Extraction, Structural Characterization, Biological Functions, and Application of Rice Bran Polysaccharides: A Review

Changes in the physicochemical properties and structural characteristics of rice bran polysaccharides extracted by specific enzyme cocktail and ultrasound

To maximize insoluble rice bran fiber, rice bran polysaccharides were extracted from it using ultrasound and specific enzyme-assisted methods. Additionally, the specific enzyme cocktail was also produced by Schizophyllum commune cultivated on insoluble rice bran fiber. Based on response surface methodology, the optimal conditions of specific enzyme-assisted extraction were: temperature 42.8 °C, pH 4.3, and enzyme ratio 10.6 mg/g. Then, a three-step method (ultrasound-enzyme-ultrasound assisted extraction) was used for the extraction of polysaccharides. The rice bran polysaccharide yields from three steps were: 5.57 ± 0.34 %, 4.1 ± 0.05 %, and 0.32 ± 0.03 %, respectively, with molecular weight of 266.73, 4.07, and 22.84 kDa. The rice bran polysaccharides exhibited significant differences in the monosaccharide composition, surface morphological, structural characteristics, and antioxidant activities. Additionally, 186 secretory proteins were detected by proteomic analysis in the enzyme cocktail, including complete cellulases and numerous hemicellulases. These findings provide a sustainable, efficient way to extract rice bran polysaccharides with different properties.

Rice bran: Nutritional value, health benefits, and global implications for aflatoxin mitigation, cancer, diabetes, and diarrhea prevention

Rice (Oryza sativa) is a staple food crop with a rich history and significant contributions to global nutrition. This study examines the production of rice and rice bran, focusing on their nutritional profiles, bioactive compounds, and the lack of proper guidelines for aflatoxins and arsenic in rice products. Rice bran's potential as a dietary supplement, particularly in addressing nutrient deficiencies and diseases, is highlighted. Arsenic contamination, a critical food safety issue, is discussed, as their accumulation poses significant risks, including cancer, cardiovascular diseases, and developmental problems. This overview addresses aflatoxin and arsenic contamination, threatening rice's safety and by-products. The structure and characteristics of rice bran, including types of grain polishing, stabilization processes, and toxic elements, are also analyzed. Factors affecting the bioavailability of nutrients, such as pesticide residues and storage conditions, are considered. The review emphasizes the antioxidant properties of rice milling by-products, particularly pigmented rice varieties rich in bioactive compounds. It offers health benefits such as cancer prevention, anti-diarrheal effects, and anti-diabetic properties. This comprehensive analysis underscores rice bran's nutritional and therapeutic value, advocating for its broader utilization to enhance global health and combat nutrient deficiencies.

Structure Characterization and Antioxidant Activity of a Novel Polysaccharide from Bacillus natto Fermented Millet Bran

To improve the high-value application of millet bran, a water-soluble polysaccharide was extracted from fermented millet bran (FMBP) by using Bacillus natto fermentation. A neutral polysaccharide, FMBP-1, was separated and purified from FMBP using an anion exchange column. Its structure and antioxidant activity in vitro were characterized and determined. The molecular weight of FMBP-1 was 1.154 × 104 Da, and its molecular weight distribution was relatively uniform. The monosaccharide composition, FT-IR, methylation, and NMR results indicated that FMBP-1 was only composed of glucose and was an α-(1→4)-D-glucan that branched at O-6 with a terminal 1-linked α-D-Glcp as a side chain. In addition, the antioxidant assays indicated that FMBP-1 possessed certain capacities for scavenging free radicals and reducing power, and this was in a concentration-dependent manner. This research will provide fundamental data regarding the structure-activity relationship of millet bran polysaccharides and provide a theoretical foundation for the high-value utilization of millet bran within the food and pharmaceutical industries.

Effect of γ-irradiation combined with enzymatic modification on the physicochemical properties of defatted rice bran dietary fiber

This study comprehensively examines how combining γ-irradiation and enzymatic modification influences the microstructure and physicochemical properties of dietary fiber (DF) obtained from defatted rice bran. The resulting yields of soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were measured at 13.38 ± 0.40 g/100 g and 52.19 ± 0.97 g/100 g, respectively. The modifications led to a diminish in particle size, an increase in specific surface area, and an improvement in water-holding capacity, oil-holding capacity, swelling capacity, glucose adsorption capacity, and cholesterol adsorption capacity. Furthermore, the modified DF exhibited enhanced anti-digestive properties and probiotic activity. Cluster and principal component analysis results revealed that the modified SDF exhibited superior functional properties. Correlation analysis indicated a noticeable relationship between the monosaccharide composition of DF and its functional characteristics. These findings suggest that γ-irradiation combined with enzymatic modification represents a viable approach for enhancing the quality of rice bran DF.

Polygonum cuspidatum polysaccharide: A review of its extraction and purification, structure analysis, and biological activity

ETHNOPHARMACOLOGICAL RELEVANCE

Polygonum cuspidatum Sieb. et Zucc. is mainly distributed in Shanxi, Gansu, and Sichuan province of China. It is also found in Korea and Japan. Its dried roots and rhizomes are used as medicinal herbs and have been used to treat hyperglycemia and various inflammatory disorders.

AIM OF THE REVIEW

This paper aims to provide an up-to-date review of the developments in the studies involving the extraction and purification, structure analysis, pharmacological effects, and potential applications of polysaccharides obtained from Polygonum cuspidatum. Additionally, the possible future research directions of this plant are discussed.

MATERIALS AND METHODS

This article used "Polygonum cuspidatum polysaccharide (PCP)" and "Polygonum cuspidatum" as the keywords and gathered relevant data on Polygonum cuspidatum using electronic databases (Elsevier, PubMed, ACS, CNKI, Google Scholar, Baidu Scholar, Web of Science), relevant books, and classic literature about Chinese herb.

RESULTS

Excluding irrelevant and repetitive documents, 278 documents were finally included, of which 88 were in Chinese and 190 were in English. The CiteSpace software was used to visualize the trends and keywords in this research field. We concluded that the main extraction methods for Polygonum cuspidatum polysaccharide are water extraction and alcohol precipitation, microwave-assisted extraction, ultrasound-assisted extraction, and microjet extraction. High-performance liquid chromatography and column chromatography are also commonly used in the separation and purification of PCP. PCP has antitumor, immunomodulatory, hypoglycemic, and antioxidant effects. This paper provides an updated and deeper understanding of PCP, serving as a theoretical foundation for the further optimization of polysaccharide structures and the development of PCP as a novel functional material for clinical application.

Interaction of anthocyanins, soluble dietary fiber and waxy rice starch: Their effect on freeze-thaw stability, water migration, and pasting, rheological and microstructural properties of starch gels

This study aimed to investigate the effect of the interaction of black rice anthocyanins (BRA), soluble dietary fiber from extruded rice bran (ES) and waxy rice starch (WRS) on the physicochemical properties of starch gels, including gelatinization properties, rheological properties, freeze-thaw stability, water migration, molecular structure and gel microstructure. The results showed that the pasting temperature (PT) of the mixtures was increased, and the peak viscosity (PV), trough viscosity (TV), final viscosity (FV) and setback viscosity (SV) were significantly reduced when ES and BRA were added to WRS in different proportions (ES:BRA, 4:0, 4:0.4, 4:1, 4:2, 8:0, 8:0.8, 8:2, 8:4). Both ES and BRA could enhance the viscosity of WRS gels, and ES exhibited strong ability on improving the strength of gels. The presence of ES and BRA improved the water retaining capacity of WRS gels, but weakened the freeze-thaw stability. ES, BRA and WRS formed non-covalent bonds (hydrogen bonds) through hydrophilic groups during gelatinization, which improved the gel properties. In addition, the steric hindrance formed by ES and BRA inhibited starch retrogradation. These results might contribute to the development of starch-based food formulations with good quality.

Determination of prebiotic properties of rice bran extract

This research investigated and compared the prebiotic properties of a rice bran extract obtained through commercial xylanase extraction in comparison with water extraction. Prebiotic properties were evaluated by probiotic growth stimulation (Lacticaseibacillus casei and Lactiplantibacillus plantarum) and gastrointestinal pathogen inhibition (Bacillus cereus and Escherichia coli). The rice bran extract obtained with xylanase (RB1) displayed significantly higher total polysaccharide and total reducing sugar contents than those obtained with water (RB2; p<0.05). After extraction for 30 min, RB1 exhibited the highest total polysaccharide and total reducing sugar contents. HPLC (high performance liquid chromatography) analysis revealed that RB1 primarily contained xylose, while RB2 contained less glucose and lacked other sugar derivatives. RB1 proved effective in stimulating the growth of L. casei and L. plantarum, surpassing even inulin (a commercial prebiotic). Furthermore, it demonstrated a high potential for inhibiting the growth of pathogenic B. cereus and E. coli, comparable to inulin. In contrast, RB2 exhibited lower inhibitory capacity against B. cereus and E. coli.

A low-cost efficient online derivatization system for the determination of saccharides by high-performance liquid chromatograph-ultraviolet detector

In this study, a low-cost efficient online derivatization system was developed which allows for the detection of various types of mono- and oligo-saccharides only utilizing high-performance liquid chromatography (HPLC)-ultraviolet detector (UV) system. In the proposed method, phenylhydrazine was used as the derivatization reagent and directly spiked in the mobile phase, allowing for the separation and detection of mono- and oligosaccharides in an accessible instrument system (HPLC-UV). And the online derivatization design of the proposed method has significantly reduced the potential harm of derivatization reagents to the analysts. Furthermore, critical chromatographic parameters were optimized via the Box-Behnken design strategy, culminating in the ideal response for saccharides. Finally, the methodology validation of the proposed method was conducted. The proposed method showed satisfactory linear ranges with acceptable correlation coefficients (R2  > 0.99), outstanding accuracy (Recovery: 95.3%-105.6%), high intra-day precision (relative standard deviation [RSD]: 1.4%-7.1%) and inter-day precision (RSD: 2.0%-7.4%). The robustness and ruggedness of the proposed method were proved as the recovery values in the range of 95.0%-104.6% and 95.1%-104.8% for robustness and ruggedness, respectively. These satisfactory validation results confirm the applicability and reliability of the proposed method for the analysis of saccharides in various complex real-world samples.

Modified rice bran arabinoxylan as a nutraceutical in health and disease-A scoping review with bibliometric analysis

Rice bran arabinoxylan compound (RBAC) is a polysaccharide modified by Lentinus edodes mycelial enzyme widely used as a nutraceutical. To explore translational research on RBAC, a scoping review was conducted to synthesise research evidence from English (MEDLINE, ProQuest, CENTRAL, Emcare, CINAHL+, Web of Science), Japanese (CiNii, J-Stage), Korean (KCI, RISS, ScienceON), and Chinese (CNKI, Wanfang) sources while combining bibliometrics and network analyses for data visualisation. Searches were conducted between September and October 2022. Ninety-eight articles on RBAC and the biological activities related to human health or disease were included. Research progressed with linear growth (median = 3/year) from 1998 to 2022, predominantly on Biobran MGN-3 (86.73%) and contributed by 289 authors from 100 institutions across 18 countries. Clinical studies constitute 61.1% of recent articles (2018 to 2022). Over 50% of the research was from the USA (29/98, 29.59%) and Japan (22/98, 22.45%). A shifting focus from immuno-cellular activities to human translations over the years was shown via keyword visualisation. Beneficial effects of RBAC include immunomodulation, synergistic anticancer properties, hepatoprotection, antiinflammation, and antioxidation. As an oral supplement taken as an adjuvant during chemoradiotherapy, cancer patients reported reduced side effects and improved quality of life in human studies, indicating RBAC's impact on the psycho-neuro-immune axis. RBAC has been studied in 17 conditions, including cancer, liver diseases, HIV, allergy, chronic fatigue, gastroenteritis, cold/flu, diabetes, and in healthy participants. Further translational research on the impact on patient and community health is required for the evidence-informed use of RBAC in health and disease.

The benefits of edible mushroom polysaccharides for health and their influence on gut microbiota: a review

The gut microbiome is a complex biological community that deeply affects various aspects of human health, including dietary intake, disease progression, drug metabolism, and immune system regulation. Edible mushroom polysaccharides (EMPs) are bioactive fibers derived from mushrooms that possess a range of beneficial properties, including anti-tumor, antioxidant, antiviral, hypoglycemic, and immunomodulatory effects. Studies have demonstrated that EMPs are resistant to human digestive enzymes and serve as a crucial source of energy for the gut microbiome, promoting the growth of beneficial bacteria. EMPs also positively impact human health by modulating the composition of the gut microbiome. This review discusses the extraction and purification processes of EMPs, their potential to improve health conditions by regulating the composition of the gut microbiome, and their application prospects. Furthermore, this paper provides valuable guidance and recommendations for future studies on EMPs consumption in disease management.