Structural characterization and evaluation of antioxidant, anticancer and hypoglycemic activity of radiation degraded oat (Avena sativa) β- glucan

Structural relationship of regioselectively-sulfonated botryosphaeran derivatives on activity against herpes simplex virus type 1

The bioactivities of sulfonated polysaccharides are frequently related to their substitution pattern. In this study, the regioselective sulfonation of an exocellular fungal (1→3)(1→6)-β-D-glucan (botryosphaeran) was performed by two different methods: mild sulfonation (MS) and via pivaloyl ester (PS), in order to study the influence of the sulfonation pattern on the antiviral activity of the respective derivatives. Two sulfonated derivatives with substitution degrees of 0.82 (MS) and 0.49 (PS) were obtained, with substitution patterns at positions C-6, and C-2/C-4 of the glucose units, respectively. All derivatives were chemically characterized and evaluated for antiviral activity against Herpes simplex virus type 1 (HSV-1) KOS strain, and dengue type 2 (DENV-2). The sample sulfonated at positions C-6 (MS) showed a remarkable antiviral effect on HSV-1 (IC50 of 5.38 μg mL1), while PS remained inactive. The investigation of the mode of action of sample MS pointed to the inhibition of HSV-1 adsorption to the host cells. Both samples were inactive towards the dengue virus strain. This study demonstrated that the presence of sulfate groups at the C-6 positions of botryosphaeran is the preferred substitution pattern that enables the antiviral activity towards HSV-1.

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.

Potential promising anticancer applications of β-glucans: a review

β-Glucans are valuable functional polysaccharides distributed in nature, especially in the cell walls of fungi, yeasts, bacteria, and cereals. The unique features of β-glucans, such as water solubility, viscosity, molecular weight, and so on, have rendered them to be broadly applied in various food systems as well as in medicine to improve human health. Moreover, inhibition of cancer development could be achieved by an increase in immune system activity via β-glucans. β-glucans, which are part of a class of naturally occurring substances known as biological response modifiers (BRMs), have also shown evidence of being anti-tumorogenic, anti-cytotoxic, and anti-mutagenic. These properties make them attractive candidates for use as pharmaceutical health promoters. Along these lines, they could activate particular proteins or receptors, like lactosylceramide (LacCer), Dickin-1, complement receptor 3 (CR3), scavenge receptors (SR), and the toll-like receptor (TLR). This would cause the release of cytokines, which would then activate other antitumor immune cells, like macrophages stimulating neutrophils and monocytes. These cells are biased toward pro-inflammatory cytokine synthesis and phagocytosis enhancing the elicited immunological responses. So, to consider the importance of β-glucans, the present review introduces the structure characteristics, biological activity, and antitumor functions of fungal β-glucans, as well as their application.

Effects of grafting methods and raw materials on the physicochemical properties and biological activities of phenolic acids grafted oat β-glucan

Phenolic acids are commonly used as food biological preservatives. Grafting phenolic acids onto polysaccharides could effectively enhance their biological activities and environmental stability to varying degrees. However, grafting methods and raw materials could affect the physical properties and biological activities of the phenolic acid-grafted polysaccharides. In this study, caffeic acid (CA) and gallic acid (GA) were grafted onto oat β-glucan (OG) and hydrolyzed oat β-glucan (OGH) through N,N'-carbonyldiimidazole-mediated (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride coupling N-hydroxysuccinimide (EDC/NHS) methods. Graft modification decreased the crystallinity and thermal stability of the conjugates, but retained good bioactivities for the conjugates. The antioxidant and bacteriostatic activities of the conjugates prepared by the EDC method were better than those of the CDI method, and the OGH-conjugates showed better biological activities than OG-conjugates. EDC-GAOGH showed best DPPH (89.78%) and ABTS (92.32%) scavenging activities. The inhibitory effect of EDC-GAOGH on Escherichia coli was significantly better than that of EDC-CAOGH, but for Staphylococcus aureus, the results are opposite, which indicating that different phenolic acid grafting products have different inhibitory effects on pathogenic microbes. In general, grafting phenolic acids onto OGH using EDC method is an effective strategy for preparing food biological preservative.

The Impact of Food Processing on the Structure and Hypoglycemic Effect of Oat β-glucan

The impact of food processing including baking, steaming and bread making, on the structure and hypoglycemic effect of oat β-glucan was studied. The structural analysis revealed the β-D-glucopyranosyl units of β-glucan was unchanged in aforementioned processing. The baking processing endowed β-glucan with increased molecular weight (Mw) and viscosity, which enhanced the capacity of β-glucan to delay starch digestion in vitro, such as the rapidly-digestible starch content decreased, the slowly-digestible and resistant starch content increased, and the glycemic index (GI) value decreased. Meanwhile, the inhibitory activity of β-glucan against α-glucosidase and α-amylase was enhanced by baking processing. By contrast, during steaming and bread making processing, β-glucan showed decreased Mw and viscosity, which accelerated starch digestion in vitro and reduced the inhibitory activity of β-glucan against α-glucosidase and α-amylase. Apart from that, baking processing promoted the physiological and antioxidant properties of β-glucan, but the properties decreased during steaming and bread making processing. The results suggest that oat raw materials can be treated with dry heat and high temperature, avoiding moist heat and fermentation treatments to maximize the hypoglycemic effect of β-glucan.

Study on the preparation and biological activities of low molecular weight squid ink polysaccharide from Sepiella maindroni

Sepiella maindroni ink polysaccharide (SIP) from the ink of cuttlefish Sepiella maindroni and its sulfated derivative (SIP-SII) have been demonstrated to possess diverse biological activities. But little is known about low molecular weight squid ink polysaccharides (LMWSIPs). In this study, LMWSIPs were prepared by acidolysis, and the fragments with molecular weight (M_w) distribution in the ranges of 7 kDa to 9 kDa, 5 kDa to 7 kDa and 3 kDa to 5 kDa were grouped and named as LMWSIP-1, LMWSIP-2 and LMWSIP-3, respectively. The structural features of LMWSIPs were elucidated, and their anti-tumor, antioxidant and immunomodulatory activities were also studied. The results showed that with the exception of LMWSIP-3, the main structures of LMWSIP-1 and LMWSIP-2 did not change compared with SIP. Though there were no significant differences in the antioxidant capacity between LMWSIPs and SIP, the anti-tumor and immunomodulatory activities of SIP were enhanced to a certain extent after degradation. It is particularly noteworthy that the activities of LMWSIP-2 in anti-proliferation, promoting apoptosis and inhibiting migration of tumor cells as well as promoting the proliferation of spleen lymphocytes were significantly higher than those of SIP and the other degradation products, which is promising in the anti-tumor pharmaceutical field.

Perspectives in the Application of High, Medium, and Low Molecular Weight Oat β-d-Glucans in Dietary Nutrition and Food Technology-A Short Overview

For centuries human civilization has cultivated oats, and now they are consumed in various forms of food, from instant breakfasts to beverages. They are a nutrient-rich food containing linear mixed-linkage (1 → 3) (1 → 4)-β-d-glucans, which are relatively well soluble in water and responsible for various biological effects: the regulation of the blood cholesterol level, as well as being anti-inflammatory, prebiotic, antioxidant, and tumor-preventing. Numerous studies, especially in the last two decades, highlight the differences in the biological properties of the oat β-d-glucan fractions of low, medium, and high molecular weight. These fractions differ in their features due to variations in bioavailability related to the rheological properties of these polysaccharides, and their association with food matrices, purity, and mode of preparation or modification. There is strong evidence that, under different conditions, the molecular weight may determine the potency of oat-extracted β-d-glucans. In this review, we intend to give a concise overview of the properties and studies of the biological activities of oat β-d-glucan preparations depending on their molecular weight and how they represent a prospective ingredient of functional food with the potential to prevent or modulate various pathological conditions.

Simultaneously enhanced stability and biological activities of chlorogenic acid by covalent grafting with soluble oat β-glucan

Chlorogenic acid (CA) has a wide range of biological activities but the chemical structure is extremely unstable. In this study, CA was grafted onto a soluble oat β-glucan (OβGH) to improve the stability. Although the crystallinity and thermal stability of CA-OβGH conjugates reduced, the storage stability of CA significantly improved. The DPPH and ABTS scavenging ability of CA-OβGH IV (graft ratio 285.3 mg CA/g) were higher than 90 %, which is closed to activities of equivalent concentration of Vc (93.42 %) and CA (90.81 %). The antibacterial abilities of CA-OβGH conjugates are improved compared to the equivalent content of CA and potassium sorbate. Particularly, the inhibition rate of CA-OβGH for gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) are significantly higher than that of gram-negative bacteria (Escherichia coli). The results demonstrated that covalent grafted CA with soluble polysaccharide is an effective strategy to enhance its stability and biological activities.

The Potential Functions and Mechanisms of Oat on Cancer Prevention: A Review

Oat is classified as a whole grain and contains high contents of protein, lipids, carbohydrates, vitamins, minerals, and phytochemicals (such as polyphenols, flavonoids, and saponins). In recent years, studies have focused on the effects of oat consumption on reducing the risk of a variety of diseases. Reports have indicated that an oat diet exerts certain biological functions, such as preventing cardiovascular diseases, reducing blood glucose, and promoting intestinal health, along with antiallergy, antioxidation, and cancer preventive effects. At present, cancer is the second leading cause of death worldwide. The natural products of oat are an important breakthrough for developing new strategies of cancer prevention, and their ability to interact with multiple cellular targets helps to combat the complexity of cancer pathogenesis. In addition, the comprehensive study of the cancer prevention activity and potential mechanism of oat nutrients and phytochemicals has become a research hotspot. In this Review, we focused on the potential functions of peptides, dietary fiber, and phytochemicals in oats on cancer prevention and further revealed novel mechanisms and prospects for clinical application. These findings might provide a novel approach to deeply understand the functions and mechanisms for cancer prevention of oat consumption.

Integrated transcriptomics and metabolomics unravel the metabolic pathway variations for barley β-glucan before and after fermentation with L. plantarum DY-1

The results of our previous study showed that the structure and function of β-glucan in barley were changed after fermentation by L. plantarum DY-1. In this study, the antioxidant activities of RBG (regular barley β-glucan, unfermented) and FBG (barley β-glucan, fermented with L. plantarum DY-1) were evaluated by adopting an in vivo animal model, Caenorhabditis elegans (C. elegans). We also carried out an integrated transcriptomic and metabolomic profiling for RBG and FBG to delineate their signature pathways. RBG treatment has better effects on SOD enzyme activity and ROS levels than FBG, while FBG treatment has better effects on the CAT enzyme activity and MDA content than RBG in C. elegans. Transcription group analysis showed that FBG mainly decreases the expression of the Cyp-D gene to inhibit the calcium signaling pathway, promotes the Wnt signaling pathway by up-regulating the GSK-3β gene and improving the oxidative damage of C. elegans; RBG mainly inhibits calcium signal pathways by reducing the expression of ANT-solute carrier family 25 genes, promoting life adjustment pathways by reducing the expression of the HSP-12.6 gene to improve the oxidative stress of C. elegans. Joint analysis showed that the difference between FBG and RBG in the regulation of oxidative stress is mainly reflected in the metabolism pathway of arachidonic acid. Under the regulation of FBG, the expression of the C03H5.4 gene was decreased, the expression of leukotriene A4, prostaglandin G2, arachidonic acid and phosphatidylcholine was decreased, and the expression of 14,15-DiHETrE was increased. Under the regulation of RBG, the expression of gene C03H5.4 was up-regulated, the expression of metabolites such as leukotriene B4 was up-regulated, and the expression of arachidonic acid and phosphatidylcholine was down-regulated.

Use of the β-Glucan-Producing Lactic Acid Bacteria Strains Levilactobacillus brevis and Pediococcus claussenii for Sourdough Fermentation-Chemical Characterization and Chemopreventive Potential of In Situ-Enriched Wheat and Rye Sourdoughs and Breads

The aim of the present study was to examine β-glucan production and the potential prebiotic and chemopreventive effects of wheat and rye sourdoughs and breads generated with wild-type and non-β-glucan-forming isogenic mutant strains of Levilactobacillus brevis and Pediococcus claussenii. Sourdough and bread samples were subjected to in vitro digestion and fermentation. Fermentation supernatants (FS) and pellets (FP) were analyzed (pH values, short-chain fatty acids (SCFA), ammonia, bacterial taxa) and the effects of FS on LT97 colon adenoma cell growth, viability, caspase-2 and -3 activity, genotoxic and antigenotoxic effects and on gene and protein expression of p21, cyclin D2, catalase and superoxide dismutase 2 (SOD2) were examined. Concentrations of SCFA were increased and concentrations of ammonia were partly reduced in the FS. The relative abundance of Bifidobacteriaceae was increased in all FPs. Treatment with FS reduced the growth and viability of LT97 cells and significantly increased caspase-2 and -3 activities without exhibiting genotoxic or antigenotoxic effects. The p21 mRNA and protein levels were increased while that of cyclin D2 was reduced. Catalase and SOD2 mRNA and protein expression were marginally induced. The presented results indicate a comparable chemopreventive potential of wheat and rye sourdoughs and breads without an additional effect of the formed β-glucan.

Effects of L.plantarum dy-1 fermentation time on the characteristic structure and antioxidant activity of barley β-glucan in vitro

This article explored the effect of Lactobacillus plantarum dy-1 (L. plantarum dy-1) fermentation on the basic physicochemical properties and associated in vitro antioxidant activity of barley β-glucan, including its molecular weight, monosaccharide composition, characteristic structure and rheology. Its DPPH, ABTS, hydroxyl radical scavenging capacity, and ferric reducing antioxidant potential (FRAP) were measured at different fermentation times. The results showed that the molecular weight of barley β-glucan was decreased from 1.052 × 10⁵ Da to 4.965 × 10⁴ Da within 0–24 h by L. plantarum dy-1 fermentation, but there was no effect on its characteristic structure. The water- and oil-holding properties of barley β-glucan were significantly enhanced with increased fermentation time, and the fluid viscous behavior of barley β-glucan was enhanced at 6% concentration, while elastic characteristics were weakened. The fermentation had no significant effect on the scavenging effect of DPPH and ABTS radicals of barley β-glucan, but the hydroxyl radical scavenging activity and total antioxidant capacity of FRAP were enhanced with increased fermentation time. Fermentation time may change the physicochemical properties and enhance antioxidant activity of barley β-glucan by reducing its molecular weight.

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Increase the study on the effect of lactic acid bacteria fermentation on the antioxidant activity of barley β-glucan.

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The water-retaining and oil-controlling properties of barley β-glucan increased significantly.

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Fermentation time may enhance physicochemical properties and antioxidant activity of barley β-glucan.

Barley β-glucan resist oxidative stress of Caenorhabditis elegans via daf-2/daf-16 pathway

β-glucan is an important functional active component with relatively high content in barley. It is reported to possess various biological activities, including anti-oxidative stress, but its mechanism of action remains obscure. In the current study, C. elegans was used as an in vivo animal model to explore its anti-oxidative stress mechanism. We found that both RBG (raw barley β-glucan) and FBG (fermented barley β-glucan) could significantly reduce the ROS level in C. elegans under oxidative emergency conditions. In addition, both FBG and RBG had positive effects on SOD and CAT enzyme activity, and FBG treatment obviously reduced the MDA content in nematodes under oxidative stress. Moreover, FBG and RBG pretreatment could extend the median lifespan of C. elegans under oxidative stress. The CB1370 and CF1038 mutants further confirmed that daf-2 and daf-16 were necessary for FBG or RBG to participate in anti-oxidative stress, and the RT-PCR results also evidenced that β-glucans resist oxidative stress in C. elegans partially through the daf-2/daf-16 pathway. In summary, barley β-glucan has high potential to defense oxidative stress as a natural polysaccharide.

Fermentation profile, cholesterol-reducing properties and chemopreventive potential of β-glucans from Levilactobacillus brevis and Pediococcus claussenii - a comparative study with β-glucans from different sources

The aim of the present study was to investigate whether β-glucans obtained from the lactic acid bacteria (LAB) Levilactobacillus (L.) brevis and Pediococcus (P.) claussenii exhibit similar physiological effects such as cholesterol-binding capacity (CBC) as the structurally different β-glucans from oat, barley, and yeast as well as curdlan. After in vitro fermentation, fermentation supernatants (FSs) and/or -pellets (FPs) were analyzed regarding the concentrations of short-chain fatty acids (SCFAs), ammonia, bile acids, the relative abundance of bacterial taxa and chemopreventive effects (growth inhibition, apoptosis, genotoxicity) in LT97 colon adenoma cells. Compared to other glucans, the highest CBC was determined for oat β-glucan (65.9 ± 8.8 mg g^-1, p < 0.05). Concentrations of SCFA were increased in FSs of all β-glucans (up to 2.7-fold). The lowest concentrations of ammonia (down to 0.8 ± 0.3 mmol L^-1) and bile acids (2.5-5.2 μg mL^-1) were detected in FSs of the β-glucans from oat, barley, yeast, and curdlan. The various β-glucans differentially modulated the relative abundance of bacteria families and reduced the Firmicutes/Bacteroidetes ratio. Treatment of LT97 cells with the FSs led to a significant dose-dependent growth reduction and increase in caspase-3 activity without exhibiting genotoxic effects. Though the different β-glucans show different fermentation profiles as well as cholesterol- and bile acid-reducing properties, they exhibit comparable chemopreventive effects.

Development of a novel beta-glucan supplemented hydrogel spray formulation and wound healing efficacy in a db/db diabetic mouse model

To relief the severe economic and social burdens and patient suffering caused by the increasing incidence of chronic wounds, more effective treatments are urgently needed. In this study, we focused on developing a novel sprayable wound dressing with the active ingredient β-1,3/1,6-glucan (βG). Since βG is already available as the active ingredient in a commercial wound healing product provided as a hydrogel in a tube (βG-Gel), the sprayable format should bring clinical benefit by being easily sprayed onto wounds; whilst retaining βG-Gel's physical stability, biological safety and wound healing efficacy. Potentially sprayable βG hydrogels were therefore formulated, based on an experimental design setup. One spray formulation, named βG-Spray, was selected for further investigation, as it showed favorable rheological and spraying properties. The βG-Spray was furthermore found to be stable at room temperature for more than a year, retaining its rheological properties and sprayability. The cytotoxicity of βG-Spray in keratinocytes in vitro, was shown to be promising even at the highest tested concentration of 100 μg/ml. The βG-Spray also displayed favorable fluid affinity characteristics, with a capacity to both donate and absorb close to 10% fluid relative to its own weight. Finally, the βG-Spray was proven comparably effective to the commercial product, βG-Gel, and superior to both the water and the carrier controls (NoβG-Spray), in terms of its ability to promote wound healing in healing-impaired animals. Contraction was found to be the main wound closure mechanism responsible for the improvement seen in the βG-treatment groups (βG-Spray and βG-Gel). In conclusion, the novel sprayable βG formulation, confirmed its potential to expand the clinical use of βG as wound dressing.

Combination of natural antivirals and potent immune invigorators: A natural remedy to combat COVID-19

The flare‐up in severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) that emerged in December 2019 in Wuhan, China, and spread expeditiously worldwide has become a health challenge globally. The rapid transmission, absence of anti‐SARS‐CoV‐2 drugs, and inexistence of vaccine are further exacerbating the situation. Several drugs, including chloroquine, remdesivir, and favipiravir, are presently undergoing clinical investigation to further scrutinize their effectiveness and validity in the management of COVID‐19. Natural products (NPs) in general, and plants constituents specifically, are unique sources for various effective and novel drugs. Immunostimulants, including vitamins, iron, zinc, chrysin, caffeic acid, and gallic acid, act as potent weapons against COVID‐19 by reinvigorating the defensive mechanisms of the immune system. Immunity boosters prevent COVID‐19 by stimulating the proliferation of T‐cells, B‐cells, and neutrophils, neutralizing the free radicals, inhibiting the immunosuppressive agents, and promoting cytokine production. Presently, antiviral therapy includes several lead compounds, such as baicalin, glycyrrhizin, theaflavin, and herbacetin, all of which seem to act against SARS‐CoV‐2 via particular targets, such as blocking virus entry, attachment to host cell receptor, inhibiting viral replication, and assembly and release.

Innovative biosynthesis of silver nanoparticles using yeast glucan nanopolymer and their potentiality as antibacterial composite

Nanometals (NM) frequently possess potent antimicrobial potentials to combat various pathogens, but their elevated biotoxicity limits their direct applications. The biosynthesis of NM and their capping/conjugation with natural biopolymers can effectually enhance NM stability and diminish such toxicity. Yeast β-glucan (βG), from Saccharomyces cerevisiae, was extracted and transformed to nanoparticles (NPs) using alkali/acid facile protocol. The βG NPs were innovatively employed for direct biosynthesis of silver nanoparticles (Ag NPs) without extra chemical processes. The physicochemical assessments (Fourier-transform infrared, X-ray diffraction, and transmission electron microscopy) validated NPs formation, interaction, and interior capping of Ag NPs in βG NPs. The synthesized βG NPs, Ag NPs, and βG-Ag NPs composite were negatively charged and had minute particle sizes with mean diameters of 58.65, 6.72, and 63.88 nm, respectively. The NPs (plain Ag NPs and composited βG-Ag NPs) exhibited potent comparable bactericidal actions, opposing Gram⁺ (Staphylococcus aureus) and Gram^- (Escherichia coli, Salmonella Typhimurium, and Pseudomonas aeruginosa). Scanning micrographs, of treated S. aureus and S. Typhimurium with βG-Ag NPs, elucidated the powerful bactericidal actions of nanocomposite for destructing pathogens' cells. The inventive Ag NPs biosynthesis with βG NPs and the combined βG-Ag NPs nanocomposites could be impressively recommended as powerful antibacterial candidates with minor potential toxicity.

Preparation and Characterization of Fish Skin Collagen Material Modified with β-Glucan as Potential Wound Dressing

Collagen possesses unique properties, e.g., biocompatibility, biodegradability, and non-toxicity. However, collagen material degrades too quickly and has low mechanical properties. One of the methods of polymers' modification is mixing them to obtain blends. In this study, the influence of β-glucan for collagen material was analyzed. The interaction between the functional groups of the polymer was analyzed by ATR-FTIR (attenuated total reflection-fourier transform infrared) spectroscopy. The influence of β-glucan on mechanical properties was evaluated. The surface properties of materials were assessed using contact angle measurements and the topography of materials was evaluated by AFM (atomic force microscope). The structure of materials was analyzed according to SEM (scanning electron microscopy) pictures. Moreover, the DPPH-free radicals' scavenging ability and biocompatibility against erythrocytes and HaCaT cells were evaluated. Collagen and β-glucan were bound together by a hydrogen bond. β-glucan addition increased the roughness of the surface of the film and resulted in a more rigid character of the materials. A small addition of β-glucan to collagen provided a more hydrophilic character. All the materials could swell in in vitro conditions and showed antioxidant activity. Materials do not cause erythrocyte hemolysis. Finely, our cytotoxicity studies indicated that β-glucan can be safely added at small (10% or less) quantity to collagen matrix, they sufficiently support cell growth, and the degradation products of such matrices may actually provide some beneficial effects to the surrounding cells/tissues.

Thermal Processing has no Impact on Chemopreventive Effects of Oat and Barley Kernels in LT97 Colon Adenoma Cells

The unique dietary fiber composition with high contents of β-glucan contributes to the health-promoting properties of oat and barley and may mediate a reduction of colon cancer risk. In the present study, chemopreventive effects of oat and barley (beta^®barley) kernels were investigated. In order to address the impact of thermal processing on these effects, kernels were roasted (150-180 °C, approx. 20 min), digested and fermented using an In Vitro human digestion model. Concentrations of short-chain fatty acids (SCFA) and ammonia were determined in fermentation supernatants (FS). Growth inhibition, apoptosis, DNA integrity and gene expression of catalase were analyzed in LT97 colon adenoma cells. Concentrations of SCFA, particularly butyrate, were higher in oat/barley FS (2.2-fold, on average), while ammonia levels were significantly lower (0.7-fold, on average) than in the fermentation control. Treatment of LT97 cells with FS of oat/barley kernels led to a significant time- and dose-dependent growth reduction, a significant increase in caspase-3 activity and enhanced levels of catalase mRNA, without exhibiting genotoxic effects. In general, the results indicate a chemopreventive potential of In Vitro fermented oat and waxy winter barley mediated mainly by growth inhibitory and apoptotic effects, which are preserved after thermal processing.

Nutraceutical profiling of surimi gel containing β-glucan stabilized virgin coconut oil with and without antioxidants after simulated gastro-intestinal digestion

Surimi gels containing β-glucan stabilized virgin coconut oil (VCO) were subjected to simulated gastrointestinal digestion and the resulting digest was analyzed for nutraceutical properties. β-glucan stabilized VCO nanoemulsion (βG-V-N) remarkably improved antioxidant activities of the surimi digest. When epigallocatechin gallate (EGCG) was added in nanoemulsion, the surimi digest showed the highest antioxidant activities. Antidiabetic activity of the digest was also improved by the addition of βG-V-N comprising EGCG. Nevertheless, the addition of βG-V-N lowered ACE inhibitory activity of surimi digest. The surimi digest from the gel added with βG-V-N possessed an inhibitory effect on five cancer cell lines including HEK (Human embryonic kidney 293 cells), MCF-7 (breast cancer cell line), U87 (human glioma), HeLa (human cervical cancer), and IMR-32 (human neuroblastoma), regardless of EGCG or α-tocopherol incorporated. This study demonstrated that surimi gel supplemented with βG-V-N in the presence of EGCG exhibited nutraceutical potential and could be used as a functional food.

Chemopreventive effects of raw and roasted oat flakes after in vitro fermentation with human faecal microbiota

The aim of the present study was to analyse chemopreventive effects of oat flakes under consideration of processing. Thin and thick flakes were roasted and subjected to an in vitro digestion and fermentation. Fermentation supernatants (FS) were characterised and chemopreventive effects were analysed in LT97 colon adenoma cells. Compared to the fermentation control, pH values were decreased (from pH 6.3 to pH 5.0) and concentrations of SCFA, in particular butyrate, were increased in oat FS (2.6-fold, on average). Ammonia levels were not altered. Oat FS significantly decreased cell growth time- and dose-dependently. Caspase 3 activity was significantly increased (9.7-fold, on average). Oat FS slightly increased the mRNA expression of CAT (2.0-fold), SOD2 (1.7-fold) and GSTP1 (2.8-fold), on average, while GPX1 mRNA (0.3-fold) was decreased. The results indicate a chemopreventive potential of in vitro digested oat flakes regarding colon cancer development mediated mostly by growth inhibition and apoptosis, unaffected by roasting.

Development of a whey protein spread enriched with β-glucan: an alternative for whey valorization

BACKGROUND

Innovative approaches to combine whey with other ingredients and the use of new techniques in product development should be explored to meet consumers' needs and expectations. However, the question arises here of whether whey protein could be used as a suitable food matrix for supplementation with β-glucan, an attractive glucose polymer and a physiologically functional component. The present study addresses the challenge associated with the design and characterization of whey protein spread as a substrate for β-glucan delivery. The results are discussed on the basis of physical-chemical and microbiological characteristics, which are subsequently linked to its sensorial profile.

RESULTS

A whey protein spread can be developed without the addition of NaCl, with physicochemical characteristics (pH, viscosity), microbiological counts, and sensory acceptance (color, aroma, overall impression) similar to the product with NaCl. This spread can be refrigerated for 28 days. The whey protein spread presented high whey protein content (18.67-19.17 g 100 g^-1 ) and could be a good source of carbohydrates (8.30-8.68 g 100 g^-1 ), with low levels of fat (0.2 g 100 g^-1 ) and lactose (1.56-1.61 g 100 g^-1 ). The sensorial results showed that women would prefer a product with lower salt content.

CONCLUSION

This is the first study to evaluate the development of a whey protein spread enriched with β-glucan, providing results that are of interest for the dairy sector. The combination of whey and β-glucan can be explored industrially as a whey protein spread, with satisfactory results for physicochemical, microbiological, and sensory acceptance. © 2019 Society of Chemical Industry.

Study on chemopreventive effects of raw and roasted β-glucan-rich waxy winter barley using an in vitro human colon digestion model

Fermentation supernatants of barley flakes exhibit chemopreventive effects in LT97 colon adenoma cells without impact of roasting.

The properties and formation mechanism of oat β-glucan mixed gels with different molecular weight composition induced by high-pressure processing

High pressure, an emerging nonthermal technology has been widely applied in food product modifications. The effects of oat β-glucan concentration and pressure on the properties of mixed gels with the different ratios of varying molecular weight (MW) β-gulcan induced by HPP were investigated. The results showed that the lowest β-glucan concentration forming a gel was 15% at 200 MPa, while 8% β-glucan was required to form a gel at 500 MPa. The gel intensity and textural properties increased with elevating β-glucan total concentration and pressure. The characteristic compact and smooth mixed gel formed with 12% β-glucan at a ratio of 50:50 at 400 MPa for 30 min. Under this optimal parameters, the mixed solution showed a relatively lower particle size and turbidity, and the hydrogen bonding and electrostatic interaction played the main role during the gel formation process by high pressure. In addition, the core molecular structure of β-glucan was maintained in the mixed gel formed under the optimal parameters.

Beneficial effects of dietary β-glucan on growth and health status of Pacific white shrimp Litopenaeus vannamei at low salinity

An 8-week trial was conducted to evaluate the effect of dietary β-glucan supplement (0, 0.01%, 0.02%, or 0.04%) on growth and health of Pacific white shrimp Litopenaeus vannamei at low salinity of 3 practical salinity unit (psu). The L. vannamei fed 0.02% and 0.04% β-glucan gained more weight and showed higher activities of protease, amylase, superoxide dismutase, and glutathione peroxidase in the intestine than in the control (0% β-glucan). The L. vannamei fed 0.04% β-glucan had a higher condition factor than those fed the control diet. Amylase activity in the hepatopancreas of L. vannamei fed 0.02% β-glucan was higher than those fed the control diet. Dietary β-glucan supplement increased the mRNA expressions of Toll-like receptor, myostatin, immune deficiency or heat shock protein 70, but decreased the mRNA expressions of tumor necrosis factor-α and C-type lectin 3 in both hepatopancreas and intestine. The response of intestine microbiota in L. vannamei fed 0.04% β-glucan was further compared to the control. The 0.04% β-glucan supplement reduced richness and diversity of the intestinal microbial community as indicated by the low values of Chao1 estimator, ACE estimator, Simpson index and Shannon diversity index. Abundances of Bacillus, Chitinibacter, Geobacillus and Vibrio in the intestine increased, while Flavobacterium, Microbacterium and Mycobacterium decreased significantly in L. vannamei fed 0.04% β-glucan compared to the control. This study indicates that dietary β-glucan supplement at 0.02%-0.04% can significantly improve digestibility, antioxidant capacity and immunity in L. vannamei, and thus improve growth performance and survival at low salinity. These beneficial effects of β-glucan probably are related to the dominance of probiotics over potential pathogens in the intestine.

Water-soluble β-1,3-glucan prepared by degradation of curdlan with hydrogen peroxide

This study aims to prepare water-soluble β-1,3-glucan (WSG) by hydrolysis of curdlan with H₂O₂. The hydrolysis conditions were optimised as follows: reaction time of 40 min, H₂O₂ concentration of 2%, temperature of 85 °C and NaOH concentration of 2 mol/l. Under these reaction conditions, WSG yields of up to 83% could be achieved. High-performance liquid chromatographic analysis of WSG revealed a molecular weight of 5268 Da. Fourier-transform infrared spectroscopy confirmed the polysaccharide structure of the WS products. HPLC analysis of the complete hydrolysate of WSG indicated that WSG product consisted of glucose. Taken together, the results demonstrate that preparation of WSG by hydrolysis of curdlan with H₂O₂ is a promising approach with practical significance.

Structural characterization and rheological properties of β-D-glucan from hull-less barley (Hordeum vulgare L. var. nudum Hook. f.)

A high purity of β-D-glucan (80.8%) from hull-less barley (Hordeum vulgare L. var. nudum Hook. f.) (HBBG) was isolated by alkali extraction and multi-precipitation with ethanol. The molecular weight (Mw) of HBBG was determined as 571.4 kDa with a broad distribution (Mw/Mn = 1.6) by using HPSEC. According to methylation and GC-MS analysis, HBBG was identified to be composed of (1 → 4)- and (1 → 3)-glucopyranosyl (Glcp) residues with a ratio of (3.19 ± 0.01). The MALDI-TOF MS and NMR spectroscopy were further conducted to analyze the enzyme hydrolysate released by lichenase digestion on HBBG. The results suggested that HBBG possessed a typical chemical structure of cereal β-D-glucans, namely linear homopolysaccharides formed by β-D-Glcp units via (1 → 4)-linkages and occasionally single (1 → 3)-linkage. The trisaccharide and tetrasaccharide of HBBG accounted for 66.6% of total cellulosyl units, accompanying with a ratio of cellotriosyl to cellotetraosyl units = 1.0, which were significant different from those reported for the other cereal β-glucans. Rheological property analysis revealed that HBBG showed a shear-thinning behavior and thermal resilience during heating-cooling process.

Correlations of Molecular Weights of β-Glucans from Qingke (Tibetan Hulless Barley) to Their Multiple Bioactivities

β-glucans have been considered the major bioactive components in Qingke (Tibetan hulless barley). However, the structure–function relationships of β-glucans from Qingke have seldom been investigated. Whether the bioactivities of Qingke β-glucans are closely correlated to their molecular weights remains unknown. Therefore, in order to explore Qingke β-glucans as functional/healthy food ingredients for industrial applications, and to better understand their structure–function relationships, correlations of molecular weights of Qingke β-glucans to their in vitro binding properties, inhibitory activities on digestive enzymes (α-amylase and pancreatic lipase), anti-inflammatory activities, and anticancer activities were systematically investigated. Results showed that the in vitro binding properties and the inhibitory activities on α-amylase and pancreatic lipase of Qingke β-glucans were positively correlated to their molecular weights. However, the anti-inflammatory activities of Qingke β-glucans increased as their molecular weights decreased. Furthermore, Qingke β-glucans exhibited selectively anti-cancer activities in vitro. Positive and negative correlations of molecular weights to inhibitory effects against A549 cells and MDA-MB-231 cells were observed, respectively. However, the inhibitory effects of Qingke β-glucans against HCT116 cells were not associated with their molecular weights. Results suggested that the molecular weights of Qingke β-glucans significantly affected their bioactivities, which was beneficial for a better understanding of their structure–function relationships. Moreover, results showed that Qingke β-glucans could be further explored as functional/healthy food ingredients for industrial applications due to their multiple health benefits.