Release characteristic of bound polyphenols from tea residues insoluble dietary fiber by mixed solid-state fermentation with cellulose degrading strains CZ-6 and CZ-7

The purpose of this work was to investigate the release characteristic of bound polyphenols (BP) from tea residues insoluble dietary fiber (IDF) by mixed solid-state fermentation (SSF) with cellulose degrading strains CZ-6 and CZ-7. The results implied that cellulase, & beta;-glucosidase and filter paper lyase activities were strongly correlated with the BP content. The scanning electron microscop and fourier transform infrared spectroscopy manifested that the cellulose network of the IDF was decomposed and dissolve, forming more loose fibrous structure. Additionally, 28 polyphenols components were detected and their biotransformation pathways were preliminary speculated. Moreover, the BP obtained by mixed SSF produced prominent inhibitory activities against & alpha;-glucosidase and & alpha;-amylase, as well as exhibited significant scavenging effects on DPPH & BULL;, ABTS+& BULL; free radicals and ferric reducing antioxidant power. These findings could further promote the utilization of BP from agricultural by-products in a more natural and economical method, CZ-6 and CZ-7 strains provide a new approach to expound the release and conversion of BP.

Automated summary

The purpose of this study was to investigate the release characteristic of bound polyphenols (BP) from tea residues insoluble dietary fiber (IDF) through mixed solid-state fermentation (SSF) with cellulose degrading strains CZ-6 and CZ-7. The results showed that activities of cellulase, β-glucosidase, and filter paper lyase were strongly related to the BP content. Microscopic and spectroscopic analysis indicated that the cellulose network of IDF was decomposed and dissolved, resulting in a more loose fibrous structure. In addition, the study detected 28 polyphenols components and speculated their biotransformation pathways. Moreover, the BP obtained through mixed SSF showed significant inhibitory activities against α-glucosidase and α-amylase, as well as strong antioxidant effects. These findings could enhance the utilization of BP from agricultural by-products in a more natural and economical manner, and the CZ-6 and CZ-7 strains provided a new approach to understand the release and conversion of BP.