Formation mechanism of isoprene compounds degraded from carotenoids during fermentation of goji wine

Fermented goji wine as a functional wine is made from yeast fermentation.To our knowledge,fermented goji wine still has a problem with insufficient characteristic aroma.Research has shown that some isoprene compounds with characteristic aromas may improve the aroma of goji wine.Therefore,the present study aimed to investigate the mechanism of isoprene compound production by carotenoid degradation during the fermentation of goji wine.It was found that C1-C6,C5-C6,C6-C7,C7-C8,C8-C9 and C9-C10 were the most easily degraded sites in carotenoids under seven different pretreatment conditions(mechanical treatment,pectinase treatment,adjustment of pH,autoclave treatment,SO_(2) treatment,oxidation treatment and light treatment).Meanwhile,breaking different sites,different aroma contributions such as woody,rose,fruity and grassy aromas were found.Single-factor simulation experiments of goji wine during the fermentation showed that the metabolites in the fermentation process caused the degradation of carotenoids and most were volatile aroma compounds.These results may help improve the brewing process to enhance the aroma of goji wine.