Composition and Total Antioxidant Activity of Proteins from Dried Longan Fruit
Alkali-so lution and acid-isolation methods were carried out to determination the isoelectric point of dried longan protein,to analyse the composition of different p I proteins from dried longan fruit,in vitro digestion of longan proteins in different p I was conducted in a simulated digestion environment and compared the total antioxidant activity of different p I protein and its digestive fluid.The results demonstrated that: the best extracting time for longan pulp static leaching was two hours; p H3.0,p H3.5,p H4.0,p H4.5,p H5.0 were the isoelectric points of dried longan fruit proteins,and the relative percentages of longan proteins in p I3.0,p I4.0,p I5.0component from total dried longan fruit protein was 12.69%,21.68% and 17.12% respectively,all including 16 amino acids with seven essential amino acids; Proteins and its digestive fluid in different p I had different total antioxidant capacity,and the p I5.0 component had the highest total antioxidant capacity,276.33 U/mg Protein,while the digestive fluid of the p I4.0 component had the highest total antioxidant capacity compared to the others.