Oat fibre: overview on their main biological properties

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.

Common Wheat Pasta Enriched with Ultrafine Ground Oat Husk: Physicochemical and Sensory Properties

Oat husk (hull) is a byproduct of oat processing that is rich in insoluble fiber. The aim of the study was to evaluate the effect of partially replacing wheat flour with oat husk (at levels of 0, 5, 10, 15, and 20 g/100 g) on the physicochemical properties and sensory acceptance of pasta. Additionally, UPLC-MS/MS analysis was performed to identify phenolic acids and flavonoid compounds, and the cooking properties of the pasta were evaluated. The test results indicate that oat husk significantly (p < 0.05) increased the ash and fiber contents in the pasta, while decreasing the protein and fat contents. Moreover, the redness and yellowness of both raw and cooked pasta increased, while lightness decreased as a result of pasta enrichment with oat husk. Oat husk also led to a decrease in the stretching force of cooked samples, although cooking loss increased significantly but did not exceed 8%. The contents of phenolics and antioxidant activity significantly increased with the incorporation of hull in pasta recipes. UPLC-MS/MS analysis showed that the enriched pasta was especially abundant in ferulic acid. Products with up to 10 g of husk/100 g of wheat flour showed good consumer acceptance. However, higher levels of this additive led to notably lower assessments, particularly in terms of pasta texture.

Efficient production and skincare activity evaluation of schizophyllan, a β-glucan derived from Schizophyllum commune NTU-1

Schizophyllan (SPG), a β-glucan produced by the fungus Schizophyllum commune, possesses a β-(1 → 3)-linked backbone with single β-(1 → 6)-linked glucose side chains at approximately every third residue. In this study, we screened SPG-producing strains of S. commune from different provinces in China. A candidate strain (NTU-1) with a high SPG yield was chosen, and the fermentation conditions were optimized. The optimal carbon and nitrogen sources were sucrose (40 g/L) and yeast extract (20 g/L), respectively. The optimal conditions for pH and temperature were 5.0 and 28 °C, respectively. Inclusion of 0.2 mg/L of 2,4-Dichlorophenoxyacetic acid in the medium further increased the SPG concentration. In a 5-L bioreactor, the fermentation cycle was reduced from the initial seven days to five days, and the concentration of SPG obtained was 21.3 g/L, which is the highest reported to date. In addition, we evaluated the bioactivity of the SPG prepared using strain NTU-1. The results showed that SPG had certain characteristics of anti-oxidation, anti-photoaging, and inhibition of melanin production, making it a promising reagent for skin care.

Oil-in Water Vegetable Emulsions with Oat Bran as Meat Raw Material Replacers: Compositional, Technological and Structural Approach

The unique composition and technological properties of some oat bran components (mainly protein and soluble fiber) and olive oil make them a good choice to form oil-in-water vegetable emulsions. The different concentrations of oat bran were studied to form olive oil-in water (O/W) emulsions to apply as a replacement for fat and meat. As a result, four O/W emulsions (OBE) were formulated with 10% (OBE10), 15% (OBE15), 20% (OEB20), and 30% (OBE30) oat bran concentrations and 40% olive oil, with the corresponding amount of water added for each O/W emulsion. Composition, technological properties (thermal stability, pH, texture), and lipid structural characteristics were evaluated. The results showed that low oat bran content (OEB10)-with a lower concentration of oat protein and β-glucans-resulted in an O/W emulsion with an aggregated droplet structure and lower thermal stability and hardness. These connections between composition, technology, and structural properties of olive O/W emulsions elaborated with oat bran could help in making the optimal choice for their potential application in the production of foods such as healthier meat products.

Dominant hydrophobic interactions with β-glucan in nanoarchitectonics with mixed Langmuir monolayers of cholesterol/dipalmitoyl phosphatidyl choline

The polysaccharide β-glucan, found in the cell wall of cereals such as wheat, oats, and barley, is believed to lower the concentration of bad cholesterol in humans, but the molecular-level mechanisms responsible for such an action are unknown. In this study, we use Langmuir monolayers of cholesterol and dipalmitoyl phosphatidyl choline (DPPC) as cell membrane models that are made to interact with β-glucan. Neat cholesterol and mixed cholesterol/DPPC monolayers were expanded upon incorporating β-glucan from the aqueous subphase. This incorporation was found to induce ordering in mixed monolayers and dehydration of the carbonyl group at higher cholesterol concentrations. These effects are attributed to hydrophobic interactions as identified with polarization-modulated infrared reflection-absorption spectroscopy. They correlate well with the hypothesis that cholesterol levels can be lowered by the formation of soluble fibers with β-glucan through hydrophobic interactions, blocking cholesterol absorption by the organism.

Quantification of Oil Fractions of Deep-Fried Wheat Dough and Batter Enriched with Oat and Wheat Bran

This study investigated oil distribution in two types of deep-fried dough products with two moisture levels (65 and 100 wt. %), two bran types (oat and wheat bran), and five bran concentrations (5–20%). The total oil content of fried products was categorised as surface oil (SO), penetrated surface oil (PSO), and structural oil (STO) using a spectrophotometric method. Moisture loss reduced ( $p<0.05$ ) from 23.35% in the control to 15.19% fried batter (FB) and to 20% oat bran (OB), while a reverse trend was observed in the fried dough. Reduction of total oil from 0.43 g/g in the control to 0.38 g/g at 20% OB and 8% wheat bran (WB) was observed. At 15% OB and 20% WB, total fat reduced from 0.41 g/g in the control to 0.26 g/g of fried dough (FD). The trend STO < SO < PSO was observed in FD, while FB followed a SO < STO < PSO trend. This investigation indicated that oil uptake reduction in fried dough products is achievable through ingredient modifications. The method of oil distribution measurement used herein can be applied to other thick deep-fried food systems in the assessment of product quality.

Dietary pectin and mango pulp effects on small intestinal enzyme activity levels and macronutrient digestion in grower pigs

The effects of refined pectin and mango pulp on macronutrient digestion and small intestinal enzyme activity were studied in grower pigs. Diets based on wheat starch with and without apple pectin or dried mango fruit pulp were fed to 30 grower pigs for 21 days. Pigs were euthanized two hours postprandially, and their gastrointestinal contents recovered. Starch and protein digestion as well as α-amylase activity were all increased in pigs fed pectin. In contrast, fat digestion, lipase and protease (trypsin) activities were all significantly reduced in these pigs. Pigs fed the mango fruit pulp diet had intermediate effects compared with pigs fed refined pectin and control diets. The data suggests that pectin has a significant effect on digestive enzyme activity and subsequent influence on macronutrient digestion. The fact that pectin caused either an increase (α-amylase) or decrease (lipase, protease) in enzyme activity in digesta, which either did (starch, lipid) or did not (protein) associate with residual nutrient differences illustrates the complexity of small intestinal responses to added fibre in diets.

Solvent Retention Capacities of Oat Flour

This study measured the solvent retention capacities (SRCs) of flours from eight oat varieties and one wheat variety against different solvents to explore the swelling volume of oat flour with different solvents, and thus provide a theoretical basis for quick β-glucan analysis. The SRC profile consists of water SRC (WSRC), 50% sucrose SRC (SSRC), 5% lactic acid SRC (LASRC), 5% Na₂CO₃ SRC (SCASRC), NaCl SRC (SCSRC), CaCl₂ SRC (CCSRC), FeCl₃ SRC (FCSRC), sodium cholate SRC (SCHSRC), NaOH (pH 10) SRC (SHSRC), Na₂CO₃ (pH 10) SRC (SCABSRC) and SDS (pH 10) SRC (SDSSRC) values, and a Chopin SRC kit was used to measure the SRC value. SRCs of the oat flours increased when the solvents turned from neutral (water and NaCl) to acidic (5% lactic acid) or alkaline (5% Na₂CO₃, CaCl₂, FeCl₃, NaOH and pH 10 Na₂CO₃), and rose as the metal ion valencies of the metal salts (NaCl, CaCl₂ and FeCl₃) increased. The β-glucan contents were significantly positively correlated with the SCSRC (0.83**), CCSRC (0.82**), SCHSRC (0.80**) and FCSRC (0.78*). SRC measurements of β-glucan in oat flours revealed that the CCSRC values were related with β-glucan (0.64*) but not related with protein and starch. CaCl₂ could therefore potentially be exploited as a reagent for β-glucan assay.