不同预冷温度对甜樱桃果实保鲜效果的影响

目的 探究不同预冷温度对采后甜樱桃果实生理品质的影响,找出最适宜的预冷温度,进而推动甜樱桃产业化发展。方法 本实验分别将采后甜樱桃分别预冷至15、12、9、6、3、0℃后回温至室温,以不进行预冷处理为对照组,比较6种处理方式果实预冷和回温过程中的温度变化,并分别测定回温前后果实的色差、呼吸强度及乙烯释放量、硬度、可溶性固形物(TSS)、风味、感官评价,总酚、类黄酮、花色苷、维生素C(Vc)、可溶性蛋白、丙二醛(MDA)含量以及超氧阴离子产生速率(O₂^-)。结果不同预冷温度均可较好地保持果实外观及风味,能够降低甜樱桃果实呼吸强度与乙烯释放量,抑制果实TSS、MDA含量和O₂^-产生速率的上升,延缓甜樱桃果实硬度的下降,从而保持甜樱桃果实的外观品质,且有利于维持甜樱桃果实中的Vc、可溶性蛋白和花色苷含量,以0℃预冷效果最佳,感官评分最高。结论 预冷能够有效维持甜樱桃果实采后的品质,达到增加甜樱桃果实经济价值的作用。     

Efficacy of thyme oil-alginate-based coating in reducing foodborne pathogens on fresh-cut apples

In this study, the inhibition of an alginate-based edible coating (EC) containing thyme oil (0.05%, 0.35% and 0.65%) was evaluated against Listeria monocytogenes, Salmonella Typhimurium, Staphylococcus aureus and Escherichia coli O157:H7 inoculated onto fresh-cut apples. To investigate the antibacterial mechanism of thyme oil, the constituent compounds of that were analysed by gas chromatography-mass spectrometry (GC-MS), and the cellular damage of pathogens was observed by scanning electron microscopy (SEM). Results showed that alginate-based EC containing thyme oil effectively inhibited the growth of pathogens on fresh-cut apples. GC-MS analysis revealed thymol (47.23%) as the major compounds in thyme oil. SEM showed that the cell membrane of foodborne pathogens was damaged by thyme oil, causing their inactivation. Treatment with alginate-based EC containing 0.05% thyme oil preserved the sensory characteristics of fresh-cut apples. Therefore, using alginate-based EC with thyme oil may represent a potential approach to preserve and enhance the safety of fresh-cut apples.     

乙醇熏蒸处理对中华猕猴桃生理代谢及贮藏品质的影响

本研究以中华猕猴桃为实验材料,采用四种浓度0、250、500、1000 μL/L乙醇熏蒸处理,置于0℃贮藏,分别在第0、14、28、42、56、70 d测定其果实硬度、维生素C含量、叶绿素含量、过氧化氢酶(CAT)、多酚氧化酶(PPO)、过氧化物酶(POD)、总酚及类黄酮含量。结果表明:经过乙醇熏蒸处理,呼吸强度明显受到抑制,保持了果实的硬度、减缓了维生素C含量、叶绿素含量的下降速率及褐变发生情况,提高了CAT的活性,保护PPO活性,但对POD影响不显著,同时也提高了总酚、类黄酮等抗氧化物质的含量,达到了保鲜效果,有效延长了中华猕猴桃的货架期。500 μL/L乙醇熏蒸处理能够较好地保护果实的品质,降低酶活性,提高抗氧化物质含量,减缓果实衰老。     

纳他霉素处理对鲜切双孢菇褐变的抑制机理

为研究纳他霉素对鲜切双孢菇褐变的抑制机理,本实验分别采用去离子水（对照）、0.1?g/kg纳他霉素和复合试剂（0.1?g/kg纳他霉素＋10?g/kg?D-异抗坏血酸钠）浸泡处理鲜切双孢菇5?min,并于4?℃下贮藏,分析贮藏过程中多酚氧化酶（polyphenol oxidase,PPO）、酪氨酸酶（tyrosinase,TYR）活力和自由基清除率等多项生理指标。结果表明：纳他霉素和复合试剂处理均能抑制鲜切双孢菇贮藏过程中硬度下降及质量损失率、呼吸强度和相对电导率的上升,降低霉菌和酵母总数,延缓PPO和TYR活力的上升,维持双孢菇子实体VC、还原性谷胱甘肽、总酚和羟脯氨酸含量及谷胱甘肽还原酶和苯丙氨酸解氨酶的活力,有利于双孢菇保持较高的抗氧化酶活力、自由基清除率和总抗氧化能力,从而减轻双孢菇的褐变程度,延长其货架期,其中复合试剂处理的效果更佳。     

Recent advances in shelf life prediction models for monitoring food quality

Each year, 1.3 billion tons of food is lost due to spoilage or loss in the supply chain, accounting for approximately one third of global food production. This requires a manufacturer to provide accurate information on the shelf life of the food in each stage. Various models for monitoring food quality have been developed and applied to predict food shelf life. This review classified shelf life models and detailed the application background and characteristics of commonly used models to better understand the different uses and aspects of the commonly used models. In particular, the structural framework, application mechanisms, and numerical relationships of commonly used models were elaborated. In addition, the study focused on the application of commonly used models in the food field. Besides predicting the freshness index and remaining shelf life of food, the study addressed aspects such as food classification (maturity and damage) and content prediction. Finally, further promotion of shelf life models in the food field, use of multivariate analysis methods, and development of new models were foreseen. More reliable transportation, processing, and packaging methods could be screened out based on real-time food quality monitoring.     

紫外线杀菌技术在鲜切果蔬保鲜中的应用研究进展

目的 通过介绍紫外线杀菌技术在鲜切果蔬保鲜中的应用研究进展,以期为其在鲜切果蔬保鲜中的进一步研究与应用提供参考.方法 综述国内外长波紫外线、中波紫外线和短波紫外线对鲜切果蔬品质、生理代谢相关酶活性以及微生物的影响.结果 紫外线杀菌技术作为一种绿色安全的鲜切果蔬保鲜技术,可以有效抑制鲜切果蔬中微生物的生长繁殖,减缓鲜切果蔬生理代谢,防止褐变,延迟衰老,并延长鲜切果蔬货架期,且不会对鲜切果蔬的风味和口感产生影响.结论 在目前重视食品快捷和安全的趋势下,紫外线杀菌技术因其具有安全方便、对环境友好等特点,现已在鲜切果蔬保鲜中得到广泛应用,并具有重要的发展前景.     

Isolation and identification of procyanidins in apple pomace

The chemical nature of the procyanidin components in apple pomace was investigated as part of a programme seeking alternative uses of the large quantity of pomace that is being generated from the apple juice industry. The homogeneous nature of the procyanidin fractions was demonstrated by the isolation and identification of a range of epicatechin oligomers, namely epicatechin-(4β-6) epicatechin, epicatechin (4β-8) epicatechin, epicatechin (4β-8) epicatechin (4β-8) epicatechin and epicatechin (4β-8) epicatechin (4β-8) epicatechin (4β-8)-epicatechin. The procyanidin polymers were also isolated and purified by a Sephadex LH20 column and shown to consist exclusively of epicatechin units. The chemical structures of these procyanidins were established by ¹³C-NMR spectroscopy, by acid-catalysed degradation reaction with phloroglucinol and by electrospray mass spectrometry.     

食品许可制度对食品安全的保障作用

《中华人民共和国食品安全法》经2015年4月24日第十二届全国人大常委会第十四次会议审议通过,2018年最新修订。食品许可制度作为其组成部分,在保障食品安全方面发挥着重要作用,也是促进食品市场快速稳定发展的有效手段。《中华人民共和国食品安全法》的基本原则是预防为主、风险监管、全程控制、社会共治,而食品许可制度的完善和实施则是建立科学、严格的监管制度的有效举措。本研究从食品许可的种类、对许可证的审查、管理及查验、对许可证的相关处罚等3方面详细解读和分析食品许可制度及其在保障食品安全中所发挥作用,并根据近几年食品市场发展情况对食品许可制度可能存在的问题进行分析,以期为未来食品许可制度的完善提供参考。