Effect of single or combined administration of resistant starch and chitosan oligosaccharides on insulin resistance in rats fed with a high-fat diet

Chitooligosaccharide enhances plant resistance to P. nicotianae via sugar homeostasis and microorganism assembly

Phytophthora nicotianae is a highly destructive soil-borne plant pathogen that leads to significant economic losses in agriculture. Chitooligosaccharides (COS) are popular biostimulant which can promote plant growth and responses to biotic and abiotic stresses. However, the role of COS in resisting the black-shank disease (BSD, caused by P. nicotianae) through regulating plant root exudates and rhizosphere microecology remains unclear. An integrative analysis, based on the transcriptome analysis, root exudate metabolome, and biochemical tests, revealed the secretion of more sugar-related differential metabolites and differential gene expressions expressed under COS treatment during the disease resistance response. Furthermore, increased accumulation of trehalose and trehalose 6-phosphate as well as increased activity of trehalose 6-phosphate synthase was observed under COS treatment after inoculation with P. nicotianae. Additionally, sucrose and glucose, which positively regulate resistance to plant diseases, also exhibited elevated levels. Beneficial microorganisms, such as Bacillus were enriched in the rhizosphere soil during COS treatment. The isolated Bacillus velezensis T-2 strain exerted inhibitory activity on P. nicotianae, which was enhanced by the presence of trehalose. This multi-omics study of transcriptome, metabolome, and microbiomics revealed that COS enhances resistance to tobacco BSD by regulating sugar homeostasis and recruiting beneficial microorganisms.

Application of Konjac Glucomannan with Chitosan Coating in Yellow Alkaline Noodles

To improve the quality of the characteristics of yellow alkaline noodles and enrich their nutritional value, konjac glucomannan (KGM) with or without chitosan coating were added to noodles, and their application effects were investigated in terms of color, texture, water absorption, starch digestion, total plate count (TPC) and microstructure. Chitosan-konjac glucomannan (CK) complex was firstly prepared by embedding konjac powder with chitosan sol. After embedding, the hydrophilicity of KGM decreased significantly. Then, either CK or native KGM were mixed evenly with flour before saline water, and soda was subsequently added to produce noodles. Compared with native KGM, CK provided the noodles with a higher brightness and a lighter yellow color. In terms of texture properties, although the firmness of CK noodles was weaker than that of KGM noodles, the tensile properties were enhanced. After embedding, the water absorption of CK noodles decreased and the content of resistant starch (RS) in the noodles increased. During storage, the TPC in CK noodles was significantly lower than that in KGM noodles. At a CK content of 5%, the noodles presented a lightness of 87.41, a b value of 17.75, a shear work of 39.9 g·cm, a tensile distance of 84.28 cm, a water absorption of 69.48%, a RS content of 17.97% and a TPC of 2.74 lg CFU/g at 10 days. In general, KGM with chitosan coating could improve the physicochemical qualities of noodles and extend their shelf life to a certain extent.

Recent Updates in Pharmacological Properties of Chitooligosaccharides

Chemical structures derived from marine foods are highly diverse and pharmacologically promising. In particular, chitooligosaccharides (COS) present a safe pharmacokinetic profile and a great source of new bioactive polymers. This review describes the antioxidant, anti-inflammatory, and antidiabetic properties of COS from recent publications. Thus, COS constitute an effective agent against oxidative stress, cellular damage, and inflammatory pathogenesis. The mechanisms of action and targeted therapeutic pathways of COS are summarized and discussed. COS may act as antioxidants via their radical scavenging activity and by decreasing oxidative stress markers. The mechanism of COS antidiabetic effect is characterized by an acceleration of pancreatic islets proliferation, an increase in insulin secretion and sensitivity, a reduction of postprandial glucose, and an improvement of glucose uptake. COS upregulate the GLUT2 and inhibit digestive enzyme and glucose transporters. Furthermore, they resulted in reduction of gluconeogenesis and promotion of glucose conversion. On the other hand, the COS decrease inflammatory mediators, suppress the activation of NF-κB, increase the phosphorylation of kinase, and stimulate the proliferation of lymphocytes. Overall, this review brings evidence from experimental data about protective effect of COS.

Wheat bran with enriched gamma-aminobutyric acid attenuates glucose intolerance and hyperinsulinemia induced by a high-fat diet

In this study, the level of gamma-aminobutyric acid (GABA) in wheat bran was increased to be six times higher through the action of endogenous glutamate decarboxylase compared with untreated bran. The process of GABA formation in wheat bran also led to an increased level of phenolic compounds with enhanced antioxidant capacity 2 times higher than the untreated status. The interventional effect of a diet containing GABA-enriched bran on hyperinsulinemia induced by a high-fat diet (HFD) was investigated in a rat model. The results showed that, when compared with animals fed with HFD-containing untreated bran (NB group), the consumption of HFD-containing GABA-enriched bran (GB group) demonstrated a greater improvement of insulin resistance/sensitivity as revealed by the changes in the homeostatic model assessment for insulin resistance index (HOMA-IR) and the quantitative insulin sensitivity check index (QUICKI). The expression of hepatic genes, cytochrome P450 family 7 subfamily A member 1 (Cyp7a1) and ubiquitin C (Ubc), which are involved in the adipogenesis-associated PPAR signalling pathway, was found to be significantly down-regulated in the GB group compared with the HFD group (P = 0.0055). Meanwhile, changes in the expression of a number of genes associated with lipid metabolism and gluconeogenesis were also noted in the GB group versus the HFD group, but not in the NB group, indicating different regulatory patterns between the two brans in a high-fat diet. More importantly, the analysis of key genes related to glucose metabolism further revealed that the expression of insulin-induced gene 1/2 (Insig-1/2) was increased following GB intervention with a corresponding reduction in phosphoenolpyruvate carboxykinase 1 (Pepck) and glucose-6-phosphatase, catalytic subunit (G6pc) expression, suggesting that glucose homeostasis is greatly improved through the intervention of GABA-enriched bran in the context of a high-fat diet.

Characterization of fecal fat composition and gut derived fecal microbiota in high-fat diet fed rats following intervention with chito-oligosaccharide and resistant starch complexes

The current study analyzed the different effects of intervention in high-fat diet fed rats using chito-oligosaccharides (CO group), resistant starch (RS group) and their complexes (CO–RS group), respectively.