A Frontier Review of Nutraceutical Chinese Yam.

Yams are the edible subterranean rhizomes, or tubers, of plants from the genus Dioscorea. There are approximately 600 species of yam plants in the world, with more than 90 of these growing in East Asia. One particular species, Dioscorea opposita Thunb., is highly praised as "the Chinese yam". This distinction arises from millennia of storied history, both as a nutritional food source and as a principal ingredient in traditional Chinese medicine. Among the many cultivars of Dioscorea opposita Thunb., Huai Shanyao has been widely regarded as the best. This review surveyed the historical background, physiochemical composition, applications as food and medicine, and research prospects for the Chinese yam. Modern science is finally beginning to confirm the remarkable health benefits of this yam plant, long-known to the Chinese people. Chinese yam promises anti-diabetic, anti-oxidative, anti-inflammatory, immunomodulatory, anti-hyperlipidemic, anti-hypertensive, anti-cancer, and combination treatment applications, both as a functional food and as medicine.

Characterization, in vitro digestibility, antioxidant activity and intestinal peristalsis in zebrafish of Dioscorea opposita polysaccharides.

The soluble crude polysaccharides from Dioscorea opposita (DOP1 and DOP2) were prepared and characterized. DOP1 and DOP2 obtained carbohydrate (65.71% and 70.18%, respectively), uronic acid (63.71% and 24.84%, respectively) and protein (8.09% and 9.51%, respectively) with molecular weight of 49.24 kDa and 21.62 kDa, respectively. DOP samples were mainly composed of mannose, glucose, galacturonic acid, galactose, and glucuronic acid. The digestibility in vitro, antioxidant activity and intestinal peristalsis effect were then investigated. DOP1 and DOP2 were degraded with decreased molecular weights (39.58 kDa and 18.56 kDa respectively), increased reducing sugar contents (from 16.95% to 19.27%; 12.45% to 15.50% respectively) and free monosaccharides (from 0.89% to 1.42%; 0.90% to 1.14% respectively) after gastric digestion. Both DOP1 and DOP2 were resistant to intestinal digestion, suggesting that DOP samples can be considered as a dietary fiber. Additionally, DOP1 and DOP2 exhibited antioxidant activities positively correlated with the concentration and remained the activities after gastrointestinal digestion in vitro. Furthermore, DOP reduced the fluorescence intensity significantly, indicating DOP can promote the intestinal peristalsis of zebrafish larvae (5 pdf) at 500 µg/mL. Therefore, DOP1 and DOP2 have a better functionality as dietary fibers, including antioxidant activity and intestinal peristalsis promotion, which can be developed as functional foods.

Synthesis and Characterization of a Mixed Nanofertilizer Influencing the Nutrient Use Efficiency, Productivity, and Nutritive Value of Tomato Fruits.

Due to the higher potential for enhancing nutrient use efficiency, nanofertilizer (NF) is crucial in sustainable crop production. Thus, foliar-applied mixed nanofertilizer (MNFf) and commercial fertilizer (CF) into the soil (CFs) were claimed together ([MNFf + CFs]) and comparative nutrient use efficiency (NUE), productivity, and nutritional properties of tomato fruits were investigated. The mixed nanofertilizer (MNF) was prepared in our laboratory and characterized using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared. To avoid the interference of other factors, all the treatments were divided into three groups: (i) blank treatment (no fertilizer), (ii) CF treatment, and (iii) combined [MNFf + CFs] treatment. The vegetative growth and qualitative and quantitative attributes of tomatoes were recorded, and the NUE, total production, and benefit-cost ratio (BCR) were also calculated. In addition, comparative nutritional properties for all treatments were analyzed. The plant's height, stem diameter, root length, photosynthetic pigments, leaf minerals, and qualitative traits of tomato fruits were significantly (p < 0.05) increased by [MNFf + CFs] treatment compared to CFs. The protein, fiber, Fe, Zn, and K contents were significantly (p < 0.05) increased by 23.80, 38.10, 44.23, 60.01, and 2.39%, respectively, with the [MNFf + CFs] treatment as compared to CFs, while the ash and protein contents were both lower than the untreated tomato. Moreover, [MNFf + CFs] treatment has significantly (p < 0.05) increased the antioxidant properties. The NUE, total production, and BCR were also increased by 26.08, 26.04, and 25.38%, respectively, with the same treatment. Thus, [MNFf + CFs] treatment could be a potential alternative for reducing the excess use of CF.

Effects of concentrations, temperature, pH and co-solutes on the rheological properties of mucilage from Dioscorea opposita Thunb. and its antioxidant activity.

The mucilage from Dioscorea opposita (DOM) dispersions presented shear-thinning behaviour that well fitted to the Power Law model. The effects of different concentrations (2%-10% w/v), temperatures (25-80 °C), pH (3.0-9.0), freeze-thaw conditions (thawed at 25 °C and 4 °C), co-salts (KCl and CaCl2) and co-sugars (sucrose, fructose and mannose) on the rheological properties were investigated. Generally, higher concentrations, neutral pH, Ca2+ and sugars increased the viscosity of DOM, while increasing temperature (25-65 °C) had opposite effects. The results suggested that cross-linked networks exist in DOM, and viscosity changes may be related to the ionisation of carboxyl groups, structural changes and enhancement/reduction of molecular interactions. Particularly, Ca2+ could interact with uronic acids of two or more polysaccharide molecules, modify the network-structure through cross-linking with carboxyl groups, and enhance the stronger carboxylate-cation2+-carboxylate interactions. Therefore, DOM is suitable for food applications as thickening or gelling agents in aqueous solutions.

A novel zinc complex with antibacterial and antioxidant activity.

BACKGROUND: In order to enhance the antibacterial activity and reduce the toxicity of Zn2+, novel complexes of Zn(II) were synthesized. RESULTS: A water-soluble zinc-glucose-citrate complex (ZnGC) with antibacterial activity was synthesized at pH 6.5. The structure, morphology, characterization, acute toxicity, antibacterial and antioxidant activities, and in situ intestinal absorption were investigated. The results showed that zinc ion was linked with citrate by coordinate bond while the glucose was linked with it through intermolecular hydrogen bonding. The higher the molecular weight of sugar is, the more favorable it is to inhibit the formation of zinc citrate precipitation. Compared with ZnCl2, ZnGC complex presented better antibacterial activity against Staphylococcus aureus (S. aureus, Gram-positive) and Escherichia coli (E. coli, Gram-negative). CONCLUSIONS: The results of acute toxicity showed no obvious toxicity in this test and in situ intestinal absorption study, suggesting that ZnGC complex could be used as a potential zinc supplement for zinc deficiency.

Characterization and antibacterial activity of edible films based on carboxymethyl cellulose, Dioscorea opposita mucilage, glycerol and ZnO nanoparticles.

The edible films composed ofcarboxymethyl cellulose (CMC), glycerol, mucilage from Chinese yam (DOM)and ZnO nanoparticles (ZnO-NPs), were prepared by a casting method. To evaluate the applicability for food packaging, prepared films were characterised morphological, physical, rheological, mechanical and barrier properties, performed FT-IR, thermal analysis, and finally investigated the antibacterial activity and acute oral toxicity of films. The surface of films presented irregular arrangement with nanoparticles combined in the networks, suggesting the best "CMC to DOM weight ratio" of approximately 1:1 could provide a smooth surface. The films with 2.0 g ZnO-NPs presented antibacterial effects against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria. With the increase of DOM, the antibacterial rate dropped at 400 and 450 µL/mL. The film-forming solutions with higher ZnO-NPs content display shear-thinning properties and liquid-like behaviour. The edible films have a great potential to be used in application in food packaging.

Characterization and antibacterial properties of biodegradable films based on CMC, mucilage from Dioscorea opposita Thunb. and Ag nanoparticles.

The biodegradable films, composed of carboxymethyl cellulose (CMC), glycerol, mucilage from Dioscorea opposita (DOM) and Ag nanoparticles, were prepared by a casting method and characterised including colour measurement, solubility, mechanical and water barrier properties etc. to fit the requirements for food packaging. The films were also analysed by fourier transformed infrared spectroscopy, thermal analysis, scanning electron microscopy, and rheometer etc., meanwhile, the antimicrobial activities and acute toxicity of the films were investigated. The addition of Ag nanoparticles and DOM decreased the tensile strength, water solubility and transparency value, while increased the elongation at break. The functional groups and thermal analysis of films presented no significant differences, and the film-forming solutions showed similar shear-thinning properties. Antimicrobial evaluation revealed that the films achieved significant antibaterial effects against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria. The biodegradable films presented a compact and uniform structure with antibacterial properties and without toxicological responses, which has excellent potential to be applied in food packaging.

Physical properties of mucilage polysaccharides from Dioscorea opposita Thunb.

The physical properties of the mucilage polysaccharides of Dioscorea opposita (DOMP) were investigated in this study. The monosaccharide and amino acid contents, and molecular weight were determined, and morphology was observed. The rheological and emulsifying properties of different concentrations of DOMP were determined at acidic and basic pH (pH 5.0 and 9.0). The glucose and protein contents were 11.05% and 13.39%, respectively, and the average molecular weight was 9062 Da. The DOMP particles were spheres of 0.18 µm diameter, which aggregated in solution. The viscosity of DOMP decreased gradually with increase in shear rate, which was indicative of pseudoplastic characteristics. DOMP showed relatively better emulsification properties than Konjac glucomannan (KGM). The particle size of DOMP decreased and its emulsifying properties improved under both acidic and basic conditions. These results suggested that DOMP can be used as a natural processing agent for improving the mouth-feel of food.

Characterisation comparison of polysaccharides from Dioscorea opposita Thunb. growing in sandy soil, loessial soil and continuous cropping.

This study compared the characterisations of polysaccharides from Chinese yam (Dioscorea opposita Thunb.) growing in sandy soil (SSCY), loessial soil (LSCY) and second-year continuous cropping (CCCY). SSCY contained the highest total polysaccharides (36.55%) and 80.19% glucose, CCCY from sandy soil obtained 24.55% polysaccharides with 43.66% glucose, whereas LSCY contained 27.54% total polysaccharides and 7.94% glucose. The results indicated that Dioscorea opposita from sandy soil may obtain higher level of glucose. CCCY increased the galacturonic acids in yams from 7.03% to 26.19%, which may have been caused by the decrease in soil pH due to continuous cropping. The starches of SSCY and CCCY from sandy soil belongs to C-type, whereas the starch of LSCY from loessial soil has the A-type pattern. The results suggested that the two types of soil and continuous cropping change the compounds and contents of yams, which provide valuable evidences for cropping management and allelopathy effects.

Rapidly screening of α-glucosidase inhibitors from Dioscorea opposita Thunb. peel based on rGO@Fe3O4 nanocomposites microreactor.

Present study aimed to immobilise the α-glucosidase on suitable supports to construct enzymatic microreactors and their subsequent applicability in efficient inhibitor screening from the Chinese Yam (Dioscorea opposita Thunb.) peel. A type of lamellar and porous composites (rGO@Fe3O4) were synthesised with a facile one-step solvothermal method and employed as carriers to construct enzymatic microreactors for screening α-glucosidase ligand from the Chinese Yam peel in league with the high performance liquid chromatography and mass spectrometry (HPLC-MS). The immobilisation amount of α-glucosidase on rGO@Fe3O4 under the optimised conditions was about 40 µg α-glucosidase/mg carriers. Furthermore, the binding capacities of screened inhibitors, 2,4-dimethoxy-6,7-dihydroxyphenanthrene and batatasin I, were 35.6 and 68.2%, respectively. Hence, considering their high screening efficiency and excellent magnetic separation ability, these as-prepared nanocomposite consisting of rGO and Fe3O4 may be potential supports for the enzyme (such as α-glucosidase) immobilisation for rapid α-glucosidase inhibitors screening from the diverse nature resources.

Characterisation of the mucilage polysaccharides from Dioscorea opposita Thunb. with enzymatic hydrolysis.

The mucilage polysaccharides from Dioscorea opposita (DOMP) were extracted and treated with a single/dual enzymatic hydrolysis. The characterisation and viscosity were subsequently investigated in this study. DOMP obtained 62.52% mannose and 23.45% glucose. After single protease and trichloroacetic acid (TCA) treatments, the mannose content was significantly reduced to 3.96%, and glucose increased from 23.45% to 45.10%. Dual enzymatic hydrolysis also decreased the mannose and glucose contents to approximately 18%-35% and 7%-19%, respectively. The results suggest that enzymatic degradation could effectively remove the protein from DOMP accompanied by certain polysaccharides, especially mannose. The molecular weight, surface morphology, viscosity and particle sizes were measured. Enzymatic hydrolysis reduced molecular weight, decreased the viscosity, and increased the particle sizes, which indicates that the characterisations of DOMP samples were altered as structures changed. This study was a basic investigation into characterisation of DOMP to contribute to the processing of food by-products.

Characterization of a Novel Polysaccharide-Iron(III) Complex and Its Anti-Anemia and Nonspecific Immune Regulating Activities.

OBJECTIVE: Dioscorea opposita Thunb is the famous food and traditional medicine in China and it was rich in polysaccharides. Polysaccharides of Dioscorea Opposita Thunb possess immunoregulatory activity, free radical scavenging activity and anti-diabetic activity. A novel polysaccharide- iron(III) complex (CYPIC) was synthesized by using crude polysaccharide extracted from Dioscorea opposita Thunb. The component, structure, morphology and molecular weights of CYPIC were analysed, and the anti-anemia, acute toxicity and nonspecific immune regulating activities of CYPIC were assayed. The results showed that CYPIC could increase red blood cell count (RBC), hemoglobin (Hb), hematocrit (HCT), thymus and spleen index of mice with iron deficiency anemia (IDA). Although the structure and deeper mechanisms of CYPIC should be further studied, CYPIC has the potential to be used as an iron supplement for the treatment of iron deficiency anemia. CONCLUSION: The large scale industrial production was suggested due to the simple preparation processing of CYPIC.

Rheological properties of polysaccharides from Dioscorea opposita Thunb.

This study investigated the chemical components and rheological properties of polysaccharides from Dioscorea opposita Thunb. Graded alcohol precipitation was used to extract Dioscorea opposita polysaccharide samples (S1, S2, S3 and S4). The monosaccharides, amino acid content and molecular weight of each sample were measured and compared. The rheological properties of the polysaccharide samples at different concentrations, temperatures and pH values were studied. The rheological properties of S1, S2 and S3 exhibited pseudoplastic properties and "gel-like" behaviour. The viscosity of S1 was improved with rising temperatures, especially temperatures higher than 80°C, which may be caused by the starch gelatinisation. The acidic and basic environments may break the structures of S3 and S4. However, the extreme conditions improved the viscosity of S1. This work was a basic investigation of the Dioscorea opposita polysaccharides, contributing to the function of yam products and applications of natural thickeners in the food industry.

Chemical components and emulsification properties of mucilage from Dioscorea opposita Thunb.

The properties of mucilage obtained from Dioscorea opposita, generated during industrial manufacturing were investigated in this study. Characteristics such as monosaccharide content, amino acid content, molecular weight, and structural features were measured, whereas morphology was observed using a scanning/transmission electron microscope. Additionally, emulsification properties at different concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) and under acidic and basic pH (5.0 and 9.0) conditions were studied. The results showed that emulsions prepared from mucilage and medium-chain triglycerides presented more effective emulsifying functions and higher stability, especially at low concentrations. Both, acidic and basic conditions improved the overall emulsification properties, which suggested that the isoelectric point of amino acids may be involved in the emulsification properties. The results of this study show that mucilage from Dioscorea opposita can be considered as a sustainable resource of a natural emulsifier obtained from industrial waste.

Emulsification properties of polysaccharides from Dioscorea opposita Thunb.

This study investigated the emulsification properties of polysaccharides from Dioscorea opposita Thunb. Graded alcohol precipitation was used to extract Dioscorea opposita polysaccharides fractions (4 samples) in different ranges of molecular weight. Sample 3 contained more glucose and protein (80.13% and 0.34%, respectively), and molecular weight was approximately 34,790Da, distributing narrowly. The droplet sizes and stabilities of emulsions made of gum arabic (GA) and polysaccharide samples at different concentrations and ratios were measured, specifically the emulsions of GA and medium-chain-triglycerides (MCT); polysaccharides and MCT; and polysaccharides, GA and MCT (1:1:1). The results indicated that sample 2 and 3 had emulsifying properties, and the emulsions made with sample 2, GA and MCT (1:1:1) presented the best emulsification properties. Therefore, polysaccharides of Dioscorea opposita could be utilised as a natural emulsifier that can be improved synergistically with other emulsifiers, such as gum arabic.

Preparation and Characterization of Copolymer Micelles for the Solubilization and In Vitro Release of Luteolin and Luteoloside.

Luteolin (LUT) and luteoloside (LUS) belong to flavonoids with high anticancer potential and were loaded into biodegradable diblock copolymer micelles of methoxy polyethylene glycol-polycaprolactone (mPEG5K-PCL10K), methoxy polyethylene glycol-polylactide-co-glycolide (mPEG5K-PLGA10K), and methoxy polyethylene glycol-polylactide (mPEG5K-PDLLA10K) by a self-assembly method, creating water-soluble LUT and LUS copolymer micelles, respectively. The solubilization formulations of the copolymer micelles were optimized with response surface methodology (RSM). The obtained drug micelles are torispherical under transmission electron microscope (TEM) with an average diameter of about 70 nm. The mPEG5K-PLGA10K exhibited higher loading capacity for LUS which was 4.33%, and LUT- (or LUS)-loaded mPEG5K-PCL10K exhibited a better stability and encapsulation efficiency which was 65.1 and 55.8%, respectively. The in vitro drug release study showed above 47% of LUT was released from micelles at pH 7.4 PBS; however, no more than 35% of LUT was released at pH 6.4 PBS within 24 h. Meanwhile, no more than 30% of LUS was released from micelles whether at pH 6.4 or 7.4 PBS solution within 24 h.

Effects of high-hydrostatic pressure and pH treatments on the emulsification properties of gum arabic.

This study investigated the emulsification properties of the native gums and those treated at high pressure (800 MPa) both at their "natural" pH (4.49 and 4.58, respectively) and under "acidic and basic" pH (2.8 and 8.0) conditions. The emulsification behaviour of KLTA gum was found to be superior to that of the GCA gum. High pressure and pH treatment changed the emulsification properties of both gums. The acidic amino acids in gum arabic were shown to play an important role in their emulsification behaviour, and mechanisms of emulsification for the two gums were suggested to be different. The highly "branched" nature of the carbohydrate in GCA gum was also thought to be responsible for the "spreading" of droplet size distributions observed. Coomassie brilliant blue binding was used to indicate conformational changes in protein structure and Ellman's assay was used to estimate any changes in levels of free thiols present.

Effects of high hydrostatic pressure and chemical reduction on the emulsification properties of gum arabic.

Gum arabic is widely used in the food industry as an additive, both as a thickener and an emulsifier. This study has compared the emulsification properties of two types of gums, KLTA (Acacia senegal) and GCA (Acacia seyal), both in their native/untreated forms and after exposure to high pressure (800 MPa). Further studies were undertaken to chemically modify the disulphide linkages present and to investigate the effects of their reduction on the diffusion of the carbohydrate materials. The emulsification properties of the gum samples were examined by determining the droplet size distribution in a "model" oil-in-water system. Results showed that high pressure treatment and chemical reduction of gums changed the emulsification properties of both gums. The high molecular weight component in arabinogalactan-proteins (AGP/GP), and more "branched" carbohydrates present in gum arabic, may be responsible for the emulsification properties of GCA gum, indicating that the emulsification mechanisms for KLTA and GCA were different.