Comparison of the Effects of Different Food-Grade Emulsifiers on the Properties and Stability of a Casein-Maltodextrin-Soybean Oil Compound Emulsion.

The improvement of food-grade emulsifiers in the properties and stability of complex emulsion has attracted much interest. In this study, the effects of six food-grade emulsifiers with a hydrophilic-lipophilic balance (HLB) range of 3.4-8.0 on a casein-maltodextrin-soybean oil compound emulsion were investigated by centrifugal precipitation rate (CPR), emulsifying activity index (EAI), microrheological properties, zeta potential, average particle size, and Turbiscan stability index (TSI). The optimal amounts of added succinylated monoglyceride (SMG) and polyglycerol fatty acid ester were 0.0025% and 0.1% (w/w), respectively, while that of the other four emulsifiers was 0.2% (w/w), according to the CPR. Thereinto, the SMG-stabilized emulsion exhibited the highest emulsifying activity and the lowest viscosity value and possessed the highest stability over 14 days of storage, which was indicated by the lowest TSI value and the smallest change in delta backscattering signal, relative to those of the other groups. Moreover, the emulsion stabilized by SMG displayed better emulsion stability than the control under a range of pH (6.0-8.0) and calcium ion concentrations (0-10 mM), which was attributed to the increased zeta potential value and the decreased average particle size of droplets with the addition of SMG. The present study provides a basic understanding for SMG improving the properties and stability of the complex emulsion.

Immunomodulatory activity and partial characterisation of polysaccharides from Momordica charantia.

Momordica charantia Linn. is used as an edible and medicinal vegetable in sub-tropical areas. Until now, studies on its composition and related activities have been confined to compounds of low molecular mass, and no data have been reported concerning the plant's polysaccharides. In this work, a crude polysaccharide of M. charantia (MCP) fruit was isolated by hot water extraction and then purified using DEAE-52 cellulose anion-exchange chromatography to produce two main fractions MCP1 and MCP2. The immunomodulatory effects and physicochemical characteristics of these fractions were investigated in vitro and in vivo. The results showed that intragastric administration of 150 or 300 mg·kg-·d⁻¹ of MCP significantly increased the carbolic particle clearance index, serum haemolysin production, spleen index, thymus index and NK cell cytotoxicity to normal control levels in cyclophosphamide (Cy)-induced immunosuppressed mice. Both MCP1 and MCP2 effectively stimulated normal and concanavalin A-induced splenic lymphocyte proliferation in vitro at various doses. The average molecular weights of MCP1 and MCP2, which were measured using high-performance gel permeation chromatography, were 8.55×104 Da and 4.41×105 Da, respectively. Both fractions exhibited characteristic polysaccharide bands in their Fourier transform infrared spectrum. MCP1 is mainly composed of glucose and galactose, and MCP2 is mainly composed of glucose, mannose and galactose. The results indicate that MCP and its fractions have good potential as immunotherapeutic adjuvants.

Solution properties and in vitro anti-tumor activities of polysaccharides from longan pulp.

The solution properties of four fractions (LPI-IV) from crude longan pulp polysaccharides (LP3) were analyzed by size-exclusion chromatography combined with laser light scattering, viscometry, complex formation with Congo red, and atomic force microscopy. Their radii of gyration (z)(½) were 43.3, 62.6, 43.2 and 77.3 nm, exponents of (z)(½) = k M(w)(v) were 0.04, 0.50, 0.52 and 0.02, and intrinsic viscosities ([η]) were 9.945, 25.38, 308.2 and 452.1 mL/g, respectively. Moreover, the dependence of [η] on M(w) was established to be [η] = 5.3 × 10⁻²M(w)°·6¹ (mL/g). LPI had both a sphere-like conformation and a triple-helix structure, and LPII-IV existed as flexible chains. LP3, LPI, LPII and LPIII all exhibited direct inhibitory effects on A549, HeLa and HepG2 cells in a positive dose-dependent manner in the range of 50-400 µg/mL. The activities of LPIII, especially the inhibition of HepG2 cell proliferation, were stronger than those of others, which may be partly related to its flexible conformation. The present results support the cancer therapeutic potential of longan polysaccharides.

Phenolic profiles and antioxidant activity of litchi (Litchi Chinensis Sonn.) fruit pericarp from different commercially available cultivars.

Litchi fruit pericarp (LFP) contains significant amounts of phenolics which have been found to exhibit diverse biological activities. The purpose of this work was to determine the varietal differences in phenolic profiles and antioxidant activity of LFP from nine commercially available cultivars. The total phenolic and flavonoid contents ranged from 9.39 to 30.16 mg gallic acid equivalents/g fresh weight (FW) and from 7.12 to 23.46 mg catechin equivalents/g FW, respectively. The total anthocyanin contents ranged from 1.77 to 20.94 mg cyanidin-3-glucoside equivalents/100 g FW. Three anthocyanins, including cyanidin-3-rutinoside, cyanidin-3-glucoside, malvidin-3-glucoside, were detected, and cyanidin-3-rutinoside was the predominant constituent which contributes from 68.8% to 100% to total anthocyanins, The total procyanidin contents ranged from 4.35 to 11.82 mg epicatechin equivalents/g FW. Procyanidin B2, epicatechin, A-type procyanidin trimer, and procyanidin A2 were detected in all nine litchi varieties. The oxygen radical absorbance capacity activities and DPPH radical-scavenging activities ranged from 430.49 to 1752.30 µmol TE/100 g FW and from 4.70 to 11.82 mg/g (IC50), respectively. These results indicate that there are significant differences in phytochemical profiles and antioxidant activity among the tested varieties. Knowing the phenolic profiles and antioxidant activity of LFP of different varieties gives the insights into its potential application to promote health.

Physicochemical characteristics and immunomodulatory activities of three polysaccharide-protein complexes of longan pulp.

Three polysaccharide-protein complexes of longan pulp (LP1-3) were isolated in this work. Their physicochemical characteristics and immunomodulatory effects on splenocytes, natural killer (NK) cells and macrophages in vitro were investigated. The carbohydrate portions of LP1-3 were principally composed of glucose, arabinose and mannose. LP3 displayed the maximal moisture absorption, and the thermal stability of LP2 was obviously higher than that of LP1 and LP3. All of them showed the characteristic polysaccharide and protein bands in the Fourier Transform Infrared (FTIR) spectrum. For a certain dose, all the fractions could significantly stimulate splenocyte proliferation, macrophage phagocytosis against neutral red, and NK cell cytotoxicity against YAC-1 lymphoma cell (P < 0.05). The results demonstrated that the polysaccharide-protein complexes of longan pulp have medical potential as immunotherapeutic adjuvants due to their immunomodulatory activities.

Immunomodulatory activity of polysaccharide-protein complex of longan (Dimocarpus longan Lour.) pulp.

The immunomodulatory function of longan pulp polysaccharide-protein complex (LP3) was investigated in immunosuppressed mice models. Compared with the model control, peroral administration of 100 mgkg⁻¹d⁻¹ LP3 could significantly increase/enhance antibody production against chicken red blood cell (CRBC), concanavalin A (ConA)-induced splenocyte proliferation, macrophage phagocytosis, NK cell cytotoxicity against YAC-1 lymphoma cell, and interferon-gamma (INF-γ) and interleukin-2 (IL-2) secretion in serum (P < 0.05). The immunomodulatory effects, except for those on splenocytes and macrophages (P > 0.05), were also observed in mice administered with 50 or 200 mgkg⁻¹d⁻¹ LP3 (P < 0.05). The beneficial effects of 50-200 mgkg⁻¹d⁻¹ LP3 were comparable to those of 50 mgkg⁻¹d⁻¹ ganoderan. The strong immunomodulatory activity of LP3 confirmed its good potential as an immunotherapeutic adjuvant.

Characterization of recombinant rice quiescin sulfhydryl oxidase and its improvement effect on wheat flour-processing quality.

In this study, recombinant rice quiescin sulfhydryl oxidase (rQSOX) was expressed and characterized, and its performance in flour-processing quality was further evaluated. The purified rQSOX exhibited the highest sulfhydryl oxidation activity (1.96 IU/mg) using dithiothreitol as a substrate, accompanying the production of H2O2. The optimal temperature and pH were 60 °C and pH 8.0 for rQSOX catalyzing oxidation of dithiothreitol. And rQSOX retained 50% of its maximum activity after incubation at 80 °C for 1 h. Moreover, rQSOX supplementation improved the farinograph properties of dough, indicated by the increased dough stability time and decreased degree of softening, and enhanced viscoelastic properties of the dough. Addition of rQSOX (10 IU/g flour) provided remarkable improvement in specific volume (37%) and springiness (17%) of the steamed bread, and significantly reduced the hardness by half, which was attributed to the strengthened gluten network. The results provide an understanding for rQSOX using in flour-processing industry.

Structural features and immunomodulatory activities of polysaccharides of longan pulp.

An aqueous extract of polysaccharides from longan pulp was chromatographed on a DEAE anion-exchange column to yield four fractions (LPI-IV). Immunomodulatory activities of these polysaccharides were also evaluated in vitro. The purified products, neutral polysaccharide LPI, polysaccharide-protein complex LPII and acidic polysaccharides LPIII and LPIV, exhibited conspicuous differences in their monosaccharide composition, molecular mass and glycosidic linkages. Except for LPI, the other three significantly stimulated lymphocyte proliferation in the dose range of 100-400µg/mL compared with the normal control (P<0.05), and might electively stimulate B cells, but not T cells. Furthermore, their stimulations on normal/lipopolysaccharide-induced proliferation and depressions on concanavalin A-induced proliferation could be ordered as LPIII>LPIV>LPII>LPI. All the fractions had the optimal dose of 100µg/mL on enhancing macrophage phagocytosis. Among them, LPII had the considerable yield and activity for exploiting as a potential immunoadjuvant.

Phenolic composition and antioxidant activity in seed coats of 60 Chinese black soybean (Glycine max L. Merr.) varieties.

Phenolics in black soybean seed coat (BSSC) are considered to be responsible for the health benefits of black soybean. BSSCs of 60 Chinese varieties were examined for phenolic contents, anthocyanin profiles, and antioxidant activity. Total phenolic and condensed tannin contents ranged from 512.2 to 6057.9 mg gallic acid equivalents/100 g and from 137.2 to 1741.1 mg (+)-catechin equivalents/100 g, respectively. Six anthocyanins (delphinidin-3-glucoside, cyanidin-3-galactoside, cyanidin-3-glucoside, petunidin-3-glucoside, peonidin-3-glucoside, and malvidin-3-glucoside) were detected by HPLC. Total anthocyanin contents (TAC) were from 98.8 to 2132.5 mg/100 g, and cyanidin-3-glucoside was the most abundant anthocyanin in all varieties, with a distribution of 48.8-94.1% of TAC. Antioxidant properties detected by DPPH, FRAP, and ORAC methods all showed wide variations ranging from 4.8 to 65.3 µg/100 mL (expressed as EC(50)), from 17.5 to 105.8 units/g, and from 42.5 to 1834.6 µmol Trolox equivalent/g, respectively. Sixty varieties were classified into four groups by hierarchical clustering analysis, and group 4 consisting of nine varieties had the highest phytochemicals content and antioxidant activity.