,including enolase,pyruvate decarboxylase,alcohol dehydrogenase,superoxide dismutase[Cu-Zn]and heat shock protein.The biological and metabolic functions of those proteins involved substances and energy metabolism,fatty acid metabolism,redox system and protein synthesis.High oxygen treatment could maintain the quality indicators of red banana concentrate juice.The content of soluble solids and titratable acidity and sensory scores after high oxygen treatment were better than the control group.High oxygen treatment time was not directly proportional to the quality and the best was treated by 50%-100%high oxygen for 24 hours.The transmittance of concentrate juice was 84.6%,the soluble solids content was 59.3%,the titratable acid content was 0.17%after 80 days storage.Meanwhile,it maintained the best sensory quality and the most aromatic substances.The in vitro digestion experiment showed that high oxygen treatment was helpful to maintain activities of polysaccharide,vitamin C and polyphenol in concentrate juice,thus improved the bioavailability.The best treatment was also high oxygen for 24 hours.The average bioavailability of polysaccharides,vitamin C and polyphenols was 17.67%,21.94%and 22.13%respectively during storage.