| Alcoholic liver injury is a liver disease caused by long-term and heavy drinking.Since long-term consumption of liver protection drugs has more toxic and side effects,the search for natural foods that can relieve alcohol and protect the liver has become a research hotspot in recent years.Lycium barbarum is a health food material rich in bioactive substances,which has many functions such as tonifying kidney,protecting liver and anti-aging.However,the relatively simple processing and eating methods of Lycium barbarum lead to its bioactive substances cannot be fully utilized,resulting in the functional effect is not obvious.Based on the above,the research takes Lycium barbarum as raw material,select different strains,ang develop a high value-added fermented Lycium barbarum juice through the selection of fermentation process and optimization of conditions,so that it has anti-alcohol and liverprotection effects.The main research contents were as follows:Firstly,the raw materials of Lycium barbarum were collected,which came from six regions of Ningxia,Qinghai,Inner Mongolia,Xinjiang,Hebei and Gansu,and the basic components and active substances of the samples were systematically analyzed.The antioxidant activity in vitro was studied by chemical antioxidant assay(DPPH,ABTS,FRAP and ORAC)and cellular antioxidant activity analysis(CAA).The results reflected Lycium barbarum from Ningxia with the highest content of polysaccharides,total phenols and β-carotene,and Lycium barbarum in Gansu content of total flavonoids was the highest.Additionally,the results of antioxidant activity in vitro showed that Lycium barbarum from Ningxia possesses the strongest chemical antioxidant and biological activities.Secondly,four different microbial strains,containing Lactobacillus bulgaricus,Lactobacillus plantarum,Streptococcus thermophages,and yeast were separately employed to optimize the fermentation conditions of fermented Lycium barbarum juice by using alcohol dehydrogenase(ADH)in vitro screening model and superoxide dismutase(SOD)activity as comprehensive evaluation indexes.The antioxidant activities of Lycium barbarum juice by fermentation of four different microbial strains were compared by using the Hep G2 cell model of alcoholic liver injury.The results showed that Lycium barbarum juice fermented by Lactobacillus plantarum had the highest ADH activation rate,and it fermented by yeast had the highest SOD activity,but the alcohol content was higher than the standard limit.Lycium barbarum juice fermented by Lactobacillus plantarum and yeast could significantly reduce the content of malondialdehyde(MDA)and the leakage rate of lactate dehydrogenase(LDH)in Hep G2 cells,and increase the activity of SOD and the activation rate of ADH.In order to further improve the anti-alcohol ability and reduce alcohol of fermented Lycium barbarum juice,the strategy of mixed strains fermentation was adopted to optimize the fermentation process.The results showed that when yeast was fermented at 29°C and 180 r/min for 12 h,then inactivated them and inoculated with Lactobacillus plantarum at 37°C and 180 r/min for 24 h,the activity of SOD and DPPH radical scavenging ability soluble solid content of fermented Lycium barbarum juice were reached to the peak,which were 468.6 U/m L and 123.07 μmol Trolox(TE)/m L,respectively.Finally,the alcohol content of fermented Lycium barbarum juice was only 1.51%,and the antioxidant capacity in vitro and functional enzyme activity were the best.Finally,the effects of Lycium barbarum puree and Lycium barbarum juice fermented by four different strains on cell oxidative damage were compared.The results showed that fermented Lycium barbarum juice can significantly alleviate oxidative damage in cell compared to unfermented Lycium barbarum puree.It can reduce the content of MDA and leakage rate of LDH in Hep G2 cells,increase the activity of SOD and the activation rate of ADH.The Hep G2 cell model of alcoholic liver injury was used to analyze and verify the anti-alcohol and liverprotection function of the Lycium barbarum juice fermented by mixed strains.The results showed that Lycium barbarum juice fermented by mixed strains were better than those fermented by a single strain,such as Lactobacillus plantarum and yeast.Fermented Lycium barbarum juice fermented by mixed strains significantly reduce the content of MDA,triglycerides and cholesterol in the cell model(52.54%、55.26% and 49.99%,respectively),increase the activity of ADH,SOD,catalase(CAT)and glutathione peroxidase(GSH-Px)(66,4.38,1.62 and 2.44 times respectively),and inhibited the release of Tumor necrosis factor-α(TNF-a)and Interleukin-6(IL-6)(44.12% and 78.44% respectively).At the same time,it possessed better performance in relieving oxidative stress,regulating inflammation and lipid metabolism in cell.This study provides a solution to improve the utilization of bioactive substances of Lycium barbarum.The purpose of this study is to develop a fermented juice with the benefits of anti-alcohol and liver-protection,which is of great significance to promote the development of Lycium barbarum industry and regional poverty alleviation. |
PDF Full Text Request