| In this paper,Se-rich sweet potato from Liaoning Huashi Ecological Base was used as raw material to extract and isolate sweet potato crude protein and analyze its functional characteristics.The crude protein was purified to get sweet potato protein,and the preliminary structure analysis and antioxidant activity analysis of sweet potato protein were carried out.Se-rich sweet potato protein was obtained by alkali extraction and acid precipitation method,and the optimal extraction conditions were determined as follows:solid-liquid ratio of 1:8(w/v),extraction time of 1.3 h and extraction solution p H10.0.At this time,the extraction rate of sweet potato protein is 46.5%.SDS-PAGE analysis showed that the main bands of sweet potato crude protein did not change after selenium enrichment.The main molecular weights of sweet potato crude protein were 22.5 and 56.9 KDa.In the functional characteristics of sweet potato crude protein,the results showed that the solubility,emulsification and emulsification stability,foaming and foaming stability of sweet potato crude protein without selenium were better than that of sweet potato crude protein with selenium.The blank sweet potato crude protein and 2.0 mg/kg Se-rich sweet potato crude protein were purified by DEAE-52 anion exchange column.The crude protein was gradient eluted by Na Cl Tris-HCl buffer solution with gradient concentration.It was found that the main protein could be eluted at 0.2 M Na Cl Tris-HCl.SPP and SPP3,respectively.The purified SPP and SPP3 were analyzed by physical and chemical analysis,SDS-PAGE analysis,spectrogram analysis,thermal stability analysis,amino acid composition analysis,surface morphology analysis and antioxidant activity analysis.The results showed that the basic composition and molecular weight of sweet potato protein did not change significantly after selenium enrichment,but it had more stable secondary structure,better thermal stability,better amino acid composition,and stronger antioxidant activity. |
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