唑螨酯的毒性及研究进展

唑螨酯是一种高效、广谱、非内吸性的苯氧基吡唑类杀螨剂,广泛用于果蔬害螨防治。但近年来因为不合理使用导致残留及安全性问题。笔者综述了唑螨酯的应用、残留、代谢降解及毒性研究进展,以期对后续研究提供参考。     

Enhanced bioactivity of Zanthoxylum schinifolium fermented extract: Anti-inflammatory,anti-bacterial,and anti-melanogenic activity

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Continuous in-line decontamination of food-processing surfaces using cold atmospheric pressure air plasma

This study assessed a continuous in-line decontamination system for food contact surfaces and processing equipment that utilized cold atmospheric pressure plasma (CAP) generated from ambient air. The plasma system was evaluated against two common foodborne pathogens (Salmonella Typhimurium, Listeria monocytogenes) on stainless steel surfaces and against S Typhimurium on commercial poly[ether]-thermoplastic poly[urethane] (PE-TPU) conveyor belts, under simulated conditions of a food-processing facility. A significant level of microbial inactivation was achieved, up to 3.03 ± 0.18 and 2.77 ± 0.71 logCFU/mL reductions of L. monocytogenes and S. Typhimurium respectively within 10 s total treatment on stainless steel surfaces, and a 2.56 ± 0.37 logCFU/mL reduction of S. Typhimurium within 4 s total treatment on the PE-TPU material, according to a procedure based on the well-established EN 13697:2015 industrial protocol. CAP exposure was shown to have a minor impact on the morphology and composition of the treated surfaces. The results indicated that CAP can be applied for effective and continuous disinfection against common foodborne pathogens in food-processing facilities.Industrial relevanceLow temperature plasmas have shown great promise for microbial decontamination, yet industrial uptake of the technology has been limited due to scaling limitations. In this study, a prototype conveyor-based CAP decontamination system was developed and tested under realistic conditions expected within a food-processing facility. The results showed a high level of antimicrobial action against two common foodborne pathogens within a few seconds of CAP exposure, a timescale in line with industrial line processing speeds. Our findings demonstrated that CAP shows great promise for the continuous in-situ decontamination of food contact surfaces, with the potential to mitigate against the costly downtimes incurred in current production line practices implementing chemical disinfectants.     

A reliable and sensitive time-resolved fluorescent immunochromatographic assay (TRFICA) for ochratoxin A in agro-products

Immunochromatographic assays (ICAs) are considered as a suitable diagnostic tool for the detection of mycotoxins. Mycotoxins and especially, ochratoxin A are analytes with more demanding sensitivity requirements. To enhance the sensitivity of current immunochromatographic assays for ochratoxin A (OTA), a novel sensitive ICA was developed in this study. In the assay, microspheres enclosing fluorescent europium (III) [Eu(III)] nanoparticles (EuNPs) were used as a label for OTA monoclonal antibody (OTA-mAb) conjugation. Accordingly, assay was called time-resolved fluorescent immunochromatographic assay (TRFICA). The test strip was composed of three parts: a sample pad, nitrocellulose membrane and an absorbent pad. As for detection, a proper concentration of conjugated microspheres was pipetted into the microtube and sample extract was added to it. Then the strip was inserted into the tube and the fluid flow along the strip. The TRFICA results were obtained in 8 min and read by a portable TRFICA strip reader. The established method allows quantitative determination of OTA with limit of detection as low as 1.0 μg kg⁻¹ in the samples. For validation, spiked samples including wheat, maize, soybean and rice were respectively assayed by TRFICA and a standard high performance liquid chromatography equipped with a fluorescence detector (HPLC-FLD), and good agreement of results was obtained between two methods.     

参薯粉浆酶法水解条件优化与动力学分析

采用液态高温α-淀粉酶水解参薯粉浆,分别通过单因素和正交试验,检测水解液中总还原糖的含量,考察和优化参薯粉浆酶法水解液化过程,并进行酶解反应动力学分析。结果表明：酶解温度90℃、粉浆pH值5.6、参薯粉浆质量浓度40mg/mL、加酶量0.07mL/g、水解时间50min时效果最佳,水解液中总还原糖得率可达到52.95%,米氏常数为Km＝80.84mg/mL,Vm＝1.26mg/(mL ·min)。     

Polycarbonates as temporary adhesives

In this study, a series of polycarbonates were examined as temporary adhesives for wafer-to-wafer bonding. Temporary adhesives require adequate adhesion strength, solvent resistance, and thermal stability during processing of the mated wafers. Polycarbonates were shown to have thermal and chemical stability over a range of values, as well the ability to thermally release the substrates over a range of temperatures. The polycarbonates had adequate adhesion strength for wafer processes, such as polishing. Little or no mechanical force is required to release the wafers after thermal decomposition of the polycarbonate.     

Rheological and viscoelastic properties of corn starch suspension modified by hydrothermal process: Impacts of process intensification

Rheological properties of starch suspension and particle size distribution of treated starch granules under the same conditions (2 bar and 20 min) by direct vapour-heat moisture treatment (DV-HMT), Reduced-Pressurized Heat Moisture Treatment (RP-HMT) and Instantaneous Controlled Pressure Drop Process (DIC) were investigated. DV-HMT and RP-HMT were compared to DIC process in order to determine the role of the vacuum pressure steps before and after injection of live steam on the starch powder. For all treated starches an increase of the particle size of granules was observed, a reduction of the consistency index and of the conservative modulus, compared to the untreated one. This difference becomes so important with increasing of process intensification. Relaxation spectra evaluated from the generalized Maxwell model implied a drift to shorter relaxation time for treated starch suspension than the native one. A decrease in peak intensity H(λ) of relaxation spectra with increase of intensification of processes was observed which conclude that the modified starch suspension moving away from a stable state like gel according to the following order DV-HMT < RP-HMT < DIC. The effect of DIC process seems to be more intense than the two other treatments. This difference can be attributed to the mechanical effect induced by the abrupt decompression towards vacuum after treatment.     

不同辛烯基琥珀酸木薯淀粉酯(OSCS)与壳聚糖质量比对OSCS与壳聚糖-ZnO复合薄膜性能的影响

以壳聚糖和辛烯基琥珀酸木薯淀粉酯（OSCS）为主要成膜基质,甘油为增塑剂、纳米ZnO为增强剂,研究不同OSCS/壳聚糖质量比对薄膜的性能变化。首先制备采用石油醚脱脂和碱法提取木薯淀粉,随后将木薯淀粉改性成OSCS。使用溶液共混法制膜,将壳聚糖溶液、OSCS糊化液及纳米ZnO均质混合,然后超声脱气,烘干成膜。分析不同OSCS/壳聚糖质量比对复合膜力学性能、吸水性、水蒸气透过系数和不透明度的影响。当OSCS/壳聚糖的质量比为1:1时,所得膜的力学性能最佳,抗拉强度为13.85 MPa,断裂伸长率为46.57%。吸水性和水蒸气透过系数随着OSCS和壳聚糖的质量比增加呈现上升的趋势,不透明度呈现先下降后上升的趋势,而OSCS/壳聚糖质量比为1.5:1时不透明度最低为1.56 A/mm。红外光谱证明不同OSCS/壳聚糖质量比的薄膜只是通过简单的物理混合,并无新化学键的产生,并且OSCS/壳聚糖的质量比为1:1时,热性能最佳,玻璃态转化温度最高为102.03 ℃。综合研究,OSCS/壳聚糖的质量比为1:1,整体性能较优,为辛烯基琥珀酸淀粉酯与多糖类复合提供理论基础。     

脱乙酰基魔芋葡甘聚糖理化性质及其对凉皮质构和体外消化的影响

通过傅里叶变换红外光谱、X射线衍射图谱和扫描电子显微镜对不同脱乙酰度的脱乙酰基魔芋葡甘聚糖(deacetylatedkonjac glucomannan,DKGM)进行结构表征,并比较其黏度、持水性、热稳定性的变化;将高脱乙酰度的DKGM(脱乙酰度为72.70%)应用于凉皮制备,分析其对凉皮质构和体外消化特性的影响。结果表明,与KGM相比,DKGM在1 735 cm^-1处的乙酰基特征吸收峰减弱,表面变得粗糙,结晶度增加,热稳定性增加,黏度和持水性随脱乙酰度的增加而下降;添加高脱乙酰度的DKGM后,凉皮的硬度、咀嚼性和黏聚性整体均呈下降趋势,且其体外消化水解率降低,即添加高脱乙酰度的DKGM可提升凉皮口感及抗消化性,可为DKGM与淀粉复配体系在低血糖生成指数食品中的应用提供理论参考。     

Flavor formation of tilapia byproduct hydrolysates in Maillard reaction

The Maillard reaction (MR) of tilapia byproduct protein hydrolysates was investigated for the use of byproduct protein as a food ingredient and to mask its fishy odor and bitter flavor. The flavor differences in tilapia byproduct hydrolysates before and after the MR were analyzed to explore the key flavor precursor peptides and amino acids involved in MR. The results suggested that eight key volatile substances, including 2,5-dimethylpyrazine, 2-pentylfuran, hexanal, octanal, nonanal, (E)-2-decenal, decanal, and 1-octen-3-ol contributed most to the MR products group (ROAV > 1). Ten volatile compounds, including 1-octen-3-ol, hexanal, 2-pentylfuran, 2,5-dimethylpyrazine, methyl decanoate, and 2-octylfuran, were the flavor markers that distinguished the different samples (VIP > 1). The four most consumed peptides were VAPEEHPTL, GPIGPRGPAG, KSADDIKKAF, and VWEGQNIVK. Umami peptides and bitter free amino acids (FAAs) were the key flavor precursor peptide and FAAs, respectively. Overall, the hydrolysates of tilapia byproducts with flavor improved by MR are a promising strategy for the production of flavorings.