Improving The Physicochemical Indexes And Antioxidant Activities Of Hongqu Rice Wine By Hongqu Rice And Rice Bran

Wine,Chinese rice wine and beer,were known as the world's three brewing wines.As an important branch of Chinese rice wine,Hongqu rice wine has a long history of drinking in China.Hongqu rice wine is rich in phenolics,small molecular peptides,proteins and amino acids and other active substances.It is also an important health wine in China.In this paper,based on the preliminary experimental results of the our research group,the brewing conditions of Hongqu rice were further optimized to obtain Hongqu rice wine with higher total ester.We analyze the correlation between the Hongqu rice and the phenolics content,components and the antioxidant activity of Hongqu rice wine.Also,we explore the contribution of Hongqu rice to the antioxidant activity of Hongqu rice wine.At the same time,in order to improve the content and components of phenolics in Hongqu rice wine,rice bran,a by-product of rice milling in agriculture,was applied to the brewing of Hongqu rice wine.The main research results were as follows:(1)Optimizing the post-fermentation time and post-fermentation temperature of Hongqu rice wine to obtain the best fermentation conditions.By optimizing the post-fermentation time and post-fermentation temperature,the content of total esters in Hongqu rice wine can be effectively increased,and the total phenolics in Hongqu rice wine can also be increased.The time of post-fermentation significantly affected the total ester of Hongqu rice wine.The total ester content of Hongqu rice wine was 3995.55 mg/L on the 15th day of post-fermentation time,which was 1.63 times higher than that on the 7th day of post-fermentation time.For total phenolics,post-fermentation time also had a significant impact.The total phenol content of Hongqu rice wine on the 15th day was 1.38 times of that on the 7th day,so the optimal post-fermentation time was the 15th day.Under the optimum post-fermentation time,the total esters of Hongqu rice wine were also significantly affected by the post-fermentation temperature,too low temperature was not conducive to the formation of esters,but when the temperature increased to a certain extent,the total esters increased slowly.When the post-temperature is 25?C,the total esters of Hongqu rice wine had a maximum value of3920.18 mg/L,which was significantly different from the total esters at low temperature(p<0.05).Correspondingly,the total phenolics content of Hongqu rice wine was 332.36 mg/L at25?C.The increase of post-fermentation temperature was not conducive to the increase of total phenol content of Hongqu rice wine.Therefore,considering the flavor,antioxidant properties and cost production of Hongqu rice wine,the optimal post-fermentation temperature was25?C.(2)The effects of Hongqu rice on phenolics and antioxidant activity of Hongqu rice wine were studied.The total phenolics content of wine samples increased with the increase of addition amount,which was consistent with the result of DPPH free radical scavenging capacity,ABTS~+free radical scavenging capacity and reducing power determination by FRAP method.The Component and content of monomeric phenolic acids in red yeast wine increased with the increase of addition amount of Hongqu rice.The contents of gallic acid,chlorogenic acid,p-hydroxybenzoic acid,rutin sinapic acid and ferulic acid reached 5.54 mg/L,11.33mg/L,3.18 mg/L,9.14 mg/L,12.42 mg/L and 4.46 mg/L,respectively,when the addition amount was 10%,which were 1.83,4.21,4.21,6.01,8.12 and 2.34 times respectively compared with the 0%addition amount.Quercetin can only be detected in Hongqu rice wine when the addition amount of Hongqu rice increases to a certain size.The correlation analysis showed that sinapic acid,ferulic acid and rutin were highly correlated with total antioxidant capacity,DPPH and ABTS~+free radical scavenging capacity and reductive capacity of addition wine(r>0.890,P<0.05).(3)The addition of rice bran can improve the phenolics and antioxidant activity of Hongqu rice wine.Compared with the control group,the total phenolics content of Hongqu rice wine with10%and 14%rice bran addition was 618.24 mg/L and 694 mg/L,respectively,which increased by29.29%and 45.14%.The results of different antioxidant capacity showed similar trend,that was,with the increase of rice bran content,the antioxidant capacity of Hongqu rice wine also increased.Among them,the amount of rice bran addition had the greatest influence on the reductive power of Hongqu rice wine.The reductive power of Hongqu rice wine with 10%and 14%rice bran addition was 2.66 and 3.16,respectively,times of that of blank group.The scavenging capacity of DPPH and ABTS~+radicals increased by about two to one times.Gallic acid,chlorogenic acid and ferulic acid were the main components of phenolics in rice bran added Hongqu rice wine.Their contents were 36.28mg/L,14.55 mg/L and 6.82 mg/L,respectively,at 14%rice bran addition,which were 6.55,1.28and 1.53 times higher than that of Hongqu rice wine with 0%rice bran addition,respectively.When the rice bran addition was 10%,the contents of gallic acid,chlorogenic acid and ferulic acid in Hongqu rice wine were 29.73 mg/L,14.10 mg/L and 5.67 mg/L,respectively,which were 22.03%,3.1%and 20.28%lower than those in 14%addition.Compared with the blank group,new phenolic acid,vanillic acid and p-coumaric acid were detected in Hongqu rice wine with rice bran addition.With the increase of rice bran addition,vanillic acid and p-coumaric acid in Hongqu rice wine increased,too.Finally,the sensory evaluation of the wine sample was detected,for the overall score of red yeast wine Hongqu rice wine,with the increase of the addition amount of rice bran,the score is gradually increased,but when the amount of rice bran addition is greater than 10%to 14%,the score decreases,only 60.Therefore,combined with the previous phenolics content and antioxidant activity,the optimal amount of rice bran addition is 10%.Under this rice bran addition amount,the total sensory evaluation score of Hongqu rice wine is 92,which has the maximum value.This paper explored the relationship between phenolic content in Hongqu rice wine and Hongqu rice,and improved the phenolic content of Hongqu rice wine by adding rice bran to develop new type Hongqu rice wine.It also provided a reference for improving the application value of rice bran,an agricultural by-product in China.