Effects of Potassium Chloride and Sodium Chloride on the Thermal Properties of Gellan Gum Gels

The exothermic and endothermic peaks in cooling and heating curves of differential scanning calorimetry (DSC) for gellan gum gels without and with potassium chloride and sodium chloride were analyzed. The gelling and melting temperatures shifted to higher temperatures with increasing gellan and salt concentration in the concentration range of gellan from 0.3 to 2.0% (w/w). The exothermic and endothermic enthalpy increased with increasing gellan and salt concentrations. Cooling DSC curves showed one exothermic peak for samples with salts and at low gellan concentration. Heating DSC curves showed many peaks for all samples except 0.3% (w/w) gellan gum gels. The sol-gel transition of samples was examined numerically by using a zipper model approach. The introduction of cations increases the number of junction zones or zippers and decreases the rotational freedom of parallel links. This makes the structure of junction zones more heat resistant, and increases the elastic modulus of the gel.     

Textural and Rheological Properties of Soy Protein Isolate Tofu-Type Emulsion Gels: Influence of Soybean Variety and Coagulant Type

The contribution of soybean variety and coagulant type to the textural and rheological properties of soy protein isolate (SPI) tofu-type emulsion gels was studied. SPIs from eight soybean varieties were subjected to amino acid and sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) analysis, and results showed that the 11S fraction proteins (r?=?0.833, p?<?0.05) and the ratio of 11S to 7S (r =?0.920, p <?0.01) were positively correlated with the hardness of CaSO₄-induced emulsion gels and glucono-δ-lactone (GDL)-induced gels, with the correlation coefficients of 0.827 (p <?0.05) and 0.893 (p <?0.01), respectively. In the case of microbial transglutaminase (MTGase), strong relations between the content of glutamate (r =?0.886, p?<?0.01) and lysine (r =?0.810, p <?0.05) and gel hardness were found. Rheological data demonstrated that CaSO₄-induced emulsion gel was stiffer with high rigidity but gel induced by MTGase performed better elasticity. The findings of this study are of great importance to further understand the gelation mechanisms of different coagulants and provide useful information for the development of SPI-based filled tofu.     

Influence of Low Acyl and High Acyl Gellan Gums on Pasting and Rheological Properties of Rice Starch Gel

The pasting, viscoelastic, morphological and retrogradation properties of rice starch as affected by low acyl (LA) and high acyl (HA) gellan gums were studied. The additions of both LA and HA gums increased the peak and trough viscosities, while decreased the final and setback viscosities of rice starch paste. The starch-HA mixed pastes exhibited superior viscoelastic properties to the starch-LA pastes as evidenced by their higher storage modulus and lower loss tangent values. The starch-HA system exhibited higher resistance to the stress and more pronounced recovery rate in in-shear structural recovery test. The creep recovery data were well fitted by a 4-element Burger’s model. The shrinkage measurements showed that the addition of both hydrocolloids, especially the HA gellan gum retarded the retrogradation of rice starch gel during cold storage. It was concluded that the addition of LA and HA gellan gums modified the rheology and textural properties of rice starch gel in different ways and interacted under different mechanisms based on their molecular structures.     

Solvation Effects on the Conformational Behaviour of Gellan and Calcium Ion Binding to Gellan Double Helices

The contribution of the presence of solvent to the conformations adopted by disaccharide fragments within the repeat unit of gellan have been studied by molecular modelling techniques. Initial conformational energy searches, using a dielectric continuum to represent the solvent, provided starting geometries for a series of molecular dynamics simulations. The solution behaviour from these simulations was subsequently compared to fibre diffraction data of the potassium gellan salt. The present calculations indicate considerable flexibility of the glycosidic linkages, and this is discussed in relation to its effect on gel formation. One of the fragments was solvated with explicit water molecules. These calculations showed the same conformational behaviour as those simulations conducted in implicit solvent.Finally, a series of molecular dynamics (MD) simulations were performed to study the calcium binding to gellan. The results from this clearly showed a well defined binding site for this ion.Abbreviations MM molecular mechanics - MD molecular dynamics     

Effects of Partial Replacement of Corn with Glycerin on Ruminal Fermentation in a Dual-Flow Continuous Culture System

The objective of this study was to evaluate the effects of partially replacing dry ground corn with glycerin on ruminal fermentation using a dual-flow continuous culture system. Six fermenters (1,223 ± 21 ml) were used in a replicated 3x3 Latin square arrangement with three periods of 10 d each, with 7 d for diet adaptation and 3 d for sample collections. All diets contained 75% concentrate and three dietary glycerin levels (0, 15, and 30% on dry matter basis), totaling six replicates per treatment. Fermenters were fed 72 g of dry matter/d equally divided in two meals/d, at 0800 and 2000 h. Solid and liquid dilution rates were adjusted daily to 5.5 and 11%/h, respectively. On d 8, 9, and 10, samples of 500 ml of solid and liquid digesta effluent were mixed, homogenized, and stored at -20°C. Subsamples of 10 ml were collected and preserved with 0.2 mL of a 50% H₂SO₄ solution for later determination of NH₃-N and volatile fatty acids. Microbial biomass was isolated from fermenters for chemical analysis at the end of each experimental period. Data were analyzed using the MIXED procedure in SAS with α = 0.05. Glycerin levels did not affect apparent digestibility of DM (P _Lin. = 0.13; P _Quad. = 0.40), OM (P _Lin. = 0.72; P _Quad. = 0.15), NDF (P _Lin. = 0.38; P _Quad. = 0.50) and ADF (P _Lin. = 0.91; P _Quad. = 0.18). Also, glycerin inclusion did not affect true digestibility of DM (P _Lin. = 0.35; P _Quad. = 0.48), and OM (P _Lin. = 0.08; P _Quad. = 0.19). Concentrations of propionate (P < 0.01) and total volatile fatty acids (P < 0.01) increased linearly and concentrations of acetate (P < 0.01), butyrate (P = 0.01), iso-valerate (P < 0.01), and total branched-chain volatile fatty acids, as well as the acetate: propionate ratio (P < 0.01) decreased with glycerin inclusion. Linear increases on NH₃-N concentration in digesta effluent (P < 0.01) and on NH₃-N flow (P < 0.01) were observed due to glycerin inclusion in the diets. Crude protein digestibility (P = 0.04) and microbial N flow (P = 0.04) were greater in the control treatment compared with the other treatments and responded quadratically with glycerin inclusion. Furthermore, the inclusion of glycerin linearly decreased (P = 0.02) non-ammonia N flow. Glycerin levels did not affect the flows of total N (P _Lin. = 0.79; P _Quad. = 0.35), and dietary N (P _Lin. = 0.99; P _Quad. = 0.07), as well as microbial efficiency (P _Lin. = 0.09; P _Quad. = 0.07). These results suggest that partially replacing dry ground corn with glycerin may change ruminal fermentation, by increasing total volatile fatty acids, and propionate concentration without affecting microbial efficiency, which may improve glucogenic potential of beef cattle diets.     

Properties,Microstructure and Heat Seal Ability of Bilayer Films Based on Fish Gelatin and Emulsified Gelatin Films

Bilayer films prepared by the lamination of fish gelatin film (GF) and its corresponding emulsified film (EF) with different thickness ratios (7:3, 5:5 and 3:7) were characterized. Bilayer films had the similar tensile strength (TS) to EF (p > 0.05) but showed lower elongation at break (EAB) (p < 0.05). All bilayer films showed the lower water vapor permeability (WVP) but higher oxygen permeability (OP) than GF. Bilayer films had varying ΔE* (total color different), where the highest value was observed in that laminated with higher thickness ratio of EF (p < 0.05). Lower light transmission and higher transparency value were obtained for bilayer films, compared to GF (p < 0.05). Based on scanning electron microscopic (SEM) cross-section micrographs, all bilayer films consisted of two layers. Differential scanning calorimetric (DSC) analysis revealed that the bilayer films had the higher glass transition temperature (T _g) than GF but lower than EF. All bilayer films were heat sealable, however their seal strength and seal efficiency were lower than those of GF (p < 0.05). Therefore, the thickness ratios of GF and EF had a marked effect on the mechanical and barrier properties as well as heat sealing ability of resulting bilayer films.     

Sugar transporters in plants and in their interactions with fungi

Sucrose and monosaccharide transporters mediate long distance transport of sugar from source to sink organs and constitute key components for carbon partitioning at the whole plant level and in interactions with fungi. Even if numerous families of plant sugar transporters are defined; efflux capacities, subcellular localization and association to membrane rafts have only been recently reported. On the fungal side, the investigation of sugar transport mechanisms in mutualistic and pathogenic interactions is now emerging. Here, we review the essential role of sugar transporters for distribution of carbohydrates inside plant cells, as well as for plant-fungal interaction functioning. Altogether these data highlight the need for a better comprehension of the mechanisms underlying sugar exchanges between fungi and their host plants.     

连续炭基肥替代化肥对菜园土壤性质和细菌群落结构的影响

为了解生物炭基肥替代化肥减量施用的田间长期效应,利用定位试验研究连续5 a炭基肥替代化肥对蔬菜产量、土壤理化性质和细菌群落结构的影响。结果表明,连续5 a实施炭基有机肥替代化肥,土壤p H提高了0.13～0.25,土壤有机质、碱解氮和有效磷含量也分别提高了2.1%～62.2%、5.8%～86.0%和0.4%～103.1%,炭基肥替代化肥处理的荠菜(Capsella bursapastoris)产量提高了4.0%～14.8%,但75%替代处理较50%替代处理有所降低。炭基肥替代化肥处理的土壤菌群Sobs、Shannon、Ace和Chao指数均高于单施化肥处理,且均以75%替代处理最高。炭基肥替代化肥显著降低了土壤中硝化菌属(Nitrolancea)、拟无枝酸菌属(Amycolatopsis)、芽单胞菌属(Gemmatimonas)等的丰度,增加了纤维素降解菌菌群(Planifilum、Saccharomonospora)的丰度。芽单胞菌属、Ilumatobacteraceae、Methyloligellaceae等的丰度与土壤全氮、全磷、有机质间具有显著的相关性。可见,连续炭基肥替代化肥...     

Partial Replacement of Ground Corn with Glycerol in Beef Cattle Diets: Intake,Digestibility, Performance,and Carcass Characteristics

The objective of this study was to evaluate the effects of replacing dry ground corn with crude glycerol on intake, apparent digestibility, performance, and carcass characteristics of finishing beef bulls. A completely randomized block design experiment with 25 d for adaptation and 100 d for data collection was conducted, in which 3,640 Nellore bulls (367 ± 36.8 kg; 18 ± 3 mo) were blocked by body weight and assigned to 20 pens. Bulls were randomly assigned to one of four treatments: 0, 5, 10, and 15% (dry matter basis) of crude glycerol in the diet. Initially, 20 bulls were slaughtered to serve as a reference to estimate initial empty body weight, which allowed for carcass gain calculation. Bulls were weighed at the beginning, at two-thirds, and at the end of the experiment for performance calculations. Carcass measurements were obtained by ultrasound. Fecal output was estimated using indigestible neutral detergent fiber as an internal marker. Data were analyzed using the mixed procedures in SAS 9.2 (SAS Institute Inc., Cary, NC). Intake of dry matter, organic matter, and neutral detergent fiber decreased linearly (P < 0.05) with crude glycerol inclusion. However, crude glycerol levels did not affect (P > 0.05) intakes of crude protein, non-fiber carbohydrates, and total digestible nutrients. Digestibility of dry matter, organic matter, neutral detergent fiber, and total digestible nutrients increased quadratically (P < 0.05) with the inclusion of crude glycerol in the diet. Crude glycerol inclusion did not change the intake of digestible dry matter, average daily gain, final body weight, carcass gain, carcass dressing, gain-to-feed ratio, Longissimus thoracis muscle area, and back and rump fat thicknesses (P > 0.05). These results suggest that crude glycerol may be included in finishing beef diets at levels up to 15% without impairing performance and carcass characteristics.     

Investigation of the Effects of Hydroalcoholic Solutions on Textural and Rheological Properties of Various Controlled Release Grades of Hypromellose

Hypromellose (hydroxypropyl methylcellulose, HPMC) matrices are widely used in the formulation of sustained release dosage forms. The integrity and performance of an HPMC matrix formulation depends on rapid hydration and gel formation upon ingestion. Due to the recent alert issued by the Food and Drug Administration regarding the potential negative influence of alcoholic beverages on extended release (ER) formulations, several researchers have evaluated the potential influence of hydroalcoholic media on drug release from ER dosage forms. It has been reported that HPMC matrix formulations do not show “dose dumping” in hydroalcoholic media. The purpose of this study was a fundamental investigation on the effect of hydroalcoholic solutions (0–40% v/v ethanol) on textural and rheological properties of different viscosity grades of neat HPMC, as the functional ingredient within a hydrophilic matrix. In general, hydroalcoholic solutions had little effect on gel formation and mechanical properties of hydrated compacts, while the rheological behavior of HPMC showed dependency on the ethanol content of such solutions.     

Effects of Cellulose Nanofibers Filling and Palmitic Acid Emulsions Coating on the Physical Properties of Fish Gelatin Films

In this preliminary study, fish gelatin films with improved strength and water resistance were prepared from a dispersion of fish gelatin and carboxylated cellulose nanofibrils (CNF) by using the casting method, followed by subsequent coating with palmitic acid emulsion. The surface topography displayed a uniform distribution of the CNF particles in the gelatin films, but aggregation occurred at a CNF dosage of 4 wt% or higher. Due to the reinforcing effect of CNF, a dosage-dependent increase in the Young’s modulus and tensile strength was observed for the CNF-reinforced films. The addition of CNF also led to an obvious increase in thermal stability. Via surface coating, the emulsion at the 60:40 (w/w) ratio of palmitic acid to water showed excellent layer-forming and high adhesion properties, contributing to the significant improvement of water resistance. The enhanced properties of these fish gelatin films would promote their practical applications in edible packaging.     

The Pasting and Gel Textural Properties of Corn Starch in Glucose,Fructose and Maltose Syrup

The pasting and gel textural properties of corn starch in syrup at different concentrations were investigated by Rapid Visco Analyzer (RVA) and Texture profile analysis (TPA) tests. The results showed that the pasting temperatures of corn starch greatly increased, especially at higher sugar concentration. Increasing concentration of syrup caused an increase in peak, trough and final viscosity of corn starch. Peak viscosity and the disintegration rate of starch increased in the following order: fructose syrup> maltose syrup> glucose syrup. Increasing syrup concentration to 13%, 25% and 50% resulted in a lower retrogradation rate than the control. When the maltose syrup concentration increased to 50%, the retrogradation rate decreased to 14.30% from 33.38%. The highest hardness was observed when the syrup concentration was 25%. There was a particular low hardness when the concentration of syrup was 50%. The springiness of starch gels in syrup was similar at different concentrations.     

Preparation,Mechanical and Biological Properties of Inkjet Printed Alginate/Gelatin Hydrogel

3D printing has made remarkable progress in soft tissue reconstruction enabling the custom design of complex material implants with patient specific geometry.Th...     

Effect of Thermal Treatment on the Physicochemical Properties of Emulsion Stabilized by Gelatin from Black Tilapia (Oreochromis mossambicus) Skin

This study investigated the influence of thermal treatment (30 °C to 110 °C, 30 min) on the physicochemical and rheological properties of an emulsion stabilized by black tilapia (Oreochromis mossambicus) skin at pH 4. The protein pattern of tilapia gelatin did not have any significant difference after the gelatin was heated within a temperature range of 30 °C to 70 °C. However, at 90 °C and 110 °C, denaturation occurred where α-, β- and γ-chains of the gelatin were degraded, leading to a concomitant increase in low molecular peptides. The emulsion stability was investigated through a particle size analyzer, zeta potential, microscopic observation and creaming index. The gelatin emulsion was physically stable at 30 °C to 70 °C with a mean droplet size of less than 13 μm. When the heating temperature was increased to 90 °C and 110 °C, the emulsion showed a pronounced increase in droplet size due to coalescence. The gelatin emulsion heated at 90 °C and 110 °C also displayed instability against creaming after storage at room temperature for 7 days. As the heating temperature increased, the gelatin emulsion exhibited a decrease in apparent viscosity and the flow behavior changed from shear thinning to Newtonian. The rheological data also showed that the storage modulus (G′) of emulsion became more frequency dependent as the heating temperature increased, indicating weak droplet interactions. The tilapia gelatin emulsion was physically unstable when subjected to thermal treatment above 70 °C. The data reported in this study provides useful insight into the formulation of acidic food emulsions that require thermal treatment.

     

Alleviation of Liver Dysfunction,Oxidative Stress,and Inflammation Underlines the Protective Effects of Polysaccharides from Cordyceps cicadae on High Sugar/High Fat Diet-Induced Metabolic Syndrome in Rats

This study investigated the protective effects of two polysaccharides (CPA-1 and CPB-2) from Cordyceps cicadae against high fructose/high fat diet (HF/HFD) induced obesity and metabolic disorders in rats. Rats were either fed with normal diet or HF/HFD and treated with CPA-1 and CPB-2 (100 and 300 mg/kg) for 11 weeks. Administration of CPA-1 and CPB-2 significantly and dose dependently reduced body and liver weight, insulin and glucose tolerance, serum insulin and glucose levels. Furthermore, serum and hepatic lipid profiles, liver function enzymes and proinflammatory cytokines (TNF-α, IL-1β and IL-6) were markedly reduced. Additionally, CPA-1 and CPB-2 treatment alleviated hepatic oxidative stress by reducing lipid peroxidation level (MDA) and upregulating glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) activities as well as ameliorated histological alterations through the reduction of hepatic lipid accumulation. These results suggested that the polysaccharides from C. cicadae showed protective effects against HF/HFD induced metabolic disturbances and may be considered as a dietary supplement for treating obesity.