Effect Of Whole-grain Flat Rice Noodles On Intestinal Flora And Its Probiotic Effect

Confucius's saying "never tire of eating"reflects China's traditional diet culture since ancient times.However,with the increasing improvement of people's living standards,the excessive pursuit of grain taste in the refined processing method leads to a large loss of dietary fiber,mineral elements,vitamins and phenols in cereal foods.If things go on like this,people will suffer from chronic diseases caused by nutritional imbalance,such as obesity,type two diabetes and cardiovascular diseases.Whole grain food refers to the whole,crushed,broken or pressed caryopsis.The basic components include starchy endosperm,germ and bran.The relative proportion of each component is the same as that of the whole caryopsis.Whole-grain flat rice noodles(WFRN)made from brown rice may have a positive effect on increasing the consumption of whole grain food and improving the health of consumers.Therefore,this paper studied the basic nutrients,vitamins,mineral content and antioxidant activity of WFRN,the digestion and fermentation characteristics of WFRN in vitro,the preventive effect of WFRN on hyperlipidemia,liver disease and the improvement of intestinal flora in mice.The results are as follows:(1)The contents of protein,fat,dietary fiber,vitamins dominated by group B vitamins and mineral elements such as sodium,potassium,magnesium,calcium,iron,manganese and zinc in WFRN were significantly higher than those in normal flat rice noodles(NFRN)(p<0.05).WFRN also showed significant advantages in DPPH radical scavenging ability and iron reduction ability,reaching 71 ± 2.1%and 18 ±1.3%respectively.WFRN retained the whole grain nutrients better.(2)In vitro digestion experiment.the predicted glycemic index(EGI)(73,86)of WFRN group was significantly lower than that of NFRN group(85.48)(p<0.05),indicating that WFRN had slow digestion,low absorption rate and slow glucose release.In the process of in vitro fermentation,two experimental groups of WFRN and NFRN and two control groups of blank(control)and positive(FOS)were set to intervene the intestinal flora of healthy young people in vitro.With the extension of fermentation time,both WFRN and NFRN significantly reduced the pH value of fermentation broth(p<0.05),but there was no significant difference between them(p>0.05).The contents of acetic acid,propionic acid and butyric acid in the WFRN group were 10.84 ± 0.16,2.86 ± 0.05 and 2.68± 0.13,respectively.All of them were significantly higher than those in the NFRN group(p<0.05).High throughput sequencing results showed that with the extension of fermentation time,there was no significant change in the abundance of bacteria in the fermentation broth of WFRN and NFRN groups,but the diversity decreased.WFRN could promote the reproduction of Bifidobacterium and Megamonas and inhibit the growth of pathogenic bacteria.(3)In the vivo experiment,WFRN supplementation significantly reduced the body weight gain,Lee's index and body fat rate(p<0.05),and improved the obesity degree of obese mice;It also decreased the levels of total cholesterol(TC),triglyceride(TG),low density lipoprotein cholesterol(LDL-C)and increased the level of high density lipoprotein cholesterol(HDL-C)in the serum of mice;At the same time,it has a protective effect on the liver and intestine.In addition,the total fatty acids in cecum of mice fed WFRN diet were 272.97 ± 59.26.Meanwhile,the ratio of Firmicutes/Bacteroidota in the HFD group significantly decreased from 81.4 to 34.7;The relative abundance of Desulfobacterta also decreased from 14.8%to 5.0%;However,the relative abundance of probiotics such as Akkermansia and Roseburia increased,while the abundance of harmful bacteria such as Desulfovibrio,Aerococci,Corynebacterium and Helicobacter decreased significantly(p<0.05).