一氧化氮对绿熟和粉红期番茄采后抗氧化相关酶的影响

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二氧化碳处理对不结球白菜采后品质及过氧化氢清除系统的影响

不结球白菜采后贮藏过程中品质易发生变化。贮藏过程中采用二氧化碳气体（CO2）处理可以延缓采后不结球白菜的衰老进程。减少重要营养物质维生素C（Vc）、可溶性蛋白和叶绿素的损失;CO2处理可抑制过氧化氢清除酶系统中的过氧化氢酶（CAT）、抗坏血酸过氧化氢酶（APx）和过氧化物酶（POD）活力的升高。50％和100％的CO2处理都可延缓采后不结球白菜贮藏过程中品质的下降,而前者的处理效果要优于后者。在室温下（25℃）CO2处理对品质的保持效果较明显．4℃下CO2处理的效果并不明显;在CO2处理的条件下,不同温度处理对品质的改变也不明显,因此不结球白菜采后短期保存可单独采取CO2处理或低温贮藏的方法。     

外源一氧化氮熏蒸处理对番茄采后活性氧代谢的影响

以合作903番茄(Lycopersicon esculenturn)为试材,研究不同浓度NO(20、50μL/L)气体熏蒸处理对番茄呼吸强度、乙烯释放量和SOD、CAT、POD、H2O2、O2-.、MDA等活性氧代谢相关指标的影响。结果表明:外源NO熏蒸处理能够抑制番茄果实贮藏期间的呼吸速率和内源乙烯释放,同时还能够保持番茄果实贮藏过程中SOD、CAT、POD保护酶的活性,抑制组织中的H2O2、O2-.含量的增加,并降低MDA的含量,从而增强番茄果实的抗氧化能力,防止膜脂过氧化,延缓果实的衰老。     

一氧化氮在果蔬保鲜中的应用研究进展

一氧化氮(Nitric oxide,NO)是近年来发现的一种小分子信号物质,其在采后保鲜方面的应用是近年研究的焦点,研究人员发现利用NO短时熏蒸能够增强果蔬的保鲜效果,延长果蔬货价期。对NO应用于果蔬保鲜领域的研究进展情况进行了阐述。     

采后一氧化氮处理对油桃抗软腐病的诱导

以油桃为实验对象,研究了采后NO供体硝普钠(SNP)处理对低温贮藏期间油桃根霉软腐病的控制效果及其机理。研究结果表明硝普钠处理能显著地抑制损伤接种Rhizopus stolonifer的油桃果实软腐病的扩展,其中较低浓度5mmol/L的硝普钠处理效果最好,其病斑直径仅为对照的75.83%。进一步研究表明SNP浸泡处理能显著地提高低温贮藏期间油桃果实组织苯丙氨酸解氨酶(PAL)和过氧化物酶(POD)的活性,且在贮藏后期对组织过氧化氢酶(CAT)和超氧化物歧化酶(SOD)酶活性具有抑制作用,然而对多酚氧化酶(PPO)的活性没有明显的诱导作用。可见一氧化氮是通过改变油桃抗性相关酶的活性来增强果实的抗病性。     

采后一氧化氮处理调控番茄果实茉莉酸类物质合成并提高灰霉病抗性

探讨在番茄果实抗病性诱导过程中一氧化氮对茉莉酸类物质的调节作用。以中蔬4 号绿熟期番茄果实为材料,对其进行不同浓度一氧化氮处理,检测不同处理对番茄果实抵抗病原菌侵染能力、一氧化氮水平、茉莉酸类物质含量及其关键合成酶活性以及抗病酶苯丙氨酸解氨酶活性的影响。结果表明：不同浓度一氧化氮处理均能提高采后番茄果实抵抗病原菌侵染的能力,低浓度一氧化氮供体硝普钠(0.02mmol/L)表现得更为明显;低浓度硝普钠能够促进JAs 含量及脂氧合酶活性的增加,高浓度处理则表现出抑制作用。     

一氧化氮对采后水蜜桃果实衰老和清除自由基酶系影响

为研究一氧化氮(NO)处理对采后水蜜桃果实衰老和清除自由基相关酶的影响,分别采用0、5、10、20和30μL/L的NO气体熏蒸水蜜桃,然后置于20℃下贮藏10 d。结果表明:10μL/L的NO处理可有效地抑制水蜜桃果实软化。对自由基清除酶系影响研究表明,NO处理提高了贮藏期果实超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)、脱氢抗坏血酸还原酶(DHAR)和单脱氢抗坏血酸还原酶(MDHAR)活性,保持了较高抗坏血酸(ASC)含量。因此,适宜浓度(10μL/L)的NO处理能提高桃果实清除自由基酶系能力,抑制膜脂过氧化并保持细胞膜完整性,进而改善贮藏品质。      

Inactivation of Cronobacter malonaticus cells and inhibition of its biofilm formation exposed to hydrogen peroxide stress

Presence of Cronobacter malonaticus in powdered infant formula (PIF) poses a high risk to infant and public health. Cronobacter malonaticus has been widely distributed in food and food processing environments, and the true origin of C. malonaticus in PIF is poorly understood. Control and prevention of C. malonaticus is necessary for achieving microbial safety of PIF. However, little information about decontamination of C. malonaticus is available. In this study, effects of hydrogen peroxide on inactivation and morphological changes of C. malonaticus cells were determined. Furthermore, inhibitory effects of H₂O₂ on biofilm formation in C. malonaticus were also performed. Results indicated that H₂O₂ could completely inactivate C. malonaticus in sterile water with 0.06% H₂O₂ for 25 min, 0.08% H₂O₂ for 15 min, and 0.10% for 10 min, respectively, whereas the survival rates of C. malonaticus in tryptic soy broth medium significantly increased with the same treatment time and concentration of H₂O₂. In addition, morphological changes of C. malonaticus cells, including cell shrinkage, disruption of cells, cell intercession, and leakage of intercellular material in sterile water after H₂O₂ treatment, were more predominant than those in tryptic soy broth. Finally, significant reduction in biofilm formation by H₂O₂ was found using crystal violet staining, scanning electron microscopy, and confocal laser scanning microscopy detection compared with control samples. This is the first report to determine the effects of H₂O₂ on C. malonaticus cells and biofilm formation. The findings provided valuable information for practical application of H₂O₂ for decontamination of C. malonaticus in dairy processing.     

采后BTH处理及粉红单端孢(Trichothecium roseum)挑战接种对厚皮甜瓜果实苯丙烷代谢活性的诱导

以‘玉金香’甜瓜为试材,用0.1g/LBTH浸泡处理10min,测定BTH处理及T.roseum挑战接种对果实苯丙烷代谢关键酶活性和产物积累的影响。结果表明,BTH处理有效降低了损伤接种T.roseum的病斑直径,提高了果实体内苯丙氨酸解氨酶（PAL）、4-香豆酰-辅酶A连接酶（4CL）的活性,增加了总酚、类黄酮及木质素含量。T.roseum挑战接种可进一步促进上述苯丙烷代谢关键酶活性的提高和产物的积累。由此表明,采后BTH处理可通过诱导厚皮甜瓜果实的苯丙烷代谢来增强果实对采后病害的抗性。      

应用亲水作用液相色谱法测定食品中过氧化氢

目的 建立食品中过氧化氢含量的高压液相色谱检测方法。方法 用水提取样品中过氧化氢, 用乙腈做萃取液和流动相, 在1 mL/min流速下, 用Venusil HILIC 色谱柱(250 mm×4.6 mm, 5 μm, 100 ?)不经过衍生化, 直接通过紫外检测器检测食品中的过氧化氢。结果 过氧化氢的检出限为0.6 μg/mL, 定量限为2 μg/mL。对实际样品进行检测时, 平均回收率R≥30%, RSD≤7%。结论 该方法准确、灵敏、精密度高, 可用于食品中过氧化氢的测定。     

红熟期番茄果实根霉果腐病与相关酶活性变化的研究

以"中蔬4号"红熟期番茄果实为材料,采用损伤接种的方法对番茄果实进行处理,测定其苯丙氨酸解胺酶(PAL)和几丁质酶(CHT)活性,研究这2种酶与番茄对根霉果腐病抗性的关系。结果表明,果腐根霉的侵染能够显著提高红熟期番茄果实PAL和CHT的活性,呈现出各自不同的变化趋势。     

Effects of nitric oxide on the alleviation of postharvest disease induced by Penicillium italicum in navel orange fruits

The present study evaluated the effects of 15 μL L^-1 nitric oxide (NO) on the fruit defence response of ‘Newhall’ navel orange. The decay rate of NO-treated navel orange fruits was significantly lower than that of control fruits during storage at 20 °C storage (P < 0.05). Treatment with NO suppressed the increase in disease incidence and lesion area in orange fruits inoculated with Penicillium italicum (P. italicum); significantly increased the activities of phenolic metabolism-associated enzymes and pathogenesis-related (PR) proteins, including polyphenoloxidase (PPO), phenylalanine ammonia-lyase (PAL), β-1,3-glucanase (GLU) and chitinase (CHT); and enhanced the activities of key enzymes, including 4-coumarate: CoA ligase (4CL), cinnamate-4-hydroxylase (C4H) and chalcone isomerase (CHI) in the phenylpropanoid pathway. The contents of total phenolics, flavonoids and lignin were also higher in NO-treated fruits than in control fruits. The findings suggest that exogenous NO could induce disease resistance against P. italicum in navel orange fruits.     

鸡爪中过氧化氢残留量的影响因素研究和检测方法比较

目的模拟凤爪生产过程,研究不同因素对鸡爪中过氧化氢残留量的影响和不同检测方法结果的比较。方法本文用过氧化氢溶液浸泡鸡爪,控制浸泡液浓度和浸泡时间,采用GB 5009.226-2016中钛盐比色法和碘量法测定鸡爪中过氧化氢的残留量。同时进行加标回收和实际样品检测实验。结果当浸泡液浓度达到1.0×103mg/kg及以上时,只需浸泡20 min即在鸡爪中检出较高过氧化氢残留量。鸡爪中过氧化氢残留量随浸泡液浓度和浸泡时间的增加而增加。碘量法和钛盐比色法的检测结果相一致。回收率为86.0%～91.2%,相对标准偏差均小于3.41%(n=6)。结论 2种方法均能有效检测鸡爪中残留过氧化氢。     

宠物咬胶用漂白牛皮中过氧化氢残留量测定及分解研究

目的探究不同温度、过氧化氢酶浓度、反应时间等对牛皮中过氧化氢分解速率的影响规律,以此指导生产中如何控制狗咬胶中过氧化氢残留量超标的问题。方法以生产宠物狗咬胶的漂白牛皮为原料,通过采用不同温度(30~70℃)的水和不同浓度(3%~5%)的过氧化氢酶溶液进行处理,对处理后的过氧化氢残留量进行测定。结果采用50℃温水浸泡漂白牛皮可以较快地去除其中残留的过氧化氢;或者采用浓度为3%的过氧化氢酶溶液,40~50℃,浸泡30 min左右可以更快地去除过氧化氢。根据处理条件的不同,通过试验拟合出方程可以比较准确地计算去除漂白牛皮样品中残留过氧化氢所需要的大体时间。结论通过热处理或者过氧化氢酶溶液处理,能够有效降低漂白牛皮中残留的过氧化氢含量,使最终产品符合要求。     

Potential use and perspectives of nitric oxide donors in agriculture

Nitric oxide (NO) has emerged in the last 30 years as a key molecule involved in many physiological processes in plants, animals and bacteria. Current research has shown that NO can be delivered via donor molecules. In such cases, the NO release rate is dependent on the chemical structure of the donor itself and on the chemical environment. Despite NO's powerful signaling effect in plants and animals, the application of NO donors in agriculture is currently not implemented and research remains mainly at the experimental level. Technological development in the field of NO donors is rapidly expanding in scope to include controlling seed germination, plant development, ripening and increasing shelf‐life of produce. Potential applications in animal production have also been identified. This concise review focuses on the use of donors that have shown potential biotechnological applications in agriculture. Insights are provided into (i) the role of donors in plant production, (ii) the potential use of donors in animal production and (iii) future approaches to explore the use and applications of donors for the benefit of agriculture. © 2016 Society of Chemical Industry