Antioxidant Activity And Intestinal Probiotics Regulation Of Brown Rice Using In-vitro Model

Intake of whole grains prevents chronic and metabolic diseases effectively,which attracts more attention in recent years.Brown rice is one of the most common whole grains which is rich in nutritional components and it has good physiological effect.The main purpose in this research is about analyzing the basic nutritional and functional components in different varieties of brown rice as well as with high quality around China.Then,analysis on the dynamic change of the phenolic release amount with digestion time of brown rice and antioxidant activity were conducted.The effect of different processing methods on the intestinal probiotics in-vitro fermentation were studied.The aim is to provide theoretical basis for selection high-quality raw materials of brown rice processing products and consumers' dietary guidance.The results were showed as followed:(1)Analysis of quality of raw brown rice.23 different varieties of brown rice grown in China were collected.Then basic nutritional components were analyzed.There is no significant difference in basic nutritional components between Japonica and Indica brown rice(p>0.05).The variation coefficient of crude protein,crude fat and dietary fiber were higher,but total starch was lower.The content of polyphenols in Japonica brown rice was higher than Indica brown rice.According to principal component analysis of correlation between quality indexs of brown rice,the variance contribution value of polyphenols and crude protein(PC1 and PC2)reached 65.3%(Japonica)and 70.8%(Indica),and Japonica and Indica brown rice in different regions were divided into two categories.(2)Study on release of polyphenols and antioxidant activity during in-vitro digestion of brown rice.Gastric and intestinal digestion promoted the release of free phenolic,and the release amount of phenolic was higher in Japonica brown rice than compared with Indica brown rice(p<0.05).The dynamic change of the phenolic release amount with digestion time of the two varieties of brown rice was in accordance with the power function model.Results of ferric-reducing antioxidant power(FRAP)and oxygen radical absorbance capacity(ORAC)showed that digestion production of brown rice had great antioxidant activity.The trend of FRAP was consistent with the change of free phenolic.The ORAC was significant higher in Japonica brown rice than that in Indica brown rice in intestinal digestion(p<0.05).(3)Study on the intestinal probiotics of brown rice during in-vitro fermentation.The pH value declined and the value of Lactobacillus,Bifidobacterium were increased significantly(p<0.05)that inhibited the growth of Enterobacteriaceae and Clostridium during 24 h fermentation of brown rice.The production of acetic acid and propionic acid increased significantly during fermentation(p<0.05).The content of bound phenolic in the hydrolysate declined significantly(p<0.05).Results showed that intestinal probiotic was better of Japonica brown rice during fermentation in-vitro.(4)Effect of processing methods on the intestinal probiotic of brown rice.The numbers of Lactobacillus and Bifidobacterium(p<0.05)increased in-vitro digestion during fermentation.On the one hand,the effect of increasing Bacteroides was better with roller drying,high pressure steaming.On the other hand,roller drying and baking were more effective in terms of inhibition Enterobacteriaceae and Clostridium.There is no significant difference was observed in acetic acid and propionic acid production during brown rice fermentation treated by different processing methods(p>0.05).It was considered the effect of roller drying and high pressure steaming is optimal.