Junren Wen,Yong Sui,Jianbin Shi,Tian Xiong,Fang Cai,Xiaomei Gao,Xin Mei
In this study, the changes in functional properties and binding mechanisms at the molecular level of a non-covalent complex formed between sweet potato leaf polyphenols (SPLPs) and rice bran albumin (RBA) were investigated. Multi-spectral analysis indicated that SPLPs statically quenched the intrinsic fluorescence of RBA, and fitting to a double logarithmic equation revealed that hydrogen bonding constituted the primary driving force behind this interaction. Consequently, the conformational structure, microenvironment, and surface hydrophobicity of RBA were significantly impacted. With 7 μmol/L of SPLPs added to RBA, the emulsifying activity and stability of the complexes were enhanced by 45.71 % and 392.30 %, respectively, compared to RBA. Similarly, the thermal stability of 3,5-diCQA was enhanced by 176.29 %, alongside an improved ultraviolet tolerance. Molecular docking and molecular dynamics simulations clarified that the A0A191ANP5, B8AHL6 and P52428 subunit in RBA has a stronger affinity with the most abundant polyphenols in SPLPs, which was the 3,5-disubstituted caffeoylquinic acid (3,5-diCQA). These findings may furnish a theoretical foundation for the prospective utilization of SPLPs and RBA complex products as functional food ingredients.
Lu Zhang,Zong-cai Tu,Hui Wang,Zhi-feng Fu,Qing-hui Wen,Hai-xia Chang,Xiao-qin Huang
This study aimed to compare the extraction efficiency of dynamic high pressure microfluidization-assisted extraction (DHPMAE) and other commonly used extraction methods on the antioxidant activities (AAs) of sweet potato leaves ( Ipomoea batatas L., SPL), and to identify the antioxidant compounds by HPLC-QTOF-MS 2 . Two highly consumed commercial varieties, orange-fleshed and cream-fleshed sweet potato leaves (OFL and CFL), were taken as materials. OFL was evidenced to be a better antioxidants resource than CFL due to higher polyphenols and AAs. DHPMAE had the best extraction efficiency on total phenolics and total flavonoids , with the values in OFL extract at 16.35 mg GAE/g DM and 16.51 mg RE/g DM, respectively. DHPMAE extract also exhibited the strongest DPPH· and ABTS· + scavenging ability, chelating ability and reducing power. Multiple regression analysis revealed that polyphenols played an important contribution to the AAs of SPL extracts. After successive fractionation of DHPMAE extract by chloroform, ethyl acetate, and n -butanol, the ethyl acetate fraction showed the highest total phenolic (569.38 mg GAE/g Extract) and total flavonoid (43.15 mg RE/g Extract) content, as well as the highest AAs. HPLC-QTOF-MS 2 analysis of the ethyl acetate fraction resulted in identifying 37 compounds including 20 phenolic acids , 12 flavonoids, 3 organic acids, 1 nucleoside and 1 ester, and 20 of them were firstly detected in SPL. Caffeoylquinic acid derivatives and flavonoids were the most abundant antioxidant compounds. The presented results suggested that DHPM might be a promising assisted technology in extracting polyphenols from plants, and SPL could be utilized for the development of functional food.
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