Anthocyanin effectively scavenges free radicals and protects retinal cells from H<Subscript>2</Subscript>O<Subscript>2</Subscript>-triggered G2/M arrest

It has been previously shown that anthocyanins effectively neutralize free radicals and can act as an antioxidative and anti-aging agent and prevent dementia. In addition, anthocyanins promote expression of rhodopsin, which facilitates night vision impairment, blurred vision, eye fatigue due to physical and mental fatigue, and a loss in rhodopsin has been shown to result from various eye diseases. In this study, the free radical scavenging properties of anthocyanins were evaluated for the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, alkyl radical, and hydroxyl radical using electron spin resonance spectroscopy. The DPPH radical scavenging activity of anthocyanins increased in a dose-dependent manner, with a 50% inhibitory concentration (IC₅₀) value of 2.9 μg/mL. The alkyl radical scavenging activity of anthocyanin was also high, with a IC₅₀ value of 52.2 μg/mL. In addition, the hydroxyl radical scavenging activity of anthocyanins was concentration-dependent. The inhibitory effect of anthocyanins on lipid peroxidation was examined using the ferric thiocyanate and thiobarbituric acid assays. The inhibitory activity of anthocyanins was found to be comparable to that of Vitamin E. In addition, the ability of anthocyanins to reduce oxidative DNA damage was assessed in vitro by measuring the conversion of supercoiled pBR322 plasmid DNA to the open circular form. Also, we have found that anthocyanins’ inhibitory activity of the H₂O₂-induced G2/M phase arrest in ARPE-19 cells. Anthocyanins enhanced the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione S-transferase in ARPE-19 cells. Taken together, the present results demonstrate that anthocyanins possess potent antioxidative activity.     

Electrochemical sensor based on Prussian blue nanorods and gold nanochains for the determination of H<Subscript>2</Subscript>O<Subscript>2</Subscript>

In this paper, a novel electrochemical sensor for the detection of H₂O₂ was proposed based on gold nanochains and prussian blue nanorods (PB@MWCNTs), which were synthesized with multiwall carbon nanotubes (MWCNTs) as a template. With the introduction of MWCNTs and the gold nanochains, the proposed system shows synergy among the Prussian blue (PB), MWCNTs, and the gold nanochains, which amplifies the H₂O₂ sensitivity greatly. A linear range from 1.75 × 10⁻⁶ to 1.14 × 10⁻³ M with a detection limit of 0.5 × 10⁻⁶ M (S/N = 3) and a high sensitivity 300 μA mM⁻¹ cm⁻² for H₂O₂ detection is obtained. Moreover, the sensor exhibits good repeatability and stability.     

Cytoprotective effect of fucoxanthin isolated from brown algae <Emphasis Type="Italic">Sargassum siliquastrum</Emphasis> against H<Subscript>2</Subscript>O<Subscript>2</Subscript>-induced cell damage

In this study, the cytoprotective effect of fucoxanthin, which was isolated from Sargassum siliquastrum, against oxidative stress induced DNA damage was investigated. Fucoxanthin, a kind of carotenoid, was pretreated to the medium and the protective effect was evaluated via 2′,7′-dichlorodihydrofluorescein diacetate, 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide, and comet assays. Intracellular reactive oxygen species were over produced by addition of hydrogen peroxide (H₂O₂), but the production was significantly reduced by the treatment with fucoxanthin. The fucoxanthin strongly enhanced cell viability against H₂O₂ induced oxidative damage and the inhibitory effect of cell damage was a dose-dependent manner. Furthermore, a protective effect against oxidative stress-induced cell apoptosis was also demonstrated via nuclear staining with Hoechst dye. These results clearly indicate that fucoxanthin isolated from S. siliquastrum possesses prominent antioxidant activity against H₂O₂-mediated cell damage and which might be a potential therapeutic agent for treating or preventing several diseases implicated with oxidative stress.     

Cytoprotective effects of polyphenolics on H<Subscript>2</Subscript>O<Subscript>2</Subscript>-induced cell death in SH-SY5Y cells in relation to their antioxidant activities

The cytoprotective effects of five flavonoids (quercetin, rutin, catechin, kaempferol and morin) and four hydroxycinnamic acids (caffeic, ferulic, sinapic and chlorogenic acids) were evaluated by the degree of protection they provided against H₂O₂-induced damage to human neuroblastoma SH-SY5Y cells. All compounds exhibited protection against H₂O₂-mediated cytotoxicity in a dose dependent manner. The concentration required to give a 50% reduction in cell death (EC₅₀ value) were derived from their dose–response relationships. The cytoprotective activities of these phenolic compounds in the order of quercetin > caffeic acid > rutin > chlorogenic acid > catechin > ferulic acid > sinapic acid > morin > kaempferol. The EC₅₀ values of the phenolic compounds were strongly related to their chemical structures. The EC₅₀ values were compared with the antioxidant activities as determined by five different chemically based antioxidant assays [2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), ferric reducing antioxidant power (FRAP) and lipid peroxidation inhibition capacity (LPIC)]. The ability of these phenolic compounds to protect from H₂O₂-induced SH-SY5Y cell death correlated (r ² = 0.85) with their determined LPIC values and weakly (r ² = 0.44) with their ABTS activities. There was no correlation between EC₅₀ values and ORAC, FRAP or DPPH activities. The cytoprotection assay is a more biologically relevant measurement than the chemically defined antioxidant activity assays because it uses human cells as a substrate and therefore accounts for some aspects of uptake, metabolism and location of antioxidant compounds within cells.     

Simultaneous Kinetic and Thermodynamic-Based Assay to Determine the Hydrogen Peroxide (H<Subscript>2</Subscript>O<Subscript>2</Subscript>) Scavenging Activity of Berry Extracts by Using Reaction Calorimetry

This work determines the radical scavenging activity of antioxidants and berry extracts based on the heat generated during their reaction with hydrogen peroxide, under isothermal condition (25 °C). After addition of H₂O₂ to a water solution containing antioxidants, an exothermic heat flow appeared. After an initial damping time, the signal decayed exponentially, following a first-order kinetic. Through an iterative fitting routine, both thermodynamic (ΔH) and kinetic (k) information were achieved. Such approach was applied toward relevant food antioxidants, revealing that the fastest reactivity (k) was for tannic acid > gallic acid > caffeic acid > ascorbic acid. Interestingly, k was inversely correlated with ΔH (r = ?0.96) and with the DPPH test (r = ?0.98). Apparently, strong radical scavengers show faster kinetics and lower ΔH-values, as expected, respectively, from a high reactivity toward peroxyl radical and efficient delocalization capacity. Such approach was finally applied to berry extracts (mixed grape seed and skin; chokeberries; grape seed; goji berries). The resulting ΔH-values were correlated with three indices, namely, total phenol, amperometry, and DPPH test. However, k-values largely deviated from these indices. Such discrepancy was explained considering that none of these indices is a “true” measure of the kinetic of the reaction, but only express an apparent concentration. Conversely, reaction calorimetry provides directly and simultaneously both thermodynamic and kinetic properties of the radical scavenging reactivity of antioxidants or natural extracts.     

Nanoscaled Platforms Based on SiO<Subscript>2</Subscript> and Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Impregnated with Potassium Permanganate Use Color Changes to Indicate Ethylene Removal

The development of novel tools/devices to monitor and oxidize ethylene (C₂H₄), a volatile compound responsible for the ripening and senescence in plants, can be a potential approach to maintain and provide information on the postharvest quality of fruits and vegetables. Here, we propose nanoscaled platforms based on silica (SiO₂) and alumina (Al₂O₃) nanoparticles impregnated with potassium permanganate (KMnO₄) that use color changes to indicate ethylene removal. SiO₂ and Al₂O₃ in the microscale and nanoscale were impregnated with varied concentrations of KMnO₄ through a simple mixture route, which systems were capable of oxidizing the ethylene in a closed atmosphere under relative humidity of 45, 60, 75, and 90%. Ethylene removal and color changes were monitored using gas chromatography and colorimetry, respectively. The nanoscaled platforms impregnated with KMnO₄ were capable of scavenging ethylene more efficiently for 1-h exposure. Additionally, the color changes experienced by the nanoscaled platforms, arising from the chemical reduction of potassium permanganate, function as an indicator of ethylene removal, which is particularly suitable for postharvest application.     

Acetylcholinesterase‐inhibitor hydrolysates obtained from ‘in vitro’ enzymatic hydrolysis of mannoproteins extracted from different strains of yeasts

In vitro inhibitory activity against acetylcholinesterase (AChE) of peptides obtained by enzymatic hydrolysis of mannoproteins extracted from strains of yeasts was investigated. Yeast mannoproteins were extracted from strains belonging to the genera Brettanomyces, Candida, Pichia and Saccharomyces isolated from dairy products. They were obtained by heat treatment in citrate buffer and purified by affinity chromatography with concanavalin A. Each purified extract was subsequently hydrolysed with proteolytic enzymes (trypsin, pepsin, chymotrypsin and proteinase K) applied individually or in combination, thus generating smaller peptides. Inhibitory activity of the latter against AChE was determined. The molecular weight of mannoproteins, determined by SDS‐PAGE, was between 6.5 and 30 kDa. As regards AChE inhibition, a preliminary screening of all hydrolysed extracts was performed, yielding variable results with 59% maximum inhibition. Subsequently, when inhibitory concentration 50 (IC50) was determined, the extracts showed higher inhibitory activity (between 6.75 and 12.3 mg mL^?1). Results showed that the mannoproteins separated from yeast strains of food origin generated bioactive peptides by enzymatic hydrolysis, which can be of interest to the manufacturing of food with potential functional properties.     

Survey of stable sulfur isotope ratios (34S/32S) of sulfite and sulfate in foods

A study was conducted to determine the natural abundance sulfur isotope ratios in foods containing sulphite preservatives. This involved determining (1) the accuracy and repeatability of sulfur isotope ratios measured using an elemental analyser (EA) coupled to an isotope ratio mass spectrometer (IRMS); and (2) the isotope ratios of 21 samples of commercially available S(IV) oxo-anion compounds, nine samples of S(VI) sulfate salts and the isotope ratios of the sulfate obtained by modified Monier-Williams distillation of SO₂ from 33 retail foods containing sulfite preservatives. The sulfur isotope ratio data for SO₂ recovered from foodstuffs showed a large spread of results, which suggested that the SO₂ derived from sulfite preservatives does not have a distinctive sulfur signature ratio. The range of results (3.1-52.1) overlapped with that found for a range of commercially available sulfite and sulfate reagents commonly used to preserve food (sulfites 2.5-13.7, sulfates 10.0-16.9). Whilst the variability in isotope ratios originated from the food samples themselves, evidence from the analysis of SO₂ gas suggested that isotope fractionation during dissolution, reaction and recovery was also a confounding factor.     

Effects of CaCl<Subscript>2</Subscript> on chemical interactions and gel properties of surimi gels from two species of carps

Effects of CaCl₂ on chemical interactions, textural properties and expressible moisture content of suwari and kamaboko gels from yellowcheek carp and grass carp were investigated. And the correlations between the contents of chemical interactions and physical properties of surimi gels were analyzed. The contents of chemical interactions, especially non-disulfide covalent bonds, disulfide bonds and hydrophobic interactions of suwari and kamaboko gels, varied with addition concentration of CaCl₂ and fish species. Suwari and kamaboko gels from yellowcheek carp exhibited higher breaking force, deformation and gel strength than these from grass carp. Surimi gels (suwari and kamaboko gels) from yellowcheek carp and grass carp exhibited their maximum gel strength when 40 mmol/kg and 100 mmol/kg CaCl₂ was added, respectively. Addition of CaCl₂ at high concentration resulted in low water holding capacity of surimi gels. Correlation analysis indicated that the contents of nonspecific associations, ionic bonds, hydrophobic interactions and sulfhydryl groups exhibited significant correlation with breaking force of surimi gels from yellowcheek carp and grass carp. Additionally, the content of non-disulfide covalent bonds had significant positive correlations with breaking force and expressible moisture of surimi gel from yellowcheek carp.     

Antibacterial and antioxidant properties of <Emphasis Type="Italic">Ramulus Cinnamomi</Emphasis> using supercritical CO<Subscript>2</Subscript> extraction

In this study, crude extracts of Ramulus Cinnamomi from supercritical carbon dioxide under various extraction conditions were examined for their antioxidant and antibacterial activity. The extractions were conducted in the range of 4,000–6,000 psi and 40–50 °C, and the solvent to feed ratio of the extraction was 30. The antibacterial activity was tested on the clinical drug-resistant strains, including 27 Acinetobacter baumannii, 20 Pseudomonas aeruginosa and 2 Staphylococcus aureus isolates by the disk diffusion method. The bioassay results indicated that Ramulus Cinnamomi showed obvious antimicrobial activity against the tested strains. This study also found that increasing the temperature and pressure would increase the yield of the supercritical fluid extraction (SFE), even though the best extraction conditions for antibacterial activity were found to be high pressure and low temperature. The minimum inhibitory concentration (MIC) was determined on the crude extract of Ramulus Cinnamomi, indicating that the crude extracts from supercritical extraction showed better antibacterial activity than those obtained by ethanol extraction. Based on the spectrophotometer and bioassay determination, the antimicrobial constituent was identified to be cinnamaldehyde. Time-kill kinetics and scanning electron microscopy (SEM) were employed to monitor the survival characteristics and the changes in morphologies, respectively, of the test microorganisms in the presence of herbal extracts. Moreover, antioxidant activity was evaluated by scavenging of the free radical DPPH. Extracts of Ramulus Cinnamomi provided 50% inhibition at 2 mg/ml concentration. This study will provide valuable information for extraction of the natural bioactive component, cinnamaldehyde, from Ramulus Cinnamomi by supercritical extraction.     

Hake slices stored in retail packages under modified atmospheres with CO<Subscript>2</Subscript>- and O<Subscript>2</Subscript>-enriched gas mixes

This paper presents the examination of the evolution of biochemical, sensory and microbiological changes occurring in hake slices stored in modified atmospheres containing three gas mixes. It also shows how these changes relate to changes in the concentrations of the gas mixes in the tray packs during storage. At the outset of storage, there was a pronounced drop in the level of CO₂, associated with lowering of the pH and lower scores for texture in sensory inspection. Nevertheless, by the end of storage, CO₂ concentrations had increased. This was associated with growth of Enterobacteriaceae and with more pronounced decreases of O₂, which is consumed by these microorganisms. Weight loss was greater in the atmosphere-stored lots, possibly due to the action of CO₂. TMA-N and TVB-N began to increase on days 10 and 13 of storage and reached the permitted limits on days 17 and 20. Our analyses revealed no appreciable differences of performance between the different gas mixes, possibly because the gas levels were very similar in the various lots throughout storage.     

Effect of CO<Subscript>2</Subscript>/O<Subscript>2</Subscript>-containing modified atmospheres on packed deepwater pink shrimp (<Emphasis Type="Italic">Parapenaeus longirostris</Emphasis>)

The purpose of this study was to analyse the effect of two gas mixtures, containing 40% CO₂/30% O₂/30% N₂ and 45% CO₂/5% O₂/50% N₂, on the microbiological flora (total bacteria count, H₂S-producers microorganisms and enterobacteria) and some biochemical indexes (trimethylamine, total volatile basic nitrogen and biogenic amines) of chilled shrimp. Modified atmosphere packaging (MAP) on shrimps delayed the microbial growth compared to air-packed or iced stored shrimp as well as the trimethylamine and total volatile nitrogen production. However, the production of some biogenic amines seemed to be enhanced during the storage of MAP-shrimp.     

A Novel Colorimetric Detection of <Emphasis Type="Italic">S. typhimurium</Emphasis> Based on Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> Magnetic Nanoparticles and Gold Nanoparticles

Salmonella typhimurium is one of the most common causes of food-associated disease. A colorimetric nanosensor was developed to detect S. typhimurium which was based on the gold nanoparticles’ (GNPs) color change effect. Fe₃O₄ magnetic nanoparticles (MNPs) and GNPs were synthesized separately. Two complementary sequences of the S. typhimurium target DNA were combined to Fe₃O₄ MNPs and GNPs to fabricate capture probes and signal probes. Fe₃O₄ MNPs could achieve the rapid separation and enrichment of target DNA. With the addition of S. typhimurium target DNA sequences, the sandwich-like structures were formed via the DNA hybridization recognition effect. The original good dispersion of GNPs was broken. GNPs showed different degrees of aggregation with different amount of S. typhimurium target DNA. The color changed from red, purple to blue which could be characterized by UV-Vis spectrophotometer. The absorbance spectra of GNPs red shifted constantly with the intensity ratio of A700/A521 changed regularly. There was a linear correlation between the ratio of A700/A521 and the amount of S. typhimurium target DNA. Thus, this was calculated for the basis of quantitative detection of S. typhimurium. This method is simple and rapid with high sensitivity and specificity which could be used to detect actual samples.     

Isolation of <Emphasis Type="Italic">Bacillus subtilis</Emphasis>: screening for aflatoxins B<Subscript>1</Subscript>, M<Subscript>1</Subscript>, and G<Subscript>1</Subscript> detoxification

Aflatoxins are commonly found in cereals worldwide and bring significant threats to the food industry and animal production. The aim of this research was to search for Bacillus subtilis from animals’ guts and soil capable of transforming aflatoxin B₁, M₁, and G₁ simultaneously. In addition, the selected B. subtilis can inhibit the growth of pathogen and resist to unfavorable conditions within simulated gut environments. High-performance liquid chromatography was used to determine the reduction in aflatoxin concentrations. B. subtilis ANSB060 from fish gut had the strongest ability to detoxify toxins, and percentages of aflatoxin B₁, M₁, and G₁ degradation were 81.5%, 60%, and 80.7%, respectively. Moreover, the results implied that the activity of aflatoxins degradation was mainly in the culture supernatant of ANSB060 rather than its cells or cell extracts. And ANSB060 showed antimicrobial activities against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and resistance to the simulated gut environments. This research indicated that the degradation of aflatoxins by ANSB060 could have a great potential in industrial applications.     

乳酸菌亚硝酸盐还原酶制备及酶学性质

研究乳酸菌亚硝酸盐还原酶制备。将细胞破碎、硫酸铵盐析从乳酸菌中提取亚硝酸盐还原酶,经DEAE-52纤维素柱层析、Sephadex G-150凝胶过滤纯化,获得酶制品经SDS-聚丙烯酰胺凝胶电泳法测得相对分子质量约为42kDa。酶学性质分析表明,最适温度30℃,最适pH 5.5,以亚硝酸钠为底物,酶的Km值为120.5ug/mL。     

Thermal studies of wood impregnated with ZnCl<Subscript>2</Subscript>

In this work the thermal behavior of wood impregnated with ZnCl₂ is studied. Impregnation of wood with ZnCl₂ is a treatment used in activated carbon production, and liquefaction and fast pyrolysis of biomass. Frequently, the impregnated wood is dried for several hours at temperatures above 370 K and then it is carbonized. Catalytic pyrolysis occurs, giving rise to a complex set of reactions. A TG/DTA study was done on the raw material, the activated carbon, the pure ZnCl₂ and the intermediate products in order to study the mass and thermal changes occurring. Elemental analysis and SEM analysis were also carried out. An exothermic torrefaction develops during the drying step; the torrefied product is carbonized in an endothermic process that involves ZnCl₂ volatilization. The washed impregnated wood carbonizes through an exothermic process that may involve the decomposition of cellulose, lignin and the solid product of hemicellulose torrefaction.     

蜂蜜中耐高渗透压酵母菌的分离与鉴定

从我国华北地区采集到不同来源的蜂蜜样品13份,对其中耐高渗透压酵母菌进行分离与鉴定,经形态学特征、生理生化特征和26S rDNA基因测序分析,结果表明,分离到的7株耐高渗酵母菌分别鉴定为:菌株A、B为八孢裂殖酵母(Schizosaccharomyces octosporus);菌株C、D、E为蜂蜜接合酵母(Zygosaccharomyces mellis);菌株F、G为暹罗接合酵母(Zygosaccharomyces siamensis)。      

Functionality of selected strains of moulds and yeasts from Vietnamese rice wine starters

The role of starch-degrading mycelial fungi, and the alcohol production and ethanol tolerance of the yeasts isolated from selected Vietnamese traditional rice wine starters were examined, and optimum conditions for these essential steps in rice wine fermentation were determined. Of pure isolates from Vietnamese rice wine starters, mould strains identified as Amylomyces rouxii, Amylomyces aff. rouxii, Rhizopus oligosporus and Rhizopus oryzae, were superior in starch degradation, glucose production and amyloglucosidase activity during the saccharification of purple glutinous rice. A. rouxii was able to produce up to 25%w/w glucose with an amyloglucosidase activity up to 0.6 Ug(-1) of fermented moulded mass. Five yeast isolates identified as Saccharomyces cerevisiae were selected for their superior alcohol productivity. They were able to deplete a relatively high initial percentage of glucose (20% w/v), forming 8.8% w/v ethanol. The ethanol tolerance of S. cerevisiae in challenge tests was 9-10% w/v, and 13.4% w/v as measured in fed-batch fermentations. Optimum conditions for the saccharification were: incubation for 2 d at 34 degrees C, of steamed rice inoculated with 5 log cfu g(-1); for the alcoholic fermentation 4 d at 28.3 degrees C, of saccharified rice liquid inoculated with 5.5 log cfu mL(-1).     

Analysis of vitamin B<Subscript>2</Subscript> using front-face intrinsic beer fluorescence

The study demonstrates an application of front-face fluorescence spectroscopy to characterization of beers. Partial least squares (PLS) regression was used to develop calibration models between emission and synchronous fluorescence spectra of beers, and riboflavin concentration determined by fluorometric titration. The regression models showed a good ability to predict riboflavin concentration.