Slightly acidic electrolyzed water (SAEW), considered as a broad-spectrum and high-performance bactericide are increasingly applied in the food industry. However, its disinfection mechanism has not ...been completely elucidated. This study aims to examine the disinfection efficacy and mechanism of SAEW on Staphylococcus aureus, compared with that of sodium hypochlorite (NaClO) and hydrochloric acid (HCl). SAEW treatment significantly reduced S. aureus by 5.8 log CFU/mL in 1 min, while 3.26 and 2.73 log reductions were obtained with NaClO and HCl treatments, respectively. A series of biological changes including intracellular potassium leakage, TTC-dehydrogenase relative activity and bacterial ultrastructure destruction were studied following disinfection treatment of S. aureus. The results showed that SAEW decreased the relative activity of TTC-dehydrogenase by 65.84%. Comparing intracellular potassium leakage, the SAEW treatment caused a greater percent of protein leakage (108.34%) than the NaClO (18.75%) or HCl (0.84%) treatments. These results demonstrated the potent impact SAEW had on the permeability of cell membranes. In addition, the ranking of partly agglutinated cellular inclusion formation was HCl > SAEW > NaClO. It appeared that HCl, along with its low pH value, are responsible for most of the cytoplasmic disruptions. Overall, this study demonstrated that the disinfection mechanism of SAEW was disrupting the permeability of cell membrane and the cytoplasmic ultrastructures in S. aureus cells.
•Disinfection mechanism of slightly acidic electrolyzed water was investigated against Staphylococcus aureus.•SAEW treatment had higher disinfection efficacy compared to NaClO and HCl.•SAEW had significantly effects on the permeability of cell membranes.•The ranking of partly agglutinated cellular inclusion formation was HCl > SAEW > NaClO.
•Proanthocyanidins were nanoencapsulated by lecithin using ultrasonic technology.•Optimal parameters were power (270 W), time (5 min), 5% (w/v) lecithin and pH = 3.2.•Ultrasound significantly ...improved the stability and homogeneity of nanoliposomes.•200% increased bioaccessibility of proanthocyanidins after nanoencapsulation.•Nanoliposomes significantly improved the controlled release of proanthocyanidins.
The poor biostability and bioavailability of proanthocyanidins limit their application. In this study, it was hypothesized that encapsulation in lecithin-based nanoliposomes using ultrasonic technology improves the above properties. Based on preliminary experiments, the effects of lecithin mass ratio (1–9%, wt.), pH (3.2–6.8), ultrasonic power (0–540 W), and time (0–10 min) on biostability and bioavailability of purified kiwi leaves proanthocyanidins (PKLPs) were determined. Nanoliposomes prepared optimally with lecithin (5%, wt.), pH = 3.2, ultrasonic power (270 W), and time (5 min) demonstrated a significantly (p < 0.05) improved physicochemical stability, homogeneity, and high encapsulation efficiency (73.84%) relative to control. The PKLPs bioaccessibility during in vitro digestion increased by 2.28–3.07-fold, with a remarkable sustained release and delivery to the small intestine. Similar results were obtained by in vivo analyses, showing over 200% increase in PKLPs bioaccessibility compared to the control. Thus, PKLPs-loaded nanoliposomes are promising candidates for foods and supplements for novel applications.
aquatic product, known as one of the good resources for white meat, has been widely accepted by the consumers due to its high protein, low fat, especially low cholesterol. With the fast development ...of living standards around the world, the consumer demands for high quality, nutrition, safety and freshness of ifshery food are increasing. Thus, high efifcient preservation technologies for aquatic products become particularly important. Superchilling is one of the controlled-temperature preservation technologies for seafood. Aquatic products can be kept in better quality under superchilling conditions. This review introduced the principle and development of superchilling process, mainly focusing on research progresses and technical dififculties of superchilling. The growth mechanism of ice crystals and the feasibility of application of computational lfuid dynamics in analyzing the temperatures variation and ice crystals during superchilling progress were also discussed, which will provide theoretical foundation for its improvement and application.
Fucosylated chondroitin sulfate (fCS) from sea cucumber
(fCS-
) with a chondroitin sulfate type E (CSE) backbone and 2,4-
-sulfo fucose branches has shown excellent anticoagulant activity although ...has also show severe adverse effects. Depolymerization represents an effective method to diminish this polysaccharide's side effects. The present study reports a modified controlled Fenton system for degradation of fCS-
and the anticoagulant activity of the resulting fragments. Monosaccharides and nuclear magnetic resonance (NMR) analysis of the resulting fragments indicate that no significant chemical changes in the backbone of fCS-
and no loss of sulfate groups take place during depolymerization. A reduction in the molecular weight of fCS-
should result in a dramatic decrease in prolonging activated partial thromboplastin time and thrombin time. A decrease in the inhibition of thrombin (FIIa) by antithromin III (AT III) and heparin cofactor II (HCII), and the slight decrease of the inhibition of factor X activity, results in a significant increase of anti-factor Xa (FXa)/anti-FIIa activity ratio. The modified free-radical depolymerization method enables preparation of glycosaminoglycan (GAG) oligosaccharides suitable for investigation of clinical anticoagulant application.
Time to detection experiments (TTD) based on turbidometry using an automatic Bioscreen C is a useful and straightforward method for estimating microbial growth parameters (lag time (λ), growth rate ...(μ) and “work to be done” (h0)) at constant temperature. This study investigated the effects of slightly acidic electrolyzed water (SAEW) and heat treatment on Listeria monocytogenes growth at different recovery temperatures (10 °C, 15 °C, 25 °C, and 30 °C). Similar surviving and sublethally injured L. monocytogenes populations were obtained by heat treatment (55 °C for 10 min) and SAEW treatment (available chlorine concentration of 30 mg/l and ratio of bacteria against SAEW of 8:2 for 30 s). In these experimental conditions, stresses had greater impact on the λ and h0 parameter in comparison with recovery temperature while there was no great change in growth rate under isothermal conditions. Larger λ values and h0 parameters were observed in sublethal-heat injured L. monocytogenes (the maximum λ and h0 parameters are 30.199 h and 1.6492) as compared to SAEW groups (the maximum λ and h0 parameters are 22.634 h and 1.4396). The sensitivity analysis of SAEW and heat treatments on h0 parameter indicated that SAEW treatment showed a higher influence. The collinearity diagnostics of independent variables recovery temperature (T), μ, λ for dependent variable (h0 parameter) demonstrated that T, μ and λ had strong collinearity. In addition, the established secondary models in this study have good performances on predicting the effect of recovery temperature on bacterial growth parameters.
•Growth parameters (λ, μ, h0) of sublethal Listeria monocytogenes were measured.•The effect of recovery temperature was more pronounced than stress.•Stresses only have marked impact on the lag time of cells.•Secondly models of recovery temperature and growth parameters were developed.
Ultrasound-assisted extraction (UAE) has been widely applied in the extraction of a variety of biologically active compounds including phenolic compounds. However, there is an insufficiency of ...information on simultaneous extraction of these compounds in this area. In the present study, seven phenolic compounds of two families including cinnamic acids (caffeic,
p-coumaric, ferulic, sinapic acid), and benzoic acids (protocatechuic,
p-hydroxybenzoic, vanillic acid) from citrus (
Citrus unshiu
Marc) peels were evaluated by UAE. The effects of ultrasonic variables including extraction time, temperature, and ultrasonic power on the yields of seven phenolic acids was investigated. Results showed that the yields of phenolic compounds increased with both ultrasonic time and temperature increased, whereas the opposite occurred with increasing time at higher temperature to some certain. In the case of 40
°C, the decrease in the yields of some phenolic compounds was observed with increased time, whereas those of other compounds did not significantly declined. Ultrasonic power has a positive effect on the yields of phenolic acids under study. Among all ultrasound variables, temperature is the most sensitive on stability of phenolic compounds. Moreover, when phenolic compounds from citrus peel extracts were subjected to ultrasound process, the benzoic acids were more stable than the cinnamic acids. Meanwhile, the optimal ultrasound condition was different one compound from another. These were partly attributed to both the differently chemical structures of phenolic acids and the combination effects of ultrasonic variables.
Anti-lipopolysaccharide factors are a group of small proteins with broad spectrum antiviral property and antibacterial activity. Herein, we obtained the genomic sequence of the Procambarus clarkii ...anti-lipopolysaccharide factor (PcALF) gene by using polymerase chain reaction to investigate its expression pattern in various tissues and in the immune tissues (Hepatopancreas) following exposure to pathogens. The deduced protein of PcALF was conserved; it displayed the signal peptides and putative lipo-polysaccharide binding domain, particularly the two conserved cysteine amino acid residues at both ends of the domain. The recombinant protein of PcALF was successfully expressed in Escherichia coli and rabbit anti-PcALF polyclonal antibodies were prepared. The qRT-PCR analysis showed unequal distribution of PcALF transcript in the examined tissues, however the transcript level was greatest in hepatopancreas. The challenge with peptidoglycan (PGN), lipo-polysaccharide (LPS) and Poly I:C significantly enhanced expression level of PcALF in hepatopancreas when compared with the PBS control. RNA interference of PcALF affected the mRNA expression levels of immune-related genes. Taken together, our data suggested that PcALF is an inducible protein and could play a key biological role in the innate immune defense of P. clarkii.
•A new anti-lipopolysaccharide factor from Procambarus clarkii (PcALF) was identified and characterized.•Transcripts and expression levels of PcALF in the hepatopancreas were detected after LPS, PGN and Poly I:C challenge.•The recombinant protein (rPcALF) was successfully expressed in Escherichia coli cells.•RNA interference of PcALF influenced the expression of immune-related genes.
Slightly acidic electrolyzed water (SAEW) has been recognized as an effective bactericidal agent with free chlorine, but its limitations include its instability and its great dependence on equipment. ...Newly developed circulating electrolyzed water (CEW) with a higher available chlorine concentration (ACC) could successfully overcome these limitations. In this study, SAEW (ACC of 20 mg/L), CEW1 (ACC of 200 mg/L), and CEW2 (ACC of 20 mg/L) were evaluated for changes in properties (pH, oxidization reduction potential ORP, and ACC) during storage in open or closed glass bottles under light or dark conditions at room temperature (approximately 20 °C) and after washing pork and lettuce. Additionally, the washed pork and lettuce were evaluated for total viable counts, pH and general appearance. The results showed that CEW1 with a higher ACC has better stability than SAEW with a lower ACC for the storage and washing experiments, and CEW still remained stable after dilution with distilled water. The property indices of EW were greatly affected for the pork‐washing experiments compared with the lettuce‐washing experiments, probably due to the existence of alkaline and organic materials on the surface of pork. Furthermore, EWs were more effective for inactivating microbes in lettuce than in pork, while there was no significant difference in tissue pH and the general appearance of pork and lettuce. These findings indicated that CEW with a higher ACC shows potential for reducing foodborne pathogens on pork and lettuce without effects on their physicochemical characteristics, and it can be applied in a diluted form.
Practical Application
Electrolyzed water is now well known as an effective antimicrobial agent. However, it has not been widely applied due to its unstable properties. This study could provide valuable information regarding the storage conditions to maintain EWs for a longer shelf life. This study demonstrated that CEWs with higher chlorine concentrations are more stable.
Squid is considered as a healthy food by consumers because of its high nutritive value. However, it is easily decay caused by microbial contamination. This study aimed to investigate the effect of ...slightly acidic electrolyzed water ice (SAEW-ice) on preservation of squid. Five groups (untreated with ice (A), squid placed on the tap water (TW) ice (B) or SAEW ice (C), squid placed in the TW ice layers (D) or SAEW ice layers (E)) were conducted to evaluate the changes of sensory properties, microbial loads, pH value, peroxide value (POV), thiobarbituric acid (TBA) and total volatile basic nitrogen (TVBN) contents during the shelf life tests. The results showed that SAEW-ice was more efficient at maintaining the squid quality during storage than TW-ice. The total bacterial counts were significantly reduced by 1.46 ± 0.10 log10 CFU/g treated by SAEW-ice and maintained relatively slow microbial growth during storage. It was also observed that SAEW-ice treatment delayed the appearance of browning and softening. Furthermore, SAEW-ice treatment also inhibited the increase of POV and maintained relatively low TBA and TVBN contents. These data indicated that SAEW-ice had the potential to ensure the microbial safety and control the quality deterioration of squid during storage, which could be a new approach worthy of further investigation.
•Compared the effect of SAEW-ice and TW-ice on the preservation of squid.•The effect of SAEW-ice was more pronounced than TW-ice and without ice treatment.•The way of placing in the ice slightly enhanced the effectiveness of SAEW-ice.
Antibacterial effect of cinnamon oil combined with thyme or clove oil was studied in this paper. Agar dilution method was used to determine the minimum inhibitory concentrations （MICs） of the ...essential oils （EOs） of cinnamon, thyme, and clove oil against three Gram-positive bacteria （Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus）, and two Gramnegative bacteria （Escherichia coli and Salmonella typhimurium）. The results showed that cinnamon was a promising antibacterial substance with MIC ranged from 0.1 to 0.4 μL mL^-1 for the five bacterial species. Agar dilution checkerboard method was used to test the combined antibacterial effect of cinnamon oil with thyme or clove oil. Combination of cinnamon and thyme oil showed an additive effect against all selected bacteria, and combination of cinnamon and clove oil displayed an additive effect against B. subtilis, B. cereus, S. aureus, and an indifferent effect against E. coli and S. typhimurium. Furthermore, gas chromatography-mass spectrometry （GC-MS） measurement was used to analyze the components of the EOs, and the main components of cinnamon, thyme, and clove were cinnamaldehyde, thymol, carvacrol and p-cymene, and eugenol, respectively.
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