晒青毛茶液态发酵茶褐素特征及其对α-葡萄糖苷酶活性抑制作用

Characterization and inhibition of α-glucosidase activity of theabrownins from liquid-state fermentation with sun-dried green tea

目的 研究由茶泛菌(Pantoea camelliae,CCTCC AB 2021544T)液态发酵晒青毛茶所得茶褐素的组成结构与功能活性。方法 以固态发酵茶褐素(soild-state fermented theabrownins,S-TBs)为对照,通过紫外可见光谱法(ultraviolet-visible spectroscopy,UV-Vis)、傅里叶红外光谱法(Fourier transform infrared spectroscopy,FT-IR)、居里点热裂解气相色谱-质谱法(Curie point pyrolysis gas chromatography-mass spectrometry,CP-Py-GC-MS)、扫描电子显微镜(scaning electron microscope,SEM)、Zeta电位测定仪等手段对液态发酵茶褐素(liquid-state fermented theabrownins,L-TBs)进行表征。同时,检测了不同浓度L-TBs对α-葡萄糖苷酶活性的抑制作用。结果 与S-TBs相比,L-TBs颗粒较小、分散度及稳定性较好,但二者都含有丰富的羟基和羧基,p H呈弱酸性,总蛋白、总糖含量较高,且没有显著差异;L-TBs和S-TBs热裂解产物主要是酚类物质,含量分别为43.88%和35.69%;进一步研究发现,L-TBs对α-葡萄糖苷酶活性具有一定的抑制作用,并在一定范围内呈剂量关系。结论 茶泛菌L-TBs在组成结构方面与S-TBs较一致,具有很好的开发和应用价值。

Objective To explore the composition,structure,and functional activity of the theabrownins obtained from the liquid-state fermentation with sun-dried green tea by Pantoea camelliae(CCTCC AB 2021544T).Methods With the solid-state fermented theabrownins(S-TBs) as a control,the liquid-state fermented theabrownins(L-TBs) was characterized by ultraviolet-visible spectroscopy(UV-Vis),Fourier transform infrared spectroscopy(FT-IR),Curie point pyrolysis gas chromatography-mass spectrometry(CP-Py-GC-MS),scanning electron microscopy(SEM),and Zeta potential determination. Meanwhile,the inhibitory effects of L-TBs with different concentrations on α-glucosidase activities were examined. Results Compared with S-TBs,L-TBs had smaller particles,better dispersion,and stability,but all contained abundant hydroxyl and carboxyl groups,weakly acidic pH,and higher total protein and total sugar content without significant differences. The pyrolysis products of L-TBs and S-TBs were mainly phenolics with content of 43.88% and 35.69%,respectively. It also revealed that L-TBs had a specific inhibitory effect on α-glucosidase activity with a dose relationship in a particular range. Conclusion The L-TBs by Pantoea camelliae are more consistent with S-TBs in terms of composition structure,which has good value for developing and applying theabrownins products.