Effects of insoluble and soluble fibers isolated from barley on blood glucose, serum lipids, liver function and caecal short-chain fatty acids in type 2 diabetic and normal rats

Impact of milling on the nutrients and anti-nutrients in browntop millet (Urochloa ramosa) and its milled fractions: evaluation of their flour functionality

BACKGROUND

Browntop millet has gained popularity in recent years owing to its nutritional superiority and health benefits. However, the usage of browntop millet flours as ingredients in composite flours and functional foods is constrained due to a lack of information regarding the grain composition and its flour functionality. Therefore, the distribution of nutrients, anti-nutrients in browntop millet milled fractions and their flour functionality was evaluated in comparison to whole grain flour.

RESULTS

Bran fraction comprised the highest protein (13.7%) and fat contents (27%) among other fractions. Pearling of dehulled grains considerably reduced phytic acid, saponins and flatulence-causing oligosaccharides in pearled grain flours. Besides, this led to the enrichment of soluble fibre, minerals, phenolics and trypsin inhibitors in bran fraction. Milling also impacted flour functionality. Despite its lower water holding ability, dehulled grain flour exhibited significantly higher oil absorption capacity than whole grain flour due to the removal of fibre-rich hull fraction. Although emulsion (45.2%) and foaming capacities (12.5%) were superior in bran flour, foam stability was greater in pearled grain flours.

CONCLUSION

These findings suggest the potential utilisation of browntop millet milled flours as ingredients in the development of distinct food formulations and as partial substitutes to wheat flour in confectionary and bakery products. © 2024 Society of Chemical Industry.

Carboxymethylated Lycium barbarum seed dreg dietary fiber alleviates high fat diet-induced hyperlipidemia in mice via intestinal regulation

In this study, we investigated the ameliorative gut modulatory effect of carboxymethylated Lycium barbarum seed dreg insoluble dietary fiber (LBSDIDF) on hyperlipidemic mice. After seven weeks of insoluble dietary fiber (IDF) intervention, the results demonstrated that IDFs effectively inhibited body weight gain, with slimming and hypolipidemic effects, and improved liver histopathology by decreasing ALT, AST, TNF-α and IL-6, and increasing short-chain fatty acid (SCFA) levels in hyperlipidemic mice. With the increasing diversity and abundance of intestinal bacteria and decreasing ratio of Firmicutes to Bacteroidetes, intestinal flora facilitated cholesterol lowering effects in hyperlipidemic mice. Our research offers a novel concept for the use of LBSDIDF as a prebiotic to improve intestinal dysbiosis or as a preventive measure against obesity and dyslipidemia.

Modulating the Gut Microbiota and Metabolites with Traditional Chinese Medicines: An Emerging Therapy for Type 2 Diabetes Mellitus and Its Complications

Currently, an estimated 537 million individuals are affected by type 2 diabetes mellitus (T2DM), the occurrence of which is invariably associated with complications. Glucose-lowering therapy remains the main treatment for alleviating T2DM. However, conventional antidiabetic agents are fraught with numerous adverse effects, notably elevations in blood pressure and lipid levels. Recently, the use of traditional Chinese medicines (TCMs) and their constituents has emerged as a preferred management strategy aimed at curtailing the progression of diabetes and its associated complications with fewer adverse effects. Increasing evidence indicates that gut microbiome disturbances are involved in the development of T2DM and its complications. This regulation depends on various metabolites produced by gut microbes and their interactions with host organs. TCMs' interventions have demonstrated the ability to modulate the intestinal bacterial microbiota, thereby restoring host homeostasis and ameliorating metabolic disorders. This review delves into the alterations in the gut microbiota and metabolites in T2DM patients and how TCMs treatment regulates the gut microbiota, facilitating the management of T2DM and its complications. Additionally, we also discuss prospective avenues for research on natural products to advance diabetes therapy.

Structural characteristics and biological activities of polysaccharides from barley: a review

Barley (Hordeum vulgare L.) is rich in starch and non-starch polysaccharides (NSPs), especially β-glucan and arabinoxylan. Genotypes and isolation methods may affect their structural characteristics, properties and biological activities. The structure-activity relationships of NSPs in barley have not been paid much attention. This review summarizes the extraction methods, structural characteristics and physicochemical properties of barley polysaccharides. Moreover, the roles of barley β-glucan and arabinoxylan in the immune system, glucose metabolism, regulation of lipid metabolism and absorption of mineral elements are summarized. This review may help in the development of functional products in barley.

Natural Sweetener Glycyrrhetinic Acid Monoglucuronide Improves Glucose Homeostasis in Healthy Mice

Noncaloric or low-caloric sweeteners have become popular worldwide, although debates persist regarding their impact on health. To investigate whether the sweeteners are favorable for glucose homeostasis, our study assessed the effects of glycyrrhetinic acid monoglucuronide (GAMG) and several commonly used sweeteners [glycyrrhetinic acid (GA), stevioside, erythritol, sucralose, and aspartame] on glycometabolism and elucidated the underlying mechanisms. The C57BL/6J male mice were exposed to different sweeteners for 10 weeks, and our results showed that GAMG significantly reduced fasting blood glucose (FBG) levels (FBG-control: 3.81 ± 0.42 mmol/L; FBG-GAMG: 3.37 ± 0.38 mmol/L; p < 0.05) and the blood glucose levels 15 and 30 min after sucrose or maltose loading (p < 0.05). Furthermore, it improved glucose tolerance (p = 0.028) and enhanced insulin sensitivity (p = 0.044), while the other sweeteners had negligible or adverse effects on glucose homeostasis. Subsequent experiments showed that GAMG inhibited α-glucosidases potently (IC50 = 0.879 mg·mL-1), increased three SCFA-producing bacteria and SCFAs levels (p < 0.05), and promoted the gene expression of SCFA receptor GPR43 (p = 0.018). These results suggest that GAMG may regulate blood glucose by inhibiting α-glucosidases and modulating gut microbial SCFAs. Our findings prove that GAMG, beneficial to blood glucose regulation, is a promising natural sweetener for future utilization.

Whole-grain highland barley premade biscuit prepared by hot-extrusion 3D printing: Printability and nutritional assessment

In this study, to explore the possibility of applying whole-grain highland barley (HB) in functional food, HB premade biscuit was created by hot-extrusion 3D printing (HEP) for the first time, and its printability and nutritional functions were evaluated. The rheology results showed 20% (w/w) HB suspension with 9% corn oil addition had better printability due to the formation of a structure with higher elasticity and stronger resistance to deformation. Moreover, the obtained premade biscuit had lower predicted glycemic index (pGI) and starch digestibility. Meanwhile, in vivo experiment results showed it could affect the glycolipid metabolism, ameliorate the high fat diet (HFD)-induced metabolic disorders and maintain the balance of the gut microbial ecology. This could be attributed to the decrease in Firmicutes/Bacteroidetes ratio and the proliferation of propionate-producing probiotics, especially Veilonella, Weissella and Desulfovibrio. Overall, this study could provide basic data and innovative approaches to prepare nutritional whole-grain foods.

Pomelo peel dietary fiber ameliorates alterations in obesity-related features and gut microbiota dysbiosis in mice fed on a high-fat diet

Pomelo peel has abundance of dietary fiber and various biological activities but is often discarded as waste. This study evaluated the biological activities of pomelo peel dietary fiber (PPDF) in preventing obesity and regulating intestinal microbiota in obese mouse model induced using a high-fat diet (HFD). As for the composition, the prepared PPDF contained 89.64% of total dietary fiber, 53.27% of insoluble dietary fiber, and 36.37% of soluble dietary fiber. PPDF treatment significantly reduced weight gain and fat accumulation in the liver and epididymal tissues of obese mice; significantly alleviated HFD-induced dyslipidemia; and restored the levels of triglycerides, low-density lipoprotein-cholesterol, and high-density lipoprotein--cholesterol to control levels, and the PPDF 5% dose restored total cholesterol to the control level. Furthermore, PPDF ameliorated HFD-induced gut microbiota dysbiosis by increasing intestinal microbial diversity, decreasing the Firmicutes/Bacteroidetes ratio, increasing beneficial bacteria (Bifidobacterium, Alloprevotella, and Lactobacillus), and decreasing harmful bacteria (Staphylococcus and Corynebacterium_1). This study provided a new idea to use PPDF as functional food to prevent obesity, alleviate dyslipidemia, or a potential probiotic to ameliorate gut microbiota dysbiosis.

Effects of Qingke β-glucan with different molecular weights on pasting, gelation, and digestive properties of rice starch

This study aimed to investigate the impact of Qingke β-glucan (QBG) concentrations and molecular weights (MWs) on rice starch (RS). With the increasing concentrations and MWs, the pasting properties and gelatinization enthalpy of RS/QBG suspension decreasing was observed by using rheometer and differential thermal scanning analysis, respectively, which was consistent with the results of X-ray diffraction. In Infrared spectrum, QBG combined with leached amylose via hydrogen bonds, thus preventing the reaggregation of RS particles and inhibiting the short-term retrogradation of RS. The results of scanning electron microscopy and confocal laser scanning microscopy suggested that interaction between QBG and RS changed RS microstructure, reduced the leached amylose of the starch, and thus altered RS/QBG digestibility that the digestion rate of RS/QBG decreased with the incrementing QBG MWs at in vitro simulated experiments. These results provide further understanding and expand potential application to starch-based foods.

Genetic Approaches to Increase Arabinoxylan and β-Glucan Content in Wheat

Wheat is one of the three staple crops feeding the world. The demand for wheat is ever increasing as a relatively good source of protein, energy, nutrients, and dietary fiber (DF) when consumed as wholemeal. Arabinoxylan and β-glucan are the major hemicelluloses in the cell walls and dietary fiber in wheat grains. The amount and structure of DF varies between grain tissues. Reducing post-prandial glycemic response as well as intestinal transit time and contribution to increased fecal bulk are only a few benefits of DF consumption. Dietary fiber is fermented in the colon and stimulates growth of beneficial bacteria producing SCFA, considered responsible for a wide range of health benefits, including reducing the risk of heart disease and colon cancer. The recommended daily intake of 25-30 g is met by only few individuals. Cereals cover nearly 40% of fiber in the Western diet. Therefore, wheat is a good target for improving dietary fiber content, as it would increase the fiber intake and simultaneously impact the health of many people. This review reflects the current status of the research on genetics of the two major dietary fiber components, as well as breeding approaches used to improve their quantity and quality in wheat grain.

Insoluble Dietary Fiber from Soybean Residue (Okara) Exerts Anti-Obesity Effects by Promoting Hepatic Mitochondrial Fatty Acid Oxidation

Numerous investigations have shown that insoluble dietary fiber (IDF) has a potentially positive effect on obesity due to a high-fat diet (HFD). Our previous findings based on proteomic data revealed that high-purity IDF from soybean residue (okara) (HPSIDF) prevented obesity by regulating hepatic fatty acid synthesis and degradation pathways, while its intervention mechanism is uncharted. Consequently, the goal of this work is to find out the potential regulatory mechanisms of HPSIDF on hepatic fatty acid oxidation by determining changes in fatty acid oxidation-related enzymes in mitochondria and peroxisomes, the production of oxidation intermediates and final products, the composition and content of fatty acids, and the expression levels of fatty acid oxidation-related proteins in mice fed with HFD. We found that supplementation with HPSIDF significantly ameliorated body weight gain, fat accumulation, dyslipidemia, and hepatic steatosis caused by HFD. Importantly, HPSIDF intervention promotes medium- and long-chain fatty acid oxidation in hepatic mitochondria by improving the contents of acyl-coenzyme A oxidase 1 (ACOX1), malonyl coenzyme A (Malonyl CoA), acetyl coenzyme A synthase (ACS), acetyl coenzyme A carboxylase (ACC), and carnitine palmitoyl transferase-1 (CPT-1). Moreover, HPSIDF effectively regulated the expression levels of proteins involved with hepatic fatty acid β-oxidation. Our study indicated that HPSIDF treatment prevents obesity by promoting hepatic mitochondrial fatty acid oxidation.

Effect of Insoluble Dietary Fiber Extracted from Feijoa (Acca sellowiana (O. Berg) Burret.) Supplementation on Physicochemical and Functional Properties of Wheat Bread

This study aimed to assess the effects of insoluble dietary fiber (IDF) from feijoa supplementation on the physicochemical and functional properties of wheat bread. The results showed that feijoa IDF (FJI) had the typical structures of hydrolysis fiber, polysaccharide functional groups, and crystal structure of cellulose. The gradual increase of FJI levels (from 2 to 8%) in wheat bread resulted in increased total DF, ash, and protein contents, accompanied by a reduction in moisture, carbohydrates, and energy value. The inclusion of FJI in the bread crumb caused a rise in both redness (a*) and yellowness (b*) values while decreasing the brightness (L*) relative to the control specimen. In addition, adding FJI up to 2% significantly increased total phenolic and flavonoid contents and antioxidant activity, as well as flavor score of supplemented bread samples, while additions above 2% resulted in undesirable taste and texture. FJI addition caused higher bile acid, NO^2-, and cholesterol adsorption capacities. Moreover, FJI addition up to 4% significantly reduced glucose adsorption capacities at different in vitro starch digestion intervals. The findings revealed that FJI offers great potential as an ideal functional ingredient in food processing.

Beta-Glucans of Cereals: Functional and Technological Properties

β-glucans are a polymeric dietary fiber characterized by β-(1,3) and β-(1,4) glycosidic bonds between glucose monomers. They are often used as thickeners, stabilizers, and fat substitutes in foods. The functional and technological quality of β-glucans is attributed to their origin/source, molecular weight, and structural properties. In particular, physical treatments such as drying, cooking, freezing, and refrigeration influence their molecular, morphological, and rheological characteristics. In addition to their useful technical qualities, β-glucans are recognized for their numerous beneficial impacts on human health. For this reason, the European Food Safety Authority (EFSA) has provided a positive opinion on health claims such as cholesterol lowering and hypoglycemic properties relating to oats and barley β-glucans. This paper provides insight into the properties of β-glucans and different treatments affecting their characteristics and then reviews the latest research on β-glucans as a functional ingredient for people with type 2 diabetes mellitus (T2DM).

Features of gut microbiota and short-chain fatty acids in patients with first-episode depression and their relationship with the clinical symptoms

Objective

To compare the differences in gut microbiota and short-chain fatty acids (SCFAs; metabolites of gut microbiota) in the serum of patients with first-episode depression and the healthy population and to analyze the relationship between gut microbiota and metabolite SCFAs and the clinical symptoms of major depressive disorder (MDD).

Methods

A total of 45 patients with first-episode depression and 22 healthy volunteers were chosen to complete relevant scale evaluations, and feces samples and venous blood samples were collected. The 16S RNA method was used to analyze the intestinal microflora and the characteristics of serum SCFAs detection by ELISA kit, as well as the intestinal flora, SCFAs content and their correlation with MDD clinical indicators.

Results

The abundance of Akkermansia, Megamonas, Prevotellaceae NK3B31 group, and butyrate-producing bacteria, Lachnospira, Subdoligranulum, Blautia, and Dialister, and acetate-producing bacteria, Streptococcus, in the gut microbiota of the MDD group was lower than that in the control (C) group. The abundance of Parasutterella in the MDD group was higher than that in the C group. Dialister negatively correlated with all measured clinical symptoms (r < 0, P < 0.05). The serum SCFA content in the MDD group was higher than that in the C group, and the content positively correlated with the Hamilton anxiety scale scores (r = 0.584, P < 0.05).

Conclusion

The results demonstrated that the MDD group differed from the C group in terms of gut microbiota and SCFAs in the serum and that the change in certain intestinal bacteria might participate in the pathogenic mechanism of MDD.

The Interplay of Dietary Fibers and Intestinal Microbiota Affects Type 2 Diabetes by Generating Short-Chain Fatty Acids

Foods contain dietary fibers which can be classified into soluble and insoluble forms. The nutritional composition of fast foods is considered unhealthy because it negatively affects the production of short-chain fatty acids (SCFAs). Dietary fiber is resistant to digestive enzymes in the gut, which modulates the anaerobic intestinal microbiota (AIM) and fabricates SCFAs. Acetate, butyrate, and propionate are dominant in the gut and are generated via Wood-Ljungdahl and acrylate pathways. In pancreatic dysfunction, the release of insulin/glucagon is impaired, leading to hyperglycemia. SCFAs enhance insulin sensitivity or secretion, beta-cell function, leptin release, mitochondrial function, and intestinal gluconeogenesis in human organs, which positively affects type 2 diabetes (T2D). Research models have shown that SCFAs either enhance the release of peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) from L-cells (entero-endocrine), or promotes the release of leptin hormone in adipose tissues through G-protein receptors GPR-41 and GPR-43. Dietary fiber is a component that influences the production of SCFAs by AIM, which may have beneficial effects on T2D. This review focuses on the effectiveness of dietary fiber in producing SCFAs in the colon by the AIM as well as the health-promoting effects on T2D.

Effects from supplementary feeding of bamboo powder in perinatal period on farrowing process, serum biochemical indexes, and fecal microbes of sows and offspring piglets

Introduction

This study was conducted to explore the effects of supplementary feeding of bamboo powder on the physical parameters of sows during the perinatal period of 7 days ± in parturition, including farrow duration, serum biochemical indexes, fecal physicochemical indexes, and microbial flora.

Methods

Thirty pregnant sows were randomly divided into three groups: the control group was fed a basal diet, TRE1 group and TRE2 group were fed a basal diet supplemented with 30 g d^-1 and 60 g d^-1 bamboo powder, respectively. Multiple parameters of sows and offspring piglets were determined.

Results

The contents of serum total cholesterol and triglyceride of sows in TRE2 group were significantly lower than those in the control group. The contents of serum malondialdehyde of sows in TRE2 and TRE1 groups were significantly lower than that in control group. The water content of sow feces in TRE2 group was significantly higher than that in control group, and the pH values of sows in TRE2 and TRE1 groups were significantly higher than that in control group. The richness index (Chao) of sow fecal bacterial community in TRE2 group was significantly lower than that of the control group, and the Ace and Sobs indexes tended to be lower than those of the control group. At the phylum level, the relative abundance of Actinobacteriota in the feces of sows in TRE2 group was significantly lower than that of the control group, while that of Fusobacteriota in the feces of suckling piglets in TRE2 group tended to be lower than that of the control group. At the genus level, among the Top10 dominant bacteria, the relative abundance of Tissierella in the feces of sows in TRE2 group was significantly lower than that of the control group while that of Fusobacterium in the feces of suckling piglets in TRE2 group tended to be lower than that of the control group. The relative abundance of Clostridium_sensu_stricto_1, Terrisporobacter, Turicibacter, and Tissierella in the feces of sows in TRE2 group was significantly lower than that of TRE1 group (p < 0.05), while Lactobacillus tended to be higher than that of TRE1 group (p < 0.10).

Discussion

The results suggested that supplementary feeding 60 g d^-1 bamboo powder could increase the water content in the feces of sows, reduce the oxidative damage, and tend to reduce the relative abundance of opportunistic pathogenic Fusobacterium for suckling piglets, while it reduced the fecal microbial diversity of sows.

Polygonatum sibiricum saponin Exerts Beneficial Hypoglycemic Effects in Type 2 Diabetes Mice by Improving Hepatic Insulin Resistance and Glycogen Synthesis-Related Proteins

Type 2 diabetes mellitus (T2DM) is a systemic metabolic disorder characterized by insulin deficiency and insulin resistance. Recently, it has become a significant threat to public health. Polygonatum sibiricum saponin (PSS) has potential hypoglycemic effects, but its specific mechanism needs further study. In this study, PSS significantly decreased the level of blood glucose, water intake, and the organ index in diabetic mice. Meanwhile, PSS effectively reduced the content of total triglyceride (TG), total cholesterol (TCHO), low-density lipoprotein cholesterol (LDL-C), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) in the blood, and increased the content of high-density lipoprotein cholesterol (HDL-C). This suggests that PSS could reduce the content of blood lipids and initially improve the damage of hepatocytes. We found that PSS alleviated hepatic insulin resistance, repaired islet beta cells, and enabled insulin to play its biological role normally. It also improved oral glucose tolerance and abated serum lipopolysaccharide (LPS) and glycosylated hemoglobin (HbA1c) levels in T2DM mice. Furthermore, studies have found that PSS increased the content of phosphorylated protein kinase B (AKT), thereby promoting the effect of glucose transporter 4 (GLUT-4), and activating glycogen synthase kinase 3beta (GSK-3β) and glycogen synthase (GS) proteins to promote hepatic glycogen synthesis. Finally, we found that PSS could promote the growth of beneficial bacteria such as Bifidobacterium and Lactobacillus, reduce the growth of harmful bacteria such as Enterococcus and Enterobacter, and preliminarily improve the composition of important bacteria in the intestine. These studies indicate that PSS has an excellent hypoglycemic effect, which provides a potential new treatment for T2DM and guidance for more in-depth research.

Chemical composition, glycaemic index, and antidiabetic property of analogue rice made from composite tubers, germinated legumes, and cereal flours

The dependence on rice as a source of carbohydrates in Indonesia is among the highest in Asia. Innovations to develop products that can be used as a carbohydrate source, and have functional values beneficial to health are currently needed. The present work thus aimed to determine the chemical composition, glycaemic index, and antidiabetic property of three analogue rice types. The formulation of three types of analogue rice was done by combining natural tuber flour, modified tuber flour, germinated cereals, and germinated legumes. The glycaemic index was assessed using experimental animal. The antidiabetic properties of three types of analogue rice were assessed by food efficiency ratio, glucose profile, lipid profile, and atherogenic index. Results showed that analogue rice had high dietary fibre, resistant starch, and protein, and low fat and carbohydrate. The three types of analogue rice were classified as low glycaemic index based on glycaemic response tests. The glycaemic index of analogue rice I, II, and III were 41.23 ± 3.39, 42.55 ± 3.21, and 40.19 ± 3.34, respectively. The ability of analogue rice to decrease glucose, triglycerides, total cholesterol, low-density lipoprotein, atherogenic index; and increase high-density lipoprotein in diabetic mice was affected by its low glycaemic index and chemical composition benefits. The ability to improve the characteristics of glucose and lipids should support the development of analogue rice as a functional food.

Germinated Millet (Pennisetum glaucum (L.) R. Br.) Flour Improved the Gut Function and Its Microbiota Composition in Rats Fed with High-Fat High-Fructose Diet

Germinated millet (Pennisetum glaucum (L.) R. Br.) is a source of phenolic compounds that has potential prebiotic action. This study aims at evaluating the action of germinated pearl millet on gut function and its microbiota composition in Wistar rats fed with a high-fat high-fructose (HFHF) diet. In the first stage, lasting eight weeks, the experiment consisted of two groups: AIN-93M (n = 10) and HFHF group (n = 20). In the second stage, which lasted ten weeks, the animals of the AIN-93M group (n = 10) were kept, while the HFHF group was dismembered into HFHF (HFHF diet, n = 10) and HFHF + millet (HFHF added 28.6% of germinated millet flour, n = 10) groups. After the 18th week, the urine of the animals was collected for the analysis of lactulose and mannitol intestinal permeability by urinary excretion. The histomorphometry was analyzed on the proximal colon and the fecal pH, concentration of short-chain fatty acids (SCFA), and sequencing of microbiota were performed in cecum content. The Mothur v.1.44.3 software was used for data analysis of sequencing. Alpha diversity was estimated by Chao1, Shannon, and Simpson indexes. Beta diversity was assessed by PCoA (Principal Coordinate Analysis). The functional predictive analysis was performed with PICRUSt2 software (version 2.1.2-b). Functional traits attributed to normalized OTU abundance were determined by the Kyoto Encyclopedia of Genes and Genomes (KEGG). In the results, germinated millet flour reduced Oscillibacter genus and Desulfobacterota phylum, while increasing the Eggerthellaceae family. Furthermore, germinated millet flour: increased beta diversity, cecum weight, and cecum/body weight ratio; improved gut histological parameters by increasing the depth and thickness of the crypt and the goblet cell count (p < 0.05); reduced (p < 0.05) the fecal pH and mannitol urinary excretion; increased (p < 0.05) the propionate short-chain fatty acid concentration. Thus, germinated millet has the potential to improve the composition of gut microbiota and the intestinal function of rats fed with an HFHF diet.

Effect of acid hydrolysis on the structural and antioxidant characteristics of β-glucan extracted from Qingke (Tibetan hulless barley)

In this study, we explored the effect of acid hydrolysis on the molecular, structural, rheological, thermal, and antioxidant characteristics of Qingke β-glucan. The acid hydrolysis reduced the molecular weights of β-glucans from 510 to 155 KDa. The results of the structural analysis by nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction, and fourier transforms infrared (FTIR) spectroscopy indicated that acid hydrolysis did not change the primary functional groups of β-glucans. The rheological behavior of β-glucan without and with acid hydrolysis can be described as pseudoplastic and Newtonian, respectively. The DSC curves of the β-glucans with high molecular weights showed the highest transition temperature. The 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity and the reducing power of soluble β-glucans in Qingke showed a dose-dependent pattern. Meanwhile, the antioxidant activities of Qingke β-glucan of different molecular weights were similar. This study demostrated that the acid hydrolysis almost have no effect on antioxidant activity of Qingke β-glucans.

Effects of Additional Dietary Fiber Supplements on Pregnant Women with Gestational Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Studies

The efficacy of different types and doses of dietary fiber supplementation in the treatment of gestational diabetes (GDM) remains controversial. The purpose of this study is to investigate the effect of dietary fiber on blood glucose control in pregnant women with gestational diabetes mellitus, and further observe the effect on their blood lipids and pregnancy outcomes. We searched on Web of Science, PubMed, Embase, Scopus, and Cochrane, and included several articles on additional fortification with dietary fiber for gestational diabetes interventions. This meta-analysis included 8 trials. We found that additional dietary fiber supplements significantly reduced fasting glucose (Hedges’g = −0.3; 95% CI [−0.49, −0.1]), two-hour postprandial glucose (Hedges’g = −0.69; 95% CI [−0.88, −0.51]), glycated hemoglobin (Hedges’g = −0.5; 95% CI [−0.68, −0.31]), TC (Hedges’g = −0.44; 95% CI [−0.69, −0.19]), TG (Hedges’g = −0.3; 95% CI [−0.4, −0.2]) and LDL-C (Hedges’g = −0.48; 95% CI [−0.63, −0.33]). It also significantly reduced preterm delivery (Hedges’g = 0.4, 95% CI [0.19~0.84]), cesarean delivery (Hedges’g = 0.6; 95% CI [0.37~0.97]), fetal distress (Hedges’g = 0.51; 95% CI [0.22~1.19]), and neonatal weight (Hedges’g = −0.17; 95% CI [−0.27~−0.07]). In a subgroup analysis comparing dietary fiber type and dose, insoluble dietary fiber was more effective than soluble dietary fiber in reducing fasting glucose (Hedges’g = −0.44; 95% CI [−0.52, −0.35]). ≥12 g fiber per day may be more effective in improving glycemic lipid and pregnancy outcomes than <12 g/day, but the difference was not statistically significant. In conclusion, our meta-analysis showed that dietary fiber supplementation significantly improved glycolipid metabolism and pregnancy outcomes in gestational diabetes. Dietary fiber may be considered adjunctive therapy for gestational diabetes, and an additional supplement with insoluble dietary fiber is more recommended for those with poor fasting glucose. However, more high-quality studies are needed on the further effect of fiber type and the dose-effect relationship.

Insoluble Fiber in Barley Leaf Attenuates Hyperuricemic Nephropathy by Modulating Gut Microbiota and Short-Chain Fatty Acids

Hyperuricemia (HUA), characterized by abnormal serum uric acid (UA) levels, is recognized as an important risk factor for hyperuricemic nephropathy (HN), which is strongly linked to gut microbiota. This study investigated the protective effects and regulatory mechanisms of insoluble fiber from barley leaves (BL) against HN, induced by adenine (Ad) and potassium oxonate (PO). The results showed that BL dramatically reduced the levels of serum UA and creatinine (CR) and alleviated renal injury and fibrosis. Moreover, BL modulated oxidative stress and downregulated the expression of urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) in the kidneys of mice with HN. In addition, the 16S rRNA sequence data showed that BL also increased the relative abundance of short-chain fatty acids (SCFAs)-producing bacteria, including Bacteroides, Alloprevotella, and Eisenbergiella. Besides, BL treatment also increased SCFAs levels. Of interest, the application of SCFAs in hyperuricemic mice effectively reduced their serum UA. Furthermore, SCFAs dose-dependently inhibited URAT1 and GLUT9 in vitro and potently interacted with URAT1 and GLUT9 in the docking analysis. When taken together, our results indicate that BL and its metabolite SCFAs may be potential candidates for relieving HUA or HN.

Short-chain fatty acid: An updated review on signaling, metabolism, and therapeutic effects

Fatty acids are good energy sources (9 kcal per gram) that aerobic tissues can use except for the brain (glucose is an alternative source). Apart from the energy source, fatty acids are necessary for cell signaling, learning-related memory, modulating gene expression, and functioning as cytokine precursors. Short-chain fatty acids (SCFAs) are saturated fatty acids arranged as a straight chain consisting minimum of 6 carbon atoms. SCFAs possess various beneficial effects like improving metabolic function, inhibiting insulin resistance, and ameliorating immune dysfunction. In this review, we discussed the biogenesis, absorption, and transport of SCFA. SCFAs can act as signaling molecules by stimulating G protein-coupled receptors (GPCRs) and suppressing histone deacetylases (HDACs). The role of SCFA on glucose metabolism, fatty acid metabolism, and its effect on the immune system is also reviewed with updated details. SCFA possess anticancer, anti-diabetic, and hepatoprotective effects. Additionally, the association of protective effects of SCFA against brain-related diseases, kidney diseases, cardiovascular damage, and inflammatory bowel diseases were also reviewed. Nanotherapy is a branch of nanotechnology that employs nanoparticles at the nanoscale level to treat various ailments with enhanced drug stability, solubility, and minimal side effects. The SCFA functions as drug carriers, and nanoparticles were also discussed. Still, much research was not focused on this area. SCFA functions in host gene expression through inhibition of HDAC inhibition. However, the study has to be focused on the molecular mechanism of SCFA against various diseases that still need to be investigated.

Oat β-glucan and L-arabinose synergistically ameliorate glucose uptake in insulin-resistant HepG2 cells and exert anti-diabetic activity via activation of the PI3K/AKT pathway in db/db mice

Oat β-glucan (OBG) and L-arabinose (LA) have exhibited positive effects on diabetes and its complications. However, it is unclear whether OBG and LA have a synergistic effect. We investigated the effect of variable compositions (OBG : LA = 1 : 1, 1 : 2, 1 : 4,1 : 6, 1 : 8, 1 : 10, 2 : 1, 4 : 1, 6 : 1, 8 : 1, 10 : 1) on glucose uptake in IR-HepG2 cells induced by dexamethasone (DEX) to find out the optimal composition showing synergistic effects. Furthermore, this study evaluated the anti-diabetic activity of the optimal composition in db/db mice. In vitro, the OBG : LA = 1 : 1 group showed the strongest synergistic effects among the varied compositions, outperforming OBG and LA alone. In vivo, there were more beneficial effects in the OBG : LA = 1 : 1 group compared with the OBG and LA single-dosing groups. OBG : LA = 1 : 1 supplementation markedly decreased the levels of fasting blood glucose (FBG) and insulin (INS) in serum, improved glucose tolerance and insulin sensitivity, lowered blood lipid levels, and reduced liver lipid accumulation. Moreover, the western blot results indicated that the OBG : LA = 1 : 1 group up-regulated the protein expression of glucose transporter-4 (GLUT4), phosphatidylinositol 3-kinase (PI3K), and phospho-protein kinase B (p-AKT), while down-regulating the protein expression of phospho-phosphorylated insulin receptor substrate-1 (p-IRS1) to enhance insulin transduction in liver tissues. These findings suggest that OBG : LA = 1 : 1 synergistically ameliorated glucose metabolism disorders and alleviated insulin resistance by promoting the PI3K/AKT pathway in the liver.

Chemical features and biological functions of water-insoluble dietary fiber in plant-based foods

Insoluble dietary fiber (IDF) is a nutritional component constituting the building block of plant cell walls. Our understanding of the role of IDF in plant-based foods has advanced dramatically in recent years. In this Review, we summarize research progress on the subtypes, structure, analysis, and extraction methods of IDF. The impact of different food processing methods on the properties of IDF is discussed. The role of gut microbiota in the health benefits of IDF is introduced. This review provides a better understanding of the chemical features and biological functions of IDF, which may promote the future application of IDF in functional food products. Further investigation of the mechanisms underlying the health benefits of IDF enables the development of effective strategies for the prevention and treatment of human diseases.

Insoluble and Soluble Dietary Fibers from Kiwifruit (Actinidia deliciosa) Modify Gut Microbiota to Alleviate High-Fat Diet and Streptozotocin-Induced TYPE 2 Diabetes in Rats

This study aims to examine the anti-diabetic properties of insoluble and soluble dietary fibers from kiwifruit (KIDF and KSDF) in rats with type 2 diabetes mellitus (T2DM) resulting from a high-fat diet (HFD) and streptozotocin (STZ). Both KIDF and KSDF treatments for four weeks remarkably decreased body weight and increased satiety. In addition, the blood glucose level and circulatory lipopolysaccharide (LPS) content were decreased, while the insulin resistance, inflammatory status, and lipid profiles improved. These anti-diabetic effects might be related to the regulation of gut microbiota and increased SCFA content. The key microbial communities of KIDF and KSDF were different. Furthermore, the KIDF treatment increased the level of total SCFAs and isobutyric acid, while KSDF increased the levels of total SCFAs and butyric acid. The association between critical species and SCFA and between SCFA and biochemical parameters indicated that the mechanisms of KIDF and KSDF on T2DM might be different.

Compound dietary fiber and high-grade protein diet improves glycemic control and ameliorates diabetes and its comorbidities through remodeling the gut microbiota in mice

Dietary intervention with a low glycemic index and full nutritional support is emerging as an effective strategy for diabetes management. Here, we found that the treatment of a novel compound dietary fiber and high-grade protein diet (CFP) improved glycemic control and insulin resistance in streptozotocin-induced diabetic mice, with a similar effect to liraglutide. In addition, CFP treatment ameliorated diabetes-related metabolic syndromes, such as hyperlipidemia, hepatic lipid accumulation and adipogenesis, systemic inflammation, and diabetes-related kidney damage. These results were greatly associated with enhanced gut barrier function and altered gut microbiota composition and function, especially those bacteria, microbial functions, and metabolites related to amino acid metabolism. Importantly, no adverse effect of CFP was found in our study, and CFP exerted a wider arrange of protection against diabetes than liraglutide. Thereby, fortification with balanced dietary fiber and high-grade protein, like CFP, might be an effective strategy for the management and treatment of diabetes.

The potential mechanisms of bergamot-derived dietary fiber alleviating high-fat diet-induced hyperlipidemia and obesity in rats

This study is aimed to investigate the health-associated benefits of bergamot-dietary fibers (DFs) with a special emphasis on weight loss and lipid-lowering effects, as well as the potential mechanisms involved. The feeding experiment of Sprague-Dawley (SD) rats for 6 weeks showed that DFs had dose-dependent regulatory effects against metabolic syndrome and they controlled obesity by slowing down the rate of weight growth, and reduced body mass index (BMI) and Lee's index without affecting appetite. Furthermore, DFs inhibited increment in TG, TC, LDL-C levels and AI index caused by a high-fat diet, and improved the pathological abnormality of the liver. Western blot results showed that DFs significantly up-regulated the protein expression levels of LXRα and CYP7A1, and down-regulated the levels of SREBP-1c, FAS, ACC and SREBP-2 in the liver. QRT-PCR results showed that DFs up-regulated PGC-1α, PRDM16, UCP-1, and PPARγ in brown adipose tissue. These results suggest that DFs played an effective role in reducing weight and lipids levels by promoting the decomposition and transport of lipids in liver, increasing the energy consumption of brown adipose tissue. DFs intervention reduced the difference in the intestinal microflora between rats fed with a normal diet and those fed with a high-fat diet. Soluble dietary fiber (SDF) and total dietary fiber (TDF) showed better weight loss and hypolipidemic potential compared to insoluble dietary fiber (IDF) at the same dose. In conclusion, bergamot-derived DFs demonstrated the potential to lower blood cholesterol and body weight and could be used to develop novel functional foods for the prevention or treatment of obesity and hyperlipidemia.

Recent Developments in Fermented Cereals on Nutritional Constituents and Potential Health Benefits

Fermentation is one of the most economical and safe methods to improve the nutritional value, sensory quality and functional characteristics of raw materials, and it is also an important method for cereal processing. This paper reviews the effects of microbial fermentation on cereals, focusing on their nutritional value and health benefits, including the effects of fermentation on the protein, starch, phenolic compounds contents, and other nutrient components of cereals. The bioactive compounds produced by fermented cereals have positive effects on health regulation. Finally, the future market development of fermented cereal products is summarized and prospected.

Evaluation of Nutritional Components, Phenolic Composition, and Antioxidant Capacity of Highland Barley with Different Grain Colors on the Qinghai Tibet Plateau

The nutritional composition, polyphenol and anthocyanin composition, and antioxidant capacity of 52 colored highland barley were evaluated. The results showed that the protein content of highland barley in the black group was the highest, the total starch and fat contents in the blue group were the highest, the amylose content in the purple group was quite high, the fiber content in the yellow group was quite high, and the β-glucan content of the dark highland barley (purple, blue and black) was quite high. The polyphenol content and its antioxidant capacity in the black group were the highest, while the anthocyanin content and its antioxidant capacity in the purple highland barley were the highest. Ten types of monomeric phenolic substances were the main contributors to DPPH, ABTS, and FRAP antioxidant capacity. All varieties could be divided into four categories according to nutrition or function. The grain color could not be used as an absolute index to evaluate the quality of highland barley, and the important influence of variety on the quality of highland barley also needed to be considered. In actual production, suitable raw materials must be selected according to the processing purpose and variety characteristics of highland barley.

Gut microbiota-derived metabolites as key actors in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is one of the most risk factors threatening human health. Although genetic and environmental factors contribute to the development of T2DM, gut microbiota has also been found to be involved. Gut microbiota-derived metabolites are a key factor in host-microbe crosstalk, and have been revealed to play a central role in the physiology and physiopathology of T2DM. In this review, we provide a timely and comprehensive summary of the microbial metabolites that are protective or causative for T2DM, including some amino acids-derived metabolites, short-chain fatty acids, trimethylamine N-oxide, and bile acids. The mechanisms by which metabolites affect T2DM have been elaborated. Knowing more about these processes will increase our understanding of the causal relationship between gut microbiota and T2DM. Moreover, some frontier therapies that target gut microbes and their metabolites to improve T2DM, including dietary intervention, fecal microbiota transplantation, probiotics, prebiotics or synbiotics intervention, and drugging microbial metabolism, have been critically discussed. This review may provide novel insights for the development of targeted and personalized treatments for T2DM based on gut microbial metabolites. More high-quality clinical trials are needed to accelerate the clinical translation of gut-targeted therapies for T2DM.

Antidiabetic Effects of Bifidobacterium longum subsp. longum BL21 through Regulating Gut Microbiota Structure in Type 2 Diabetic Mice

Bifidobacterium longum subsp. longum BL21 (BL21) possess hypoglycemic activity, but its anti-diabetic mechanism has rarely been illustrated. In the present work, the effect of BL21 on type 2 diabetes mellitus...

Isolation, Structural, Functional, and Bioactive Properties of Cereal Arabinoxylan─A Critical Review

Arabinoxylans (AXs) are widely distributed in various cereal grains, such as wheat, corn, rye, barley, rice, and oat. The AX molecule contains a linear (1,4)-β-D-xylp backbone substituted by α-L-araf units and occasionally t-xylp and t-glcpA through α-(1,2) and/or α-(1,3) glycosidic linkages. Arabinoxylan shows diversified functional and bioactive properties, influenced by their molecular mass, branching degree, ferulic acid (FA) content, and the substitution position and chain length of the side chains. This Review summarizes the extraction methods for various cereal sources, compares their structural features and functional/bioactive properties, and highlights the established structure-function/bioactivity relationships, intending to explore the potential functions of AXs and their industrial applications.

Nutritional composition, antioxidant activity, volatile compounds, and stability properties of sweet potato residues fermented with selected lactic acid bacteria and bifidobacteria

The effects of four kinds of lactic acid bacteria (LAB) and one bifidobacteria on nutritional composition, antioxidant activity, volatile compounds and stability properties of fermented sweet potato residues (SPR) were investigated. The soluble dietary fiber (12.92-16.63 g/100 g DW), total polyphenols content (90.51-97.35 mg/100 g DW), organic acids, and stability of SPR were increased after fermentation. The DPPH radical scavenging capacity (39.49-62.04 mg AAE/100 g DW) and ferric reducing antioxidant power (47.14-71.87 mg TE/100 g DW) were also increased, of which SPR fermented with Lacticaseibacillus rhamnosus CICC 23119 exhibited the highest values. Meanwhile, the anti-nutritional compound (oxalic acid) was decreased from 0.46 to 0.08-0.30 mg/g DW. Also, the fermented SPR exhibited different flavors compared with SPR, due to the production of acids especially antiseptic hexanoic acid and sorbic acid. Therefore, these results can provide a theoretical basis for the high-value utilization of SPR.

Preparation and characterization of soybean insoluble dietary fiber and its prebiotic effect on dyslipidemia and hepatic steatosis in high fat-fed C57BL/6J mice

The potential benefits of insoluble dietary fiber (IDF) in the regulation of lipid metabolism have been reported in large prospective cohort studies although the molecular regulatory mechanism is still unclear. Okara is a by-product obtained during soybean processing for soy milk and soybean curd (tofu), which is rarely utilized and can be a cheap potential dietary fiber (DF) resource. In this study, the structure and physicochemical properties of insoluble dietary fiber (SIDF) extracted from okara were characterized, and the prebiotic effects on fat metabolism were investigated in vivo. The results showed that the main monosaccharides of SIDF (90.50%) identified were galactose, arabinose, xylose, rhamnose and glucose. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analyses suggested that SIDF had a loose and porous structure, polysaccharide functional groups, and a typical crystalline cellulose I structure. In addition, SIDF had ideal oil-adsorption capacity (OAC; 7.95 g g-1) and significantly improved cholesterol adsorption (11.14 mg g-1) at pH 7.0. In vivo, IDF supplementation reduced the serum lipid levels and inhibited hepatic fat accumulation. Additionally, SIDF administration improved hepatic steatosis by stimulating lipolysis via upregulation of PPARα, CYP4a10 and CPT1a. This is the first systematic study on the composition, structure, physicochemical properties, adsorption function and biological effects of SIDF. The above results show that SIDF could be used as an ideal functional ingredient in food processing as well as play a positive role in improving the added value of okara and promoting its comprehensive utilization.

Effect of soybean insoluble dietary fiber on prevention of obesity in high-fat diet fed mice via regulation of the gut microbiota

Increasing evidence has shown that the gut microbiota plays an important role in preventing obesity; however, the mechanism by which insoluble dietary fiber (IDF) prevents high-fat diet (HFD)-induced obesity remains unclear. This study aimed to investigate the effect of SIDF on obesity in HFD mice and determine the mechanism by which it prevents obesity through regulating the gut microbiota. Soybean insoluble dietary fiber (SIDF) was used as an intervention in HFD mice for 20 weeks. The results showed that SIDF significantly reduced the body weight (BW), fat index, total cholesterol, triglyceride, and low-density lipoprotein cholesterol while increasing the content of high-density lipoprotein cholesterol in HFD mice. SIDF intervention was also beneficial for the reduction of liver lipid content and fatty droplets in mice. Furthermore, SIDF intervention improved the gut microbiota composition by increasing the relative abundance of potentially beneficial bacteria (such as Lactobacillales [order], Lactobacillus [genus], Lachnospirace_Nk4A136_group [genus]), and reduced the relative abundance of potentially harmful bacteria (such as Lachnospiraceae [family] and Bacteroides_acidifaciens [species]), which correlated with obesity (at least p < 0.05 in all instances). Finally, SIDF was fermented by related beneficial bacteria, which increased the content of the short-chain fatty acids (SCFAs), and promoted the secretion of satiety hormones. In conclusion, SIDF intervention could prevent obesity in HFD mice by modulating the gut microbiota composition. Hence, SIDF may be used as a potential ingredient in functional foods.

Interventional effect of dietary fiber on blood glucose and pregnancy outcomes in patients with gestational diabetes mellitus

To investigate the effect of dietary fiber on blood glucose and pregnancy outcomes in patients with gestational diabetes mellitus (GDM). One hundred and twelve patients with GDM in the second trimester of pregnancy were recruited from Women's Hospital, Zhejiang University School of Medicine. Patients were randomized into two groups with 56 in each group: the control group received basic nutrition support; while the dietary fiber group were given additional dietary fiber ( total dietary fiber per day) before meals in addition to basic nutrition support. Intervention for all cases lasted for 8 weeks. Fasting blood glucose and postprandial blood glucose (2 h BG) were measured every week, and oral glucose tolerance test (OGTT) was performed at 42 d postpartum to evaluate the glycemic outcomes. Perinatal outcomes were recorded. The dietary fiber intervention markedly improved 2 h BG in patients with GDM and significantly elevated the glucose compliance rate from the 3rd to 8th week compared to the control group ( <0.05 or <0.01). OGTT 2 h glucose and the incidence of impaired glucose tolerance in the dietary fiber group were significantly lower than those in the control group, while the glucose compliance rate was significantly higher than that in the control group (all <0.01). Moreover, the rates of adverse perinatal outcomes, such as premature rupture of membranes and neonatal hyperbilirubinemia were declined in the dietary fiber group (<0.05 or <0.01). Dietary fiber intervention can ameliorate hyperglycemia in GDM patients, improve perinatal outcomes and reduce the incidence of postpartum impaired glucose tolerance.

Chimonanthus nitens Oliv. essential oil mitigates lipopolysaccharide-induced acute lung injury in rats

This study aimed to evaluate the effect of Chimonanthus nitens Oliv. essential oil (named CEO) on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rats. In the present study, 21 compounds were characterized in CEO by gas chromatography-mass spectrometry analysis. Furthermore, animal data suggested that CEO could protect rats against ALI, as evidence by increasing white blood cell count, reducing immune organ index and improving lung histopathological changes in rats subjected to LPS. Reduction of the levels of IL-1β was also shown during CEO-triggering lung protection in rats. Meanwhile, these protective effects of CEO were accompanied by the attenuation of lipid oxidation, and elevation of antioxidant enzymes, suggesting that enhancement of antioxidant defense was linked to its lung protection. Moreover, a combination with CEO and LPS significantly elevated short-chain fatty acids (SCFAs) compared with LPS alone via increasing propionic, i-butyric, butyric and i-valeric acid on LPS-induced ALI in rats. Therefore, our findings indicated that CEO could alleviate LPS-caused ALI in rats by controlling aberrant inflammation, correcting the redox system, and modulating SCFAs in rats.

L-Theanine affects intestinal mucosal immunity by regulating short-chain fatty acid metabolism under dietary fiber feeding

To investigate the effects of l-Theanine (LTA) on intestinal mucosal immunity and the regulation of short-chain fatty acid (SCFA) metabolism under dietary fiber feeding, a 28-day feeding experiment was performed in Sprague-Dawley rats. The results show that LTA increased the proportion of Prevotella, Lachnospira, and Ruminococcus while increasing the total SCFA, acetic acid, propionic acid, and butyric acid contents in the feces. LTA also increased IgA, IgE, and IgG levels in the ileum, and increased villi height and crypt depth. Moreover, LTA upregulated the mRNA and protein expression of acetyl-CoA carboxylase 1, sterol element-binding protein 1c, fatty acid synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase in the liver, while downregulating the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon. Our study suggests that LTA can affect intestinal mucosal immunity by regulating SCFA metabolism under dietary fiber feeding.

The Effects of Erchen Decoction on Gut Microbiota and Lipid Metabolism Disorders in Zucker Diabetic Fatty Rats

Obesity is a chronic metabolic disease caused by genetic and environmental factors that has become a serious global health problem. There is evidence that gut microbiota is closely related to the occurrence and development of obesity. Erchen Decoction (ECD), a traditional Chinese medicine, has been widely used for clinical treatment and basic research of obesity and related metabolic diseases in recent years. It can significantly improve insulin resistance (IR) and lipid metabolism disorders. However, there is no microbiological study on its metabolic regulation. In this study, we investigated the effects of ECD on obesity, especially lipid metabolism and the composition and function of gut microbiota in Zucker diabetic fatty (ZDF) rats, and explored the correlation between the biomarkers of gut microbiota and metabolite and host phenotype. The results showed that ECD could reduce body weight, improve IR and lipid metabolism, and reduce the concentration of free fatty acids (FFA) released from white adipose tissue (WAT) due to excessive lipolysis by interfering with the insulin receptor substrate 1 (IRS1)/protein kinase B (AKT)/protein kinase A (PKA)/hormone-sensitive triglyceride lipase (HSL) signaling pathway in ZDF rats. Additionally, ECD gradually adjusted the overall structure of changed gut microbiota, reversed the relative abundance of six genera, and changed the function of gut microbiota by reducing the content of propionic acid, a metabolite of gut microbiota, in ZDF rats. A potentially close relationship between biomarkers, especially Prevotella, Blautia, and Holdemania, propionic acid and host phenotypes were demonstrated through correlation analysis. The results suggested that the beneficial effects of ECD on obesity, especially lipid metabolism disorders, are related to the regulation of gut microbiota in ZDF rats. This provides a basis for further research on the mechanism and clinical application of ECD to improve obesity via gut microbiota.

Gut modulation based anti-diabetic effects of carboxymethylated wheat bran dietary fiber in high-fat diet/streptozotocin-induced diabetic mice and their potential mechanisms

We explored the effect of carboxymethylated wheat bran dietary fibers (DFs) on mice with type 2 diabetes (T2D) (induced by HFD combined with STZ) and their possible hypoglycemic mechanism. After feeding the diabetic mice with modified DFs for four weeks, the DFs had lipid lowering and anti-hyperglycemic effect, via increasing the levels of insulin, GLP-1, PYY, and SCFAs in diabetic mice, and improving the histopathology of liver and pancreas. qRT-PCR results showed that the intake of DFs up-regulated the expression levels of G6Pase and Prkce, and down regulated the expression levels of Glut2 and InsR in the liver of diabetic mice. It is suggested that DFs may play a role by inhibiting 1,2-DAG-PKCε pathway, improving insulin receptor activity and insulin signal transduction. 16 S rDNA high-throughput sequencing results showed that the DFs significantly improved the relative abundance of Akkermansia muciniphila, increased the diversity of gut microbiota and reduced the ratio of Firmicutes to Bacteroidetes, thus promoting the hypoglycemic and hypolipidemic effect on diabetic mice. Our study can foster the further understanding of the gut modulatory biomarkers and related metabolites, and may extend the basis for DFs as a potential dietary intervention to prevent or treat the T2D.

Isolation, Physicochemical Properties, and Structural Characteristics of Arabinoxylan from Hull-Less Barley

Arabinoxylan (HBAX-60) was fractioned from alkaline-extracted arabinoxylan (HBAX) in the whole grain of hull-less barley (Hordeum vulgare L. var. nudum Hook. f. Poaceae) by 60% ethanol precipitation, which was studied for physicochemical properties and structure elucidation. Highly purified HBAX-60 mainly composed of arabinose (40.7%) and xylose (59.3%) was created. The methylation and NMR analysis of HBAX-60 indicated that a low-branched β-(1→4)-linked xylan backbone possessed un-substituted (1,4-linked β-Xylp, 36.2%), mono-substituted (β-1,3,4-linked Xylp, 5.9%), and di-substituted (1,2,3,4-linked β-Xylp, 12.1%) xylose units as the main chains, though other residues (α-Araf-(1→, β-Xylp-(1→, α-Araf-(1→3)-α-Araf-(1→ or β-Xylp-(1→3)-α-Araf-(1→) were also determined. Additionally, HBAX-60 exhibited random coil conformation in a 0.1 M NaNO3 solution. This work provides the properties and structural basis of the hull-less barley-derived arabinoxylan, which facilitates further research for exploring the structure-function relationship and application of arabinoxylan from hull-less barley.

Consumption of Sourdough Breads Improves Postprandial Glucose Response and Produces Sourdough-Specific Effects on Biochemical and Inflammatory Parameters and Mineral Absorption

To evaluate responses to different sourdough breads, six groups of rats were fed a conventional refined wheat bread with no sourdough content (C_WhB); a leavened spelt bread baked with Rebola sourdough (Re_SpB); a durum wheat bread with Rebola sourdough (Re_DuB); or a multigrain bread leavened with Rebola (Re_MGB), Carla (Ca_MGB), or San Francisco sourdough (SF_MGB). Compared to C_WhB-fed rats, Re_SpB-, Re_DuB-, and Re_MGB-fed animals showed lower postprandial blood glucose levels, whereas SF_MGB-fed rats displayed a decreased postprandial blood insulin response and glucose and insulin products. The 3 week intake of Ca_MGB decreased blood triacylglycerols and the relative apparent absorption (RAA) of Fe²⁺, Cu²⁺, and Zn²⁺, whereas Re_MGB-fed animals showed lower serum levels of the MCP-1 inflammatory marker and decreased the Fe RAA. The 3 week consumption of the multigrain bread produced sourdough-specific effects. Thus, Re_MGB-fed animals displayed higher insulin concentrations than Ca_MGB- and SF_MGB-fed rats and decreased blood MCP-1 levels compared to those of Ca_MGB-fed animals. In addition, Ca_MGB-fed rats showed lower serum triacylglycerol concentrations than those of Re_MGB- and SF_MGB-fed animals, whereas SF_MGB-fed rats displayed higher RAA values of Ca²⁺, Cu²⁺, Fe²⁺, Mg²⁺, and Zn²⁺ than their Re_MGB and Ca_MGB counterparts. These sourdough-specific effects could be related to changes in the contents of sugars and organic acids, acidity, microbial composition, and proteolytic activity among sourdoughs. Hence, the consumption of sourdough breads improved postprandial blood glucose and insulin responses and produced sourdough-specific effects on RAA and serum insulin and triacylglycerol and MCP-1 levels in rats, showing that SF_MGB has the most promising beneficial effects.