Comparison of distribution and physicochemical properties of β-glucan extracted from different fractions of highland barley grains

Valorization of barley (Hordeum vulgare L.) brans from the sustainable perspective: A comprehensive review of bioactive compounds and health benefits with emphasis on their potential applications

Barley is an important source of sustainable diets for humans, while its brans is commonly disposed as wastes. The recycling of barley brans has become a key for facilitating the valorization of barley as a whole to achieve its sustainable development. This review summarized the value of barley brans as an excellent source of multiple functional components (phenolic compounds, β-glucan, and arabinoxylan), which conferred extensive health benefits to barley brans mainly including antioxidant, anti-obesity and lipid-lowering, anti-diabetic, and hepatoprotective properties. The utilization of barley brans reflected a great potential for sustainable development. Exploiting of food products and edible films containing barley brans or their bioactive compounds and non-food applications (preparation of bioactive substances, laccase enzymes, and biosorbents) have been attempted for supporting the zero-waste concept and circular economy. Considering their diverse applications, effective extraction techniques of bioactive compounds from barley brans and their safety are the priority of future research.

Assessing the influences of β-glucan on highland barley starch: Insights into gelatinization and molecular interactions

Developing highland barley products is complex, possibly due to the presence of β-glucan in highland barley. This study aims to investigate the impact of β-glucan on the physicochemical properties, microstructure, and molecular interactions of highland barley starch (HBS) during gelatinization and aging. Increasing the β-glucan content significantly reduced peak viscosity, setback viscosity, and breakdown viscosity, indicating altered gelatinization behavior. The β-glucan content increase caused a significant drop in peak viscosity. With 20% β-glucan addition, it reduced by 883 mPa·s, nearly 38%. Rheological analysis showed a transition from a solid-like to a liquid-like texture or quality, ultimately leading to a shear-thinning behavior. Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) confirmed the interaction between HBS and β-glucan via intermolecular hydrogen bonding, promoting the formation of double helical structures in starch. These findings provide a deeper understanding of the role of β-glucan in the processing of highland barley, highlighting its influence on the starch's properties.

β-Glucan-based superabsorbent hydrogel acts as a gastrointestinal exoskeleton enhancing satiety and interfering fat hydrolysis

Fat and its hydrolysis products, fatty acids, are indispensable nutritional components; however, prolonged excessive fat consumption, particularly in western diets, contributes to the onset of obesity and multiple metabolic disorders. In this study, we propose a daily-ingestible hydrogel (denoted as βC-MA hydrogel) composed of natural β-glucan and sodium carboxymethylcellulose crosslinked by malic acid at 120 °C. This hydrogel exhibits rapid swelling performance, up to 24-fold within 1 min and 176-fold after 1 h in deionized water. It also lengthens gastric retention and increases endogenous satiety signal levels, potentially controlling appetite and reducing food intake. Furthermore, βC-MA hydrogels that enter the small intestine can effectively inhibit fat hydrolysis and decrease triglyceride synthesis and transport. Specifically, the hydrogels inhibit the release of free fatty acids (FFAs) by approximately 50 % during digestion, influence the translocation of triglycerides and FFAs across the intestinal epithelium, and reduce the serum triglyceride levels by 22.2 %. These findings suggest that βC-MA hydrogels could serve as a noninvasive gastrointestinal device for weight control, with the advantage of reducing food intake and restoring lipid metabolism homeostasis.

Structural characteristics of β-glucans from various sources and their influences on the short- and long-term starch retrogradation in wheat flour

Beta-glucans possess the ability of retarding starch retrogradation. However, β-glucans from different sources might show various influences on retrogradation process and the structure-function relationships of β-glucans related to the feature still remains unclear. In the study, the β-glucans from oat (OG), highland barley (HBG), and yeast (YG) were selected. Each β-glucans formed aggregate as observed by atomic force microscopy. OG and HBG with a lower Mw aggregated more obviously and exhibited higher intrinsic and apparent viscosity. The two β-glucans showed more restraining effect on the short-term starch retrogradation in the sol-like test system (RVA) and the long-term starch retrogradation in the gel-like test system (DSC). However, YG with a higher Mw exerted a greater retarding effect on the short-term starch retrogradation in gel-like test systems (Mixolab and rheology). LF-NMR indicated that OG and HBG increased the population of less-bound water by wrapping around the starch. In summary, the structural characteristics of β-glucan (Mw and aggregation state) and experiment condition (solid content) jointly influenced starch retrogradation, because a lower Mw and higher aggregation capacity β-glucan interacted more readily with starch and inhibited more starch re-association due to the higher diffusion rate in the sol-like system.

Extraction, purification, structural characteristics, bioactivity and potential applications of polysaccharides from Avena sativa L.: A review

Avena sativa L. (A. sativa L.), commonly known as oat, is a significant cereal grain crop with excellent edible and medicinal value. Oat polysaccharides (OPs), the major bioactive components of A. sativa L., have received considerable attention due to their beneficial bioactivities. However, the isolation and purification methods of OPs lack innovation, and the structure-activity relationship remains unexplored. This review emphatically summarized recent progress in the extraction and purification methods, structural characteristics, biological activities, structure-to-function associations and the potential application status of OPs. Different materials and isolation methods can result in the differences in the structure and bioactivity of OPs. OPs are mainly composed of various monosaccharide constituents, including glucose, arabinose and mannose, along with galactose, xylose and rhamnose in different molar ratios and types of glycosidic bonds. OPs exhibited a broad molecular weight distribution, ranging from 1.34 × 105 Da to 4.1 × 106 Da. Moreover, structure-activity relationships demonstrated that the monosaccharide composition, molecular weight, linkage types, and chemical modifications are closely related to their multiple bioactivities, including immunomodulatory activity, antioxidant effect, anti-inflammatory activity, antitumor effects etc. This work can provide comprehensive knowledge, update information and promising directions for future exploitation and application of OPs as therapeutic agents and multifunctional food additives.

Influence of physicochemical changes and aggregation behavior induced by ultrasound irradiation on the antioxidant effect of highland barley β-glucan

The effect of ultrasonic treatment on the structure, morphology and antioxidant activity of highland barley β-glucan (HBG) was investigated. Ultrasonic treatment for 30 min was demonstrated to improve the aqueous solubility of HBG, leading to a decrease in turbidity. Meanwhile, moderate ultrasound was found to obviously reduce the particle size distribution of HBG, and transform the entangled HBG molecules into flexible and extended chains, which reaggregated to form larger aggregates under long-time ultrasonication. The in vitro antioxidant capacity of HBG treated by ultrasonic first increased and then decreased compared to native HBG. Congo red complexation analysis indicated the existence of helix structure in HBG, which was untwisted after ultrasonic treatment. Furthermore, ultrasound treatment influenced the glucopyranose on HBG, which weakened the intramolecular hydrogen bond of HBG. The microscopic morphology showed that the spherical aggregates in native HBG solution were disaggregated and the untangled HBG chains reaggregated with excessive ultrasonication.