Study On The Change Law Of Fusel Oil In Jujube Wine Fermentation Process

China is the main producing country of jujube.The total output of the jujube date was 9.35 million tons in 2015.However,The jujube in the market are mainly sold by the original date,the deep processing product is less.As the production of jujube increases year by year,the surplus of the jujube is due to rot and throw away,causing a lot of waste.Jujube wine is a kind of beverage which is made of jujube date,which has high nutritional value and broad market prospect.But during the production of jujube wine,the fusel oil and other harmful substances will form which seriously affect the quality and taste of jujube wine.In order to reduce the formation of fusel oil in jujube wine and provide a theoretical basis for the production of jujube wine,it is necessary to study on the change of fusel oil during fermentation process.In this article,Xinjiang jujube was used as raw material.The effect of juice extraction,fermentable sugar,SO₂ addition,the main fermentation temperature,yeast,yeast addition in the fermentation process on the changes of fusel oil was explored.The main contents:1.The gas phase detection method of fusel oil in jujube wine was optimized.Meanwhile,the Capillary Column Chromatography of sec-butyl alcohol,propyl alcohol,n-butyl alcohol,isobutyl alcohol and isoamyl alcohol was built.The samples were separated by HP-INNO-WAX capillary column and determined by gas chromatography flame photometric detector?FID?,the five kinds of fusel oil could be completely separated.The fusel oil had a good linear relationship in the concentration range of the test?R2>0.9999?,the recovery rate was within the range of 99.1?100.7%and the relative standard deviation was within the range of 0.3%-0.47%.The method is rapid and has high precision and accuracy,it is suitable for detecting the content of fusel oil in fermented jujube wine.2.The extraction of red jujube juice by enzyme solution and hot water was obtained.The results showed that using enzyme extract juice fermented jujube wine than hot water extract juice are more likely to produce fusel oil.Compared with the latter,the alcohol,isopropyl alcohol and isoamyl alcohol were increased by 28.9%,22.6%and 23.2%,respectively.Under the condition of two kinds of juice extraction methods,the change of propyl alcohol,isobutyl alcohol and isoamyl alcohol were all increased first and then decreased slowly,and reached the peak at 7d,1.262g/L and 1.070g/L,respectively.3.The jujube juice?SSC of 10%?were added sucrose,glucose and direct concentration.When the SSC value was up to 20%,carried out the alcohol fermentation.The results showed that the changes of fusel oil which was in the fermentation broth added sucrose and glucose was first increased and then decreased stability and had no significant difference.The addition of sucrose and glucose had little effect on the formation of fusel oil in jujube wine.But the content of fusel oil was much higher than the jujube wine which was used concentrated jujube juice as fermentation broth.4.Different additions of SO₂ had significant difference on the formation of fusel oil.With the increase of the addition of SO₂,the fusel oil decreased gradually which indicated that SO₂ had inhibitory effects of fusel oil.But when the addition of SO₂ was too large,the fermentation liquor had low precision,high residual sugar content which will do harm to the quality of wine.Therefore,it is necessary to consider the appropriate amount of SO₂ addition.5.Fermentation temperature is one of the most important factors of the formation of fusel oil.The results showed that under the same fermentation time,three kinds of fusel oil were increased with the increase of fermentation temperature.During the same period?11d?,fusel oil in the jujube wine which was fermented under low temperature had been in a slow rising state.With the increase of fermentation temperature,changes of the fusel oil was increased first and then decreased and the decrease trend was increased gradually with the increasing temperature.6.FX10,DV10,EC 118,RC212,Angel yeast were used to ferment the jujube juice.The results showed that fusel oil in the fruit wine which was fermented by using Angel yeast was apparently higher than that in the fruit wine which was fermented by using other yeasts and the variation was different.The content was 0.680g/L which was less than the national standard 2g/L.The alcohol content of jujube wine which was fermented with Angel yeast was higher than others.The alcohol content was 9.61%.Therefore,Angel active yeast was chosen as the yeast.7.The changes fusel oil in jujube wine which was fermented with Angel yeast were all increased first and then decreased with the increase of yeast addition.When the addition of yeast was 0.5g/L,the fusel content was reached the maximum.The content of propyl alcohol,isobutyl alcohol and isoamyl alcohol were 0.035g/L,0.127g/L and 0.879g/L,respectively.8.The results showed that the content of isoamyl alcohol in the frying oil produced during the fermentation was the highest,accounting for more than 80%of the total fusel oil.The different factors in the yeast not only affect the amount of fusel oil production and change the proportion of the total amount of fusel oil in the total.