Study Of Microbial Fermentation On Chemical Components Of Wheat Bran And Its Functional Properties

Wheat bran is of interest because it contains numerous active ingredients,however,wheat bran is limited in practical application due to its overly complex and dense woody fiber structure and the presence of the antinutritional factor phytic acid,while the quality of wheat bran is significantly improved and the flavor is altered by using fermentation treatment.In this study,four microorganisms,Lactobacillus plantarum,Saccharomyces boulardii,Bacillus subtilis and Aspergillus niger,were used to ferment wheat bran to investigate the changes in metabolic enzyme activities and active ingredients during the fermentation process,and then animal models were used to determine the effects of intestinal flora and the effects on cookie quality.The main results were as follows:1.The changes in cellulase,xylanase and phytase activities and soluble pentosan(WEAX),total phenol and phytic acid contents during the fermentation of the four microorganisms were determined.The study showed that the effect of metabolizing cellulase and xylanase production was Aspergillus niger > Saccharomyces boulardii > Bacillus subtilis > Lactobacillus plantarum in order,and the effect of metabolizing enzyme activity of phytase was Aspergillus niger > Bacillus subtilis > Lactobacillus plantarum >Saccharomyces boulardii;in terms of active ingredients,the changes of WEAX content and total phenol content were Aspergillus niger > Saccharomyces boulardii > Bacillus subtilis > Lactobacillus plantarum in order,and phytic acid The degradation effect in the order of Aspergillus niger >Saccharomyces boulardii > Bacillus subtilis > Lactobacillus plantarum.Set the optimization index by the improvement effect of active ingredients,take the wheat bran fermented by Lactobacillus plantarum and Bacillus subtilis for 11 days,Saccharomyces boulardii for 5days and Aspergillus niger for 2 days.Taking into account the changes in active ingredients,the microorganism with the best enhancement effect was Aspergillus niger,followed by Saccharomyces boulardii and Bacillus subtilis,and Lactobacillus plantarum was relatively weak.Total dietary fiber(TDF),insoluble dietary fiber(IDF)and soluble dietary fiber(SDF)were significantly(P < 0.05)elevated by the fermentation of the four microorganisms.All four fermented bran color changes were recognizable to the naked eye,with the most significant change in the Aspergillus niger fermented bran(ANWB)group.The water holding capacity and oil holding capacity of fermented wheat bran were significantly increased,and the water absorption and swelling capacity were significantly reduced.The antioxidant capacity of all four fermented bran groups was significantly(P<0.05)improved compared to the RWB group,with the ANWB group showing the most significant improvement in DPPH,hydroxyl radical scavenging and reducing power;the Bacillus subtilis fermented bran(BSWB)group was the next most effective,with the most significant effect of ABTS radical scavenging,and DPPH radical scavenging and reducing power were second only to the ANWB group.2.By dividing eight-week-old Kunming mice into normal control(CN),raw bran(RWB),Lactobacillus plantarum fermented bran(LPWB),Brady’s fermented bran(SBWB),BSWB,and ANWB groups,the mice were fed with a mouse growth diet containing 20%wheat bran for 21 days at a temperature of 20-26℃ in the animal room to investigate the effects of fermented bran on mouse growth,lipid metabolism,inflammatory factors,and functional properties of intestinal flora in mice.The study showed that the intake of fermented bran,especially in the LPWB,SBWB and BSWB groups,significantly(P < 0.05)reduced the body weight of mice compared to the CN and RWB groups.Regarding the organ indices,the renal indices were significantly(P< 0.05)reduced in all experimental groups,while the SBWB,BSWB and ANWB groups were significantly(P < 0.05)elevated in the liver indices compared to the CN and RWB groups.In terms of short-chain fatty acids,the fermented bran group had a higher content of short-chain fatty acids than the CN and RWB groups,with the most significant(P < 0.05)elevation in acetic acid,propionic acid,butyric acid,and valeric acid in the feces of mice in the SBWB group.The intake of fermented bran significantly(P < 0.05)improved lipid metabolism,and the cholesterol(TCH)content and triglyceride(TG)content in the SBWB,BSWB,and ANWB groups were significantly(P <0.05)lower than those in the CN and RWB groups,and the low-density lipoprotein cholesterol(LDL-c)content in the BSWB group was significantly(P < 0.05)lower.In terms of inflammatory factors,the SBWB and BSWB groups had the most significant effect(P <0.05),and their IL-6 and TNF-α were significantly lower and their IL-10 content was significantly higher than those of the CN and RWB groups.In this study,the bioinformatics of mice were analyzed by high-throughput sequencing of 16 S r RNA V4-V5,and according to OTUs showed that the number of OTUs was significantly elevated in the fermented bran group compared with the CN and RWB groups,with the most significant effect in the BSWB and SBWB groups.Alpha Diversity index analysis showed that the BSWB and ANWB groups had the greatest advantage in increasing species abundance and The results of UPGMA cluster tree analysis showed that the CN and RWB groups were the closest in species structure,and the BSWB and ANWB groups had the most significant differences in species composition compared to each other.The results of LEf Se analysis showed that at the phylum level,the differential species in the CN and ANWB groups were Verrucomicrobiota,Bacteroidia;at the family level,the differential species in the CN group were Izemoplasmatales,the differential species in the RWB group were Erysipelotrichaceae,Mitochondria,Syntrophobotulaceae,and the differential species in the LPWB group were Syntrophomonadia,Caminicellaceae,and Muribaculaceae for the BSWB group.in addition,the differential species for the SBWB group were g＿Candidatus-Stoquefichus,and Lachnospiraceae.In conclusion,fermented bran significantly improved the composition of the intestinal flora as well as enhanced the diversity of the intestinal flora,significantly increasing the abundance of Bacteroidia and decreasing the abundance of Verrucomicrobiota.3.The study of the processing characteristics of fermented bran was investigated by studying the effect of adding fermented bran on the quality of dough and cookies.The fermented bran improved the increase in dough hardness due to the addition of raw bran,and the viscosity and elasticity were improved compared to the CN group;the cohesiveness decreased with the addition of raw bran,and the most significant improvement was observed in ANWB.The color of fermented bran cookies changed significantly and the sensory evaluation scores improved compared to RWB,but there was no significant difference.The specific volume of the fermented bran group was significantly(P < 0.05)lower than that of the CN group and improved compared to the RWB group,but there was no significant difference.In terms of texture,the hardness of fermented bran cookies was significantly(P <0.05)improved compared to the CN group,but improved compared to the RWB group;the crispness of fermented bran cookies was significantly improved compared to the RWB,and the chewiness was significantly reduced compared to the RWB group except for the SBWB group.In summary,the quality of fermented bran cookies improved compared to the RWB group.58 flavor substances were detected by GC-MS,and alcohols,aldehydes,esters and aromatic heterocyclic amines were significantly improved in the cookies after the addition of fermented bran.In terms of antioxidant capacity,the antioxidant capacity of fermented bran cookies were all significantly(P < 0.05)higher than those of the RWB and CN groups,with the best reducing power and ABTS radical scavenging in the BSWB group,and the best hydroxyl radical scavenging and DPPH radical scavenging in the ANWB group.In conclusion,the texture of dough made from fermented bran was improved,and the stability of gluten network structure was significantly improved;meanwhile,the texture of bran cookies was significantly improved,and the antioxidant capacity was significantly improved.