Qiuhui Hu

Profile and distribution of soluble and insoluble phenolics in Chinese rapeseed (Brassica napus)

The profile and distribution of soluble and insoluble phenolics in 10 rapeseed (Brassica napus) varieties were studied in this work. Photometric results show that the soluble total phenolic content (TPC) and the total tannin content (TTC) of rapeseed dehulled flours are much higher than those of rapeseed hulls. Soluble and insoluble phenolics were further analysed by HPLC/MS and MS/MS. For soluble phenolics, seven species were identified and quantified. Sinapine was found to be the major component in both defatted rapeseed hulls and dehulled flours, with its content ranging from 0.93 to 1.76 mg/g and 15.65 to 21.88 mg/g, respectively. For insoluble phenolics, eight phenolic acids were detected in rapeseed hulls, while only two of them were found in their dehulled flours. Sinapic acid and protocatechuic acid, which also were found in dehulled flours, were identified as two major insoluble phenolics in rapeseed hulls. Insoluble TPCs in defatted rapeseed hulls and dehulled flours were shown to be in the similar range.

Effect of stable antimicrobial nano-silver packaging on inhibiting mildew and in storage of rice

Antimicrobial nano-silver packaging (ANP) films were synthesized by blending polyethylene and highly dispersed Ag/TiO2 powder for rice storage at 37°C and 70% relative humidity. ANP films were characterized by X-ray diffraction and silver migration. The antimicrobial activity of the films was assessed on Aspergillus flavus (A. flavus) by scanning electron microscope and total plate count, and the storage quality of rice was evaluated by texture analyzer and rapid viscosity analyzer. The results show that ANP had a quite beneficial effect on the antimildew and physicochemical property as compared to the normal PE packaging. During 35days storage, the migration of silver into rice was not evident. A lower microbial population is observed on ANP that should be attributed to the presence of Ag/TiO2. Furthermore, rice packed by ANP shows an enhanced quality with regards to texture and pasting properties. Therefore, ANP is a promising packaging material for rice storage.

Identification of flavonoids from Flammulina velutipes and its neuroprotective effect on pheochromocytoma-12 cells

The flavonoids from Flammulina velutipes (FVF) were isolated and the chemical composition of FVF was identified by high-performance liquid chromatography/mass spectrometry (HPLC/MS). The antioxidant activity and the neuroprotective effect against H2O2-induced pheochromocytoma-12 cells (PC12) cytotoxicity of FVF was investigated. Six flavonoids from FVF were identified as arbutin, epicatechin, phillyrin, apigenin, kaempferol and formononetin. Obtained results suggested that FVF possesses strong antioxidant properties in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities as well as reducing power. Pretreatment of PC12 cells with FVF significantly increased the survival rate of cells, glutathione level and superoxide dismutase activity. Conversely, the pretreatment reduced the release of lactate dehydrogenase and the accumulation of both intracellular reactive oxygen species and malondialdehyde. These findings collectively suggested that the protective effects of FVF against H2O2-induced neurotoxicity in PC12 cells as well as the potential for neuroprotection of FVF could be due to its antioxidant action.

Development, physiochemical characterization and forming mechanism of Flammulina velutipes polysaccharide-based edible films

Edible films of Flammulina velutipes polysaccharide were prepared and characterized in terms of rheological, optical, morphologic, mechanical and barrier properties to evaluate their potential application in food packaging. Results suggested that FVP film prepared by the solution of 1:150 (w/v) had the optimal mechanical property, smooth and uniform surface, and good barrier property to water (37.92±2.00gmm/m(2)hkPa) and oxygen (37.92±2.01meq/kg). The capacity of film-formation might be related to inter-molecular and intra-molecular hydrogen bonds of FVP and formation of β-glycosidic bonds during the process of film-formation. These findings will contribute to a theoretical basis for the development of FVP film in food packaging.

Protective effects of Se-containing protein hydrolysates from Se-enriched rice against Pb2+-induced cytotoxicity in PC12 and RAW264.7 cells

The protective capacity of Se-containing protein hydrolysates with molecular weight below 1kDa (SPHs-3), against Pb(2+)-induced damage in PC12 and RAW264.7 cells, was investigated in this study. The cell viability, levels of reactive oxygen species (ROS), lactate dehydrogenase (LDH), superoxide dismutase (SOD), nitric oxide (NO), malondialdehyde (MDA) and glutathione (GSH) in cell were analyzed. Results showed that 100μg/ml of SPHs-3 pretreatment could significantly increase cell viability by 24.9% and 23.0% in Pb(2+)-treated PC12 and RAW264.7 cells, respectively (P<0.01). The levels of ROS, NO, LDH and MDA were reduced by 32.2%, 68.2%, 79.7% and 73.7% in 100μg/ml SPHs-3 pretreated PC12 cells, respectively (P<0.01). SPHs-3 pretreatment was also associated with increases of SOD activity and GSH content in cells. In conclusion, SPHs-3 could protect cells against Pb(2+)-induced cytotoxicity, suggesting that Se-enriched rice may be a feasible candidate to improve health standard of the Pb(2+)-pollution population.

Protection mechanism of Se-containing protein hydrolysates from Se-enriched rice on Pb2+-induced apoptosis in PC12 and RAW264.7 cells

This study aimed to investigate the protection mechanism of Se-containing protein hydrolysates (SPH) from Se-enriched rice on Pb2+-induced apoptosis in PC12 and RAW264.7 cells. Results showed that SPHs could alleviate Pb2+-induced morphological changes of apoptosis and the loss of mitochondrial transmembrane potential in both cell types. Besides this, SPHs could significantly reduce the activation of caspase-3, -8, -9 induced by Pb2+, reverse the Pb2+-induced upregulation of Bax and release of cytochrome C, and downregulate Bcl-2 in cells. HPLC-ICP-MS and SEC-HPLC assays showed that SPHs were low molecular weight peptides (229.4-534.9Da), and the major Se species found in SPHs was SeMet. Taken together, these findings suggested that SPHs could possibly protect the cells against Pb2+-induced apoptosis via a caspase-dependent mitochondrial pathway, and the primary effective constituents in SPHs were SeMet and Se-containing peptides, suggesting that SPHs might be a novel potential candidate to improve the health of people with Se deficiency or in Pb-contaminated areas.

Simultaneous determination of pesticide residues and antioxidants in blended oil using a liquid-liquid extraction combined with dispersive solid phase extraction method

This article developed a method to detect two antioxidants (butylated hydroxyl anisole (BHA), butylated hydroxyl toluene (BHT)) and twelve pesticides (dichlorvos, pirimicarb, prothiofos, fenitrothion, ethoprophos, malathion, beta-Cypermethrin, profenofos, diazinon, propoxur, procymidon, captan) in blended oil samples after their extraction simultaneously. The establishment of the method was based on two-step process of screening and optimization experiment design. With a Plackett-Burman (PB) design, significant parameters were found by screening experiment and single factor experiment accompanied by a central composite design (CCD) experiment were used to make important parameters optimal. The coefficients of determination (r2) was between 0.9931 and 0.9996 while the limits of quantification (LOQs) and limits of detection (LODs) were found in scope of 0.002-0.04mg·kg-1 and 0.0006-0.0012mg·kg-1. Recovery values of analytes were above 74%, at the same time the relative standard deviations (RSDs) under 10% at the concentrations ranging from 0.05mg·kg-1 to 0.20mg·kg-1. To sum up, this method with shorter time and fewer consumption of reagents could be employed in various occasions to detect antioxidants and pesticides.

Effect of nanocomposite packaging on postharvest senescence of Flammulina velutipes

A polyethylene based packaging material containing nano-Ag, nano-TiO2, nano-SiO2, and attapulgite has been prepared. The effect of nanocomposite packaging material (Nano-PM) on the senescence of Flammulina velutipes during 15u202fdays of postharvest storage at 4u202f°C and a relative humidity of 90% were analyzed. The results showed that compared with normal packaging material (Normal-PM) and no packaging (No-PM), Nano-PM improved the appearance quality, reduced weight loss and cap opening. The degree of maturity and increase in molecular weight of F. velutipes polysaccharides (FVP) were delayed. The content loss of proteoglycan protein was less and degree of oxidation was lower. The storage with Nano-PM reduced the fibrosis of texture, cellulase activity, the accumulation of hydrogen peroxide (H2O2) and superoxide radical (O2-) by 18.9%, 48.3%, 26.6% and 27.8%, respectively (P <u202f.05). The Nano-PM effectively delayed the postharvest senescence of F. velutipes, hence prolonged its shelf life and increased its preservation quality.

Preparation, characterization, and anti-inflammatory effect of the chelate of Flammulina velutipes polysaccharide with Zn

ABSTRACT The optimal conditions for preparing Zn-Flammulina velutipes polysaccharide (Zn-FVP) chelate were studied by using L9 (34) orthogonal test. The results showed that the optimized conditions for the chelating reaction were as follows: initial concentration of Zn (II), 6u2005mg/mL; ratio of purified polysaccharide (FVPp) to Zn (II), 1:2; chelating time, 8u2005h; and pH, 5. Chelating rate achieved 98.11% under the optimal conditions. Characteristic bands for OH stretching at 3000–3500u2005cm−1 and bands corresponding to C-H variable angle vibration between 1000–1100u2005cm−1 showed some obvious differences for chelation of polysaccharides and zinc. The qualitative spectrum of Zn-FVP indicated the presence of ZnSO4 and the abundant Zn (II) groups were widely present in the chelated samples. The anti-inflammatory effect of FVPp and Zn-FVP on Lipopolysaccharide-stimulated RAW 264.7 cells was evaluated. In the range of 5–50u2005μg/mL, Zn-FVP did not exhibit obvious inhibition of the survival rate of cells. Zn-FVP in noncytotoxic levels showed strong suppressive effect on the inflammatory cytokines (IL-6, TNF-α, INF-γ and NO) and these provided a theoretical base for the anti-inflammatory mechanism of Zn-FVP.

Volatile components of white Hypsizygus marmoreus detected by electronic nose and HS-SPME-GC-MS: Influence of four drying methods

ABSTRACT Four drying methods, viz hot air drying (HD), vacuum drying (VD), microwave-vacuum drying (MVD), and vacuum freeze-drying (FD), were used to dry white Hypsizygus marmoreus (WHM). The volatile and taste components of the dried WHM were comparatively analysed by electronic nose technology (E-nose) and head-space solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GS-MS). Principal component analysis (PCA) showed that E-nose could distinguish fresh WHM and four dried products clearly. Dominant volatile components in fresh WHM were found to be 1-octen-3-ol, 3-octanone, and (E)-2-nonenal. However, it was found that the drying methods caused damage to the 8-carbon compounds (C8), especially to 8-carbon alcohol greatly. For instance, HD produced more ester materials, MVD yielded more aldehyde compounds, FD brought more hydrocarbon products, and VD produced more ketone substances.