Research On Wolfberry Wine

Lycium barbarum L.is a traditional Chinese medicinal material which is widely used in food processing due to its health efficacy.China is the main producer and consumer of wolfberry in the world.Wolfberry wine can retain a variety of nutrients in wolfberry juice,which not only enriches the market of wolfberry products,but also helps increase the added value of its products,and can efficiently solve the problem of waste caused by extreme seasonality of wolfberry.This paper analyzed wolfberry from different origins,and selected a yeast strain suitable for fermentation,then optimized the brewing process of wolfberry wine.The main research results obtained are as follows:Firstly,analyzed the physical and chemical indexes,active substance content and flavor substances of wolfberry from four producing areas of Ningxia,western Inner Mongolia,Xinjiang and Qinghai.Selected Ningxia Zhongning wolfberry which had higher active substance content as the raw material.The strain EC1118 was obtained by combining the analysis of flavor compounds and sensory evaluation,which had a high fermentation rate and the typical aroma of wolfberry.Next,selected SO₂ addition,yeast inoculum,initial sugar content and fermentation temperature as single factor,sensory evaluation and Lycium barbarum polysaccharide(LBP)content as indicators,and then optimized the brewing process of wolfberry wine by response surface analysis.The test results showed that the optimal fermentation process for wine was 20mg·L^-1 of SO₂,0.8×10⁷CFU·m L^-1 of inoculation,230 g·L^-1 of initial sugar,and temperature of21.5?.The indicators of wine under this condition were determined as follows:alcohol content10.86±0.14%v·v^-1,titration acid 6.12±0.13 g·L^-1,residual sugar 5.84±0.10 g·L^-1,LBP content935.13±7.95 mg·L^-1,total flavonoids content 356.05±5.68 mg·L^-1.The physiochemical properties of wolfberry juice,fruit wine and three commercially available fruit wine samples were detected.The results showed that the tested wolfberry fruit wine had a rich variety of organic acids and the content of amino acids in it was the highest.Comparing total flavonoids and LBP content of four samples,it was found that the indexes in wolfberry wine were 2-3times higher than those in commercial wolfberry wine.Finally,the volatile aroma in wolfberry fruit wine was analyzed by GC-MS and OAV.The results showed that toluene,phenol acetate,phenethyl alcohol,isoamyl acetate,benzene isovalerate,hexanoic acid toluene,n-nonanol,n-propanol,isoamyl alcohol,caprylic acid,caproic acid were the main flavor compound of wolfberry fruit wine.Compared with the original wine,the wolfberry fruit wine had a richer aroma after aging with oak chips.The recommended aging process is 3 g·L^-1 of oak chips,and the aging time is 60 days.