Enzyme-Assisted Ultrasonic Extraction and Antioxidant Activities of Polysaccharides from Schizochytrium limacinum Meal.

Enzyme-assisted ultrasonic extraction (EAUE) was utilized and optimized for extracting polysaccharides from Schizochytrium limacinum meal (SLMPs) via the response surface methodology. The optimal EAUE conditions were determined as follows: enzyme concentration at 5.18%, ultrasonic temperature at 53 °C, ultrasonic duration of 40 min, ultrasonic power at 60 W, and a liquid-to-material ratio of 34 mL/g, achieving a polysaccharide extraction yield of 11.86 ± 0.61%. The purified polysaccharide component, SLMP1-1, isolated using DEAE Sepharose Fast Flow and Sephadex G-100 columns, exhibited potent antioxidant activity. SLMP1-1, with a molecular weight of 25.5 kDa, comprises glucose, mannose, arabinose, and galactose in a molar ratio of 16.39:14.75:1:693.03. 1H NMR analysis revealed the α configuration of SLMP1-1. Antioxidant assessments, including DPPH, ABTS, and ferric ion reduction assays, were detected with inhibitory values at 21.82-82.98%, 38.21-98.46%, and 3.30-20.30% at 0.2-1.0 mg/mL. This confirmed the effective antioxidant capacity of SLMP1-1, which is notably enhanced post oral and gastric digestion. The findings suggest that polysaccharides extracted from Schizochytrium limacinum meal hold significant promise as natural antioxidants.

Screening and Characterization of an α-Amylase Inhibitor from Carya cathayensis Sarg. Peel.

Inhibiting α-amylase can lower postprandial blood glucose levels and delay glucose absorption, offering an effective approach for the development of antidiabetic diets. In this study, an active constituent with inhibitory activity against α-amylase was isolated and purified by bioassay-guided fractionation from Carya cathayensis Sarg. peel (CCSP). The active constituent was identified by NMR and Q-Exactive Orbitrap Mass Spectrometry as 5-O-p-coumaroylquinic acid (5-CQA). 5-CQA possessed strong inhibitory activity against α-amylase, with an IC50 value of 69.39 µM. In addition, the results of the kinetic study indicated that 5-CQA was a potent, reversible, noncompetitive inhibitor against α-amylase. The findings indicate that 5-CQA derived from CCSP has potential as a novel inhibitor against α-amylase, which can help mitigate postprandial blood sugar spikes, making it suitable for inclusion in antidiabetic diets.

Effect of simulated transport vibration on the quality of shiitake mushroom (Lentinus edodes) during storage.

The quality and shelf life of mushrooms are critical to their commercial viability. In this study, the effects of simulated transport vibration on postharvest quality of shiitake mushrooms (Lentinus edodes) were assessed over 12 days of storage. Furthermore, the protective performance of foam cushion material used in packaging during simulated transport was evaluated. Changes in respiration rate, weight loss, browning index, firmness, and malondialdehyde content were measured following vibration treatment. The results revealed that simulated transport vibration contributed to the deterioration of quality of shiitake mushrooms during storage, and the foam cushion material had a protective influence on the maintenance of shiitake mushroom quality. Taken together, our findings suggest that the foam cushion material used in packaging has the potential to improve the quality of shiitake mushrooms and extend their shelf life.

Physiochemical properties of short-term frying oil for chicken wing and its oxidative stability in an oil-in-water emulsion.

In this study, the physiochemical properties of corn oil and its oxidative stability in an O/W emulsion were studied following short-term (120 min) deep-frying of chicken wing. The results showed that the levels of polyunsaturated fatty acids in corn oil decreased after frying. Furthermore, total polar compound content in frying oil was significantly increased to 11.3%. Fourier transform infrared spectra (FTIR) indicated that hydrolysis and oxidation reactions involving triglycerides occurred after frying. Additionally, the increased a* and b* values demonstrated that deep-frying greatly enhanced the intensity of the red and yellow colors of corn oil. Frying reduced the oxidative stability of corn oil in an O/W emulsion as determined by the peroxide value and acid value. These findings indicated that short-term deep-frying of chicken wing deteriorated the quality of corn oil and decreased its oxidative stability in an O/W emulsion. Consumers should consider the potential hazards of food containing short-term deep-frying oil.

Optimization of ultrasonic-assisted enzymatic extraction of polysaccharides from thick-shell mussel (Mytilus coruscus) and their antioxidant activities.

This study aimed to obtain the purified fractions of Mytilus coruscus polysaccharides (MCPs) and investigate their antioxidant activities. MCPs were prepared through ultrasonic-assisted enzymatic extraction optimized by employing the response surface methodology. A single-factor experiment was conducted using the Box-Behnken design to determine the optimum extraction conditions of MCPs. The ultrasonic power was 60 W, liquid-to-material ratio was 30 mL/g, extraction time was 36 min, extraction temperature was 64 °C, enzyme concentration was 3.2%, and polysaccharide extraction yield was 12.86% ±â€¯0.12%. A novel polysaccharide (MCP1-2) was obtained after the purification with AB-8 macroporous resin, DEAE Sepharose Fast Flow, and Sepharose CL-6B column. The molecular weight of MCP1-2 was estimated to be 134.9 kDa according to high-performance gel permeation chromatography. High-pressure liquid-phase chromatography results showed that MCP1-2 contained mannose, rhamnose, glucuronic acid, glucose, galactose, and L-Fuc at a molar ratio of 1.53:1:4.83:81.82:2.36:1.51. Infrared and NMR spectroscopies confirmed that MCP1-2 possessed α- and ß- configurations. The antioxidant activities of MCP1-2 were investigated in vitro, and the results showed that MCP1-2 had good antioxidant activity and can be used as a natural antioxidant in food.

Covalent modification of ß-lactoglobulin by (-)-epigallocatechin-3-gallate results in a novel antioxidant molecule.

ß-lactoglobulin (ß-lg), the predominant protein in bovine whey, was chemically modified by (-)-epigallocatechin-3-gallate (EGCG) to develop a biomacromolecule with antioxidant activity. The EGCG-modified ß-lg was characterized by SDS-PAGE, MALDI-TOF MS and intrinsic fluorescence spectroscopy. The antioxidant properties of EGCG-modified ß-lg was assessed using DPPH radical scavenging activity, iron chelating ability, and inhibition of Cu2+-induced LDL oxidation. SDS-PAGE and MALDI-TOF MS results indicated the dimerization of ß-lg after EGCG modification. Intrinsic fluorescence spectra suggested that EGCG modification caused an alteration in the conformational structure of ß-lg. The results demonstrated that EGCG-modified ß-lg possessed great antioxidant potential in terms of scavenging DPPH radical and chelating ferrous ion. Furthermore, the EGCG-modified ß-lg showed a protective effect against LDL peroxidation. The results indicate that EGCG-modified ß-lg could provide significant health benefits as an antioxidant.

[Chemical constituents from roots of Viburnum setigerum].

This experiment was to study the constituents of the roots of Viburnum setigerum through various column chromatographic techniques. Thirteen compounds were obtained and their structures were identified using chemical and spectroscopic methods as (7αH, 8'αH)-4, 4', 8α-trihydroxy-3, 3', 9-trimethoxy-7, 9'-epoxylignan (1), (7αH, 8'αH)-4, 4', 8α, 9-tetrahydroxy-3, 3'-dimethoxy-7, 9'-epoxylignan (2), alashinol G (3), alashinol F (4), (-)-secoisolariciresinol (5), (7R, 7'R, 8R, 8'S)-3, 3'-dimethoxy-7, 7'-epoxylignane -4, 4', 9, 9'-tetraol (6), (7αH, 8αH, 8'ßH)-4, 4', 7'α, 9-tetrahydroxy-3, 3'-dimethoxy-7, 9'-epoxylignan (7), loganin (8), dihydroquercetin (9), protocatechuic acid (10), 4-hydroxy-3-methoxy-benzoic acid (11), adoxoside (12), and catechin (13). Compound 1 was a new compound. Compounds 3-7 and 11 were reported from the genus Viburnum for the first time. All compounds were separated from this plant for the first time.

Covalent modification of soy protein isolate by (-)-epigallocatechin-3-gallate: effects on structural and emulsifying properties.

BACKGROUND: Soy protein isolate (SPI) has promising applications in various food products because of its excellent functional properties and nutritional quality. The structural and emulsifying properties of covalently modified SPI by (-)-epigallocatechin-3-gallate (EGCG) were investigated. RESULTS: SPI was covalently modified by EGCG under alkaline conditions. SDS-PAGE analysis revealed that EGCG modification caused crosslinking of SPI proteins. Circular dichroism spectra demonstrated that the secondary structure of SPI proteins was changed by EGCG modification. In addition, the modifications resulted in the perturbation of the tertiary structure of SPI as evidenced by intrinsic fluorescence spectra and surface hydrophobicity measurements. Oil-in-water emulsions of modified SPI had smaller droplet sizes and better creaming stability compared to those from unmodified SPI. CONCLUSION: The covalent modification by EGCG improved the emulsifying property of SPI. This study therefore provided an innovative approach for improving the emulsifying properties of proteins. © 2018 Society of Chemical Industry.

Hybrid Fabry-Perot interferometer for simultaneous liquid refractive index and temperature measurement.

A compact and high sensitivity sensor with a fiber-tip structure is proposed and demonstrated for simultaneously liquid refractive index (RI) and temperature sensing. The device is fabricated by inserting a tiny segment of capillary tube between single-mode fibers (SMFs) to form two cascaded Fabry-Perot interferometers (FPIs). The theoretical and experimental results demonstrate that the ambient liquid RI and temperature can be simultaneously determined by the intensity and shift of the resonant wavelength in the reflection spectrum. Our proposed device has the highest RI sensitivity of ~216.37 dB/RIU at the RI value of 1.30; a high spatial resolution owing to its compact size (with dimension <400 µm) makes it promising for high precision bio/chemical sensing applications.