Study On Low Methanol Brewing Technology Of Xinjiang Jujube Brandy

Jujube is rich in pectin,and it is easy to produce excessive methanol when brewing brandy.In this experiment,dried jujube from Xinjiang are used as raw materials,and the effects of different raw material pretreatment and fermentation processes on the methanol content in jujube brandy and the effects of aging oak chips with different toasting degrees on aroma components are explored and finally determined the best brewing process.The main test results are as follows:1.Using methanol content as the inspection index,according to the single factor test results,combined with response surface test,the pretreatment process of jujube brandy is optimized.The results showed that the best pretreatment process for low-methanol jujube brandy is: boiling time 11 min,enzymolysis temperature 46?,RF pectinase addition 1.10 m L/kg,enzymolysis time 6.00 h.Under these conditions,the methanol content is 1.37 g/L,and the alcohol content is 31.50% Vol.2.Using fuzzy comprehensive sensory evaluation scores as the evaluation indicators,based on single factor and response surface tests to explore the optimal fermentation process for jujube brandy.The results showed that the best fermentation process for low-methanol jujube brandy is: fermentation time 7 days,fermentation temperature 25°C,and yeast strain addition amount of 0.09%.The jujube brandy,under this optimized condition,is clear and transparent,and has a harmonious aroma,full and mellow,with a fuzzy sensory score of 87.81 points and a methanol content of 1.46 g/L.3.Jujube brandy is aged by lightly,moderately,and heavily toasted oak chips to monitor the change of methanol content.The results showed that the methanol content in the jujube brandy aged by the three oak chips do not change significantly after 12 months of aging.4.The aroma components of jujube brandy are determined by GC×GC-TOFMS,and the difference of volatile aroma components in jujube brandy aged by lightly,moderately and heavily roasted French oak chips is explored.The results showed that a total of 231 aroma components are detected in the three jujube brandies.Among them,esters,aldehydes,terpenes and alkanes have the highest content in the wine samples aging of lightly toasted oak chips,and alcohols have the highest content in wine samples aging of moderately toasted oak chips.The content of acids,ketones and other substances are the highest in the wine samples that are accelerated by the aging of the heavily toasted oak chips.By comparing the types and contents of the aroma components in the three brandies,it is found that the moderately toasted oak chips are more suitable for aging the jujube brandy.By optimizing the pretreatment,fermentation and aging process,jujube brandy with lower methanol content and higher organoleptic quality can be obtained.