Preparation of spore‐immobilized glutathione reductase and its application in inhibiting browning of pear wine

Abstract

BackgroundBrowning is the key problem to hinder the industrialization of pear wine. The use of high‐yield glutathione Saccharomyces cerevisiae in the fermentation of pear wine can inhibit the browning. Glutathione reductase (GR) can ensure the reduction of glutathione. Spore immobilization enzyme is a new technology. It is a new attempt to apply spore immobilized GR in combination with high‐yield glutathione Saccharomyces cerevisiae to inhibit browning of pear wine.ResultsUsing Saccharomyces cerevisiae spore immobilization enzyme technology to immobilize glutathione reductase (GR) in the spores of mutant S. cerevisiae dit1∆, osw2∆, chs3∆ and wild‐type S.cerevisiae wt. The enzyme activity of GR immobilized by chs3∆ spores was the highest of 3.08 U/mg/min. The chs3∆ spore‐immobilized GR had certain resistance to ethanol, citric acid, sucrose, glucose and proteinase K. Electron microscopy analysis showed that the spore wall of chs3∆ had moderate size holes, which might be the main reason why it immobilized GR had the highest enzyme activity. And the GR was immobilized between prespore membrane and mannoprotein layer of the spore wall. Added chs3∆ spore immobilized GR(chs3∆‐GR) to the Dangshan pear wine fermented by the high‐yield glutathione (GSH) S. cerevisiae JN32‐9, the presence of chs3∆‐GR could further protect amino acids, polyphenols and glucose from oxidation, thereby reducing the browning of pear wine during storage by 47.32%.ConclusionGR immobilized by S. cerevisiae spores was effective in inhibiting the browning of pear wine, the method was simple, green, effective and did not increase the production cost of pear wine.This article is protected by copyright. All rights reserved.