鲜切蔬菜加工保鲜与冷藏链

鲜切蔬菜以其新鲜、方便、营养、无公害等特点,近年来的消费量增加很快。但鲜切蔬菜所涉及到的产业链较长、技术流程复杂,在研发鲜切蔬菜加工和保鲜问题上,整体的技术难度较大。对鲜切蔬菜的保鲜加工工艺和冷藏链的最新研究进展进行了综述。     

The chip‐processing potential of four potato (Solanum tuberosum L.) cultivars in response to long‐term cold storage and reconditioning

BACKGROUND: The reconditioning potential of four potato cultivars (Diamant, Hermes, Lady Rosetta and Spunta) was evaluated in three years of crop production. After 30, 60, 120 and 150 days of storage at 4.5 °C, cultivars were reconditioned at 16 °C for 0, 15 and 30 days before being evaluated for sprout growth, tuber fresh weight loss (FWL), sucrose content, reducing sugar (RS) content (sum of glucose and fructose contents) and chip fry colour (FCL). RESULTS: Reconditioning induced rapid sprouting and pronounced FWL after 120 days of storage. Storage (30–150 days) was not critical to FCL and RS but affected sucrose levels. All cultivars showed an improvement in FCL and a reduction in RS and sucrose after reconditioning. The increment in FCL improvement and RS and sucrose depletion was greater between days 0 and 15 of reconditioning than between days 15 and 30 of reconditioning. Year contribution was significant to FCL and RS but not to sucrose variance. Acceptable FCL was attained after 15 days of reconditioning of Hermes and after 30 days for Lady Rosetta, while Diamant and Spunta remained substandard. RS levels in response to reconditioning were lowest in Hermes and Lady Rosetta. CONCLUSION: FCL conformed to tuber RS accumulation profiles. Cultivar RS ranking following reconditioning remained unaltered from year to year throughout storage. RS and FCL during the first 30 days of cold storage may be a reliable comparative index of reconditioning potential, as high‐RS‐accumulating and poor‐chipping cultivars exhibit inadequate response to reconditioning. Tuber sucrose appeared of little significance as an index of the reconditioning ability of cultivars. Copyright © 2009 Society of Chemical Industry     

Impact of hot water treatment on sprouting,membrane permeability,sugar content and chip colour of reconditioned potato tubers following long‐term cold storage

BACKGROUND: The efficacy of hot water treatment in facilitating successful reconditioning of processing potato (Solanum tuberosum L.) cultivar Hermes following 6 months cold storage at 4.5 °C was examined. Tubers were subjected to hot water treatments (HWTs) at 52.5, 55.0, 57.5 and 60.0 °C for 0–60, 0–50, 0–40 and 0–20 min, respectively, and then reconditioned for 20 days at 16 °C before evaluated for sprouting, fresh weight loss, membrane permeability, sugar content and processing quality. RESULTS: The study demonstrates that in order to achieve complete inhibition of sprouting during potato reconditioning HWTs must exceed the thermal tolerance threshold of the tubers. Short‐duration HWT was effective in retarding sprout growth and tuber dehydration without significantly affecting storage parenchyma membrane permeability, tuber sugar content or processing quality. On the contrary, prolonged HWT caused extensive heat damage, loss of membrane integrity and induced an increase in tuber sucrose and reducing sugar content resulting in deterioration of chip colour in proportion to treatment duration. CONCLUSION: Although HWT at 52.5–60 °C following long‐term cold storage did not improve the processing quality of potato tubers after 20 days of reconditioning, future work is needed to evaluate the effect of short‐duration HWT on the permissible extent of reconditioning and subsequent processing quality. Copyright © 2008 Society of Chemical Industry     

猪肉冷链加工与物流微生物危害分析与控制

基于微生物危害分析,测试冷却分割猪肉冷链加工与物流过程的微生物数量和温度分布,明确关键污染环节和物流过程温度波动,建立关键控制点及其控制措施,制定冷却猪肉冷链加工与物流HACCP计划,提出重点改善卫生管理和温度监控措施,使产品微生物数量控制在可接受水平,确保加工流通过程产品质量安全。     

我国食品冷藏链的现状与发展对策

介绍了国内外食品冷藏链发展概况,分析了我国食品冷藏链的现状及存在的问题,提出了发展我国食品冷藏链的对策与建议。     

Assessment of changes in hop resins and polyphenols during long‐term storage

Changes in the content and composition of hop secondary metabolites during storage are reflected in beer quality and in the economics of beer production. A 12‐month storage experiment with T90 pellets of four hop varieties showed different dynamics of hop aging in relation to both storage conditions and hop variety. Negligible effects on the α‐ and β‐acids were detected during storage without air access at +2°C. Storage at +20°C resulted in a final loss of 20–25% α‐acids, but the content of β‐acids did not change significantly. Large decreases in α‐acids (64–88%) and in β‐acids (51–83%) were found in hops stored with access to air at +20°C. The rate of decline accelerated markedly after 6 months of storage. In terms of hop resin changes, Premiant and Sládek were the most and the least stable varieties, respectively. After 12 months, the content of the total polyphenols and flavonoids decreased by 30–40% and by 20–30%, respectively, irrespective of storage conditions. The rate of decline accelerated strongly after 6 months. The DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) antiradical potential decrease was significant only in hops stored under aerobic conditions. The depletion was 9–25% after 1 year; Saaz was the most stable variety. Copyright © 2012 The Institute of Brewing & Distilling     

Transgenes monitoring in an industrial soybean processing chain by DNA-based conventional approaches and biosensors

The development of analytical methods for genetically modified organisms (GMO) screening is of great interest. In particular, since even highly processed GMO-derived food products are covered by new European legislations, a great effort has been devoted to the application of the analytical tests to these products.     

中国易腐食品冷链物流现状分析及优化研究

中国是易腐食品生产大国、加工大国和消费大国,发展食品冷链物流具有重大的战略意义。文章从界定食品冷链物流概念的基础出发,分析其构成、条件、特点,指出目前存在的问题,并在此基础上提出了优化措施。      

浅谈我国冷藏链物流的主要问题及措施

冷藏链物流现已成为物流发展的重点之一。从冷藏链物流的概念、冷链产品保持质量3T原则、冷藏链物流存在的问题及解决措施等方面阐述了我国冷藏链物流的状况。     

后疫情时代基于区块链技术的食品冷链物流追溯体系构建

以后疫情时代为背景,对中国冷链物流市场发展现状以及食品冷链物流信息追溯体系痛点进行了分析,发现和总结出目前中国食品冷链物流追溯体系存在的问题。并基于区块链技术对食品冷链物流追溯体系进行构建研究,从参与方设置、体系框架设计和运作过程优化3个维度构建了基于区块链技术的食品冷链物流追溯体系,并从政府、企业和消费者3个方面阐述了新构建的追溯体系的具体实现路径。     

Construction of cold‐triggered/heat‐destroyed emulsions for use as a practical cold‐storage thermal history indicator

BACKGROUND: To provide a record of the occurrence of a high‐temperature event during a cold‐chain system in the range from 1 to 10 °C, an indicator material that undergoes an irreversible temperature‐related visual change in response to high temperatures is needed. RESULTS: In order to obtain the required indicator, we attempted to construct highly thermo‐sensitive cold‐triggering and heat‐destructive emulsions that could start monitoring a high‐temperature event just by cooling, and after triggering provide an irreversible visual change over the upper limitation of the monitoring temperature. Emulsions composed of oil mixtures of triacylglycerols and fatty acid esters provided a 1 °C triggering and 10 °C destructive emulsion. The effect of the oil‐phase composition was studied by differential scanning calorimetry, nuclear magnetic resonance and microscopy with a cooling/heating system. CONCLUSION: The emulsion was triggered by cooling at 1 °C and was immediately destroyed by heating to 10 °C, with clear visible phase separation. For cold‐triggering, crystalline structures of frozen oils should work to destroy the interfaces of the emulsion droplets. This could be used as a thermal indicator that would trigger in cold‐chain distribution systems and be destroyed in these systems. Copyright © 2009 Society of Chemical Industry     

典型冷链温度下南美白对虾品质劣变规律及 相关性分析

目的探究典型冷链贮藏温度下南美白对虾品质劣变规律及相关性。方法采用感官评价、仪器分析和理化分析的方法对南美白对虾在-23、0、5℃贮藏温度下的感官、色差、挥发性盐基总氮(total volatile basic nitrogen,TVB-N)含量进行分析与检测,并采用Pearson线性回归分析三者之间的相关性。结果 3种典型冷链贮藏温度下南美白对虾的感官品质变化差异显著,-23℃条件下感官评分一直处于8.0左右;0℃下感官评分在前3 d基本维持在7.0以上,之后快速下降,至第5 d时下降至4.0以下,失去商品价值;5℃条件仅在第1 d维持在7.0以上,第2 d时开始迅速下降。亮度值自贮藏第2 d起不同冷链温度下都有显著性差异(P0.05)。TVB-N值在-23℃条件下第9 d仍在20 mg/100 g以下,而0℃第3 d即发生显著升高(P0.05)。Pearson相关系数表明,TVB-N值与感官评分及亮度变化存在显著相关性。结论与理化检验法相比,感官评价结合色差测定的方法可准确、快速反映对虾鲜度,预测产品货架期。     

Changes in chemical quality indices during long‐term storage of palm‐olein oil under heated storage and transport‐type conditions

Six quality indices, namely free fatty acids (FFA), peroxide value (PV), anisidine value (AV), oxidative stability index (OSI), total tocopherols and headspace volatiles (hexanal, t‐2‐hexenal and t,t‐2,4‐decadienal), were evaluated in a long‐term storage trial of 52 weeks at 50 °C of palm‐olein, a monounsaturated oil. Three concentrations of copper (0.035, 0.17 and 0.69 mg kg^?1) were added. FFA values for all the sample treatments increased slightly over the storage period but remained within acceptable limits. PV of the copper‐containing samples declined initially and then remained stable up to week 40, after which it increased slightly for the 0.035 and 0.17 mg kg^?1 samples. However, PV of the control (no added copper) increased steadily to above the acceptable limit. AV of the copper‐containing samples increased much more than that of the control. OSI and total tocopherol values of the copper‐containing samples were markedly lower than those of the control. t‐2‐Hexenal did not increase during the storage period, whereas hexanal increased in the copper‐containing samples but at a slower rate than in the control. Conversely, the copper‐containing samples had high levels of t,t‐2,4‐decadienal but the control had none. AV, OSI and total tocopherols are the most valuable quality indices for assessing monounsaturated oil quality, whereas FFA, PV and headspace volatiles can be misleading. Copyright © 2003 Society of Chemical Industry     

Production of a high‐protein meal and fermentable sugars from defatted soybean meal,a co‐product of the soybean oil industry

The goal of this research was to produce a high‐protein meal by treating defatted soybean meal, a by‐product of soybean oil production, with dilute acid. Treatments were a mild hydrolysis at 80 °C with sulphuric acid at concentrations ranging from 0.5% to 2.0% (w/v) and times varying from 1 to 16 h that were arranged according to a central composite rotatable experimental design. The end products were an enhanced‐protein meal and a carbohydrate concentrate of fermentable and nonfermentable sugars. The highest protein content rise, from 48% to 58%, was for treatments with concentrations of acid ranging between 1.2% and 1.7% and times between 1.0 and 2.6 h. The maximum yield of fermentable sugar was 21.0% d.b. at 2.0% H₂SO₄ and treatments of at least 6 h. The conditions that provide a highest protein and sugar contents were the treatments with concentrations of sulphuric acid ranging from 0.9 to 1.9% H₂SO₄ for 1–4 h.     

贵阳市农产品冷链物流现状及发展研究

分析了贵阳市农产品冷链物流的现状和主要问题,对贵阳市农产品冷链物流的需求总量进行了预测,并在此基础上提出了促进贵阳市农产品冷链物流发展的对策建议.     

冷链食品病毒控制及其次生危害研究进展

与常规微生物相比, 病毒能在干燥、冷藏和冷冻等恶劣条件下长期存在并保持传染性, 而冷链食品具有全程低温及长途运输的特点, 这使得冷链食品成为全球范围内病毒大面积传播的风险点, 因此, 对冷链食品进行全面消毒也成为控制病毒传播的重要环节。本文围绕冷链食品生产-加工-运输的全链条, 对当前报道的冷链食品病毒传播情况进行了总结, 重点介绍了在低温条件下用于病毒控制的常用化学方法和紫外线照射、电离辐照及低温等离子体等物理方法, 分析阐述了其消毒作用机制、消毒效果及消毒过程中可能产生的次生危害, 为食品安全防控领域从微生物污染防控向病毒污染防控的转变提供理论依据, 为采取科学合理的消毒方式实现对冷链食品病毒传播的控制提供参考。     

Cold‐triggered/heat‐destroyed emulsions composed of phospholipids and triacylglycerols as thermal history indicators for cold‐chain distribution systems

BACKGROUND: Recently, cold‐chain distribution systems have come to play important roles in worldwide food processing/storage/transportation networks. To ensure the maintenance of the quality and safety of foods, it is necessary to develop thermal history indicators for products involved in cold‐chain distribution systems. To provide a record of the occurrence of a high‐temperature event during a cold‐chain system, a temperature‐related phase change in a material within the indicator is needed to indicate that the high‐temperature event occurred. Preferentially, for safety, the materials of the indicators should be edible and easy to handle. It should be possible to store the indicators at ambient temperature before use, and they should be triggered automatically just by cooling at the start of a cold‐chain system. Furthermore, if the indicator is heated even once during the cold‐chain distribution system, its appearance must be irreversibly altered to provide evidence of the high‐temperature experience. RESULTS: Based on the edible materials composed of lyso‐lecithin (15 g), lecithin (2 g), triacylglycerol (150 g), and water, we successfully constructed a stable emulsion that could be triggered just by cooling to 4 °C or lower for more than 12 h. After triggering, it was immediately destroyed by heating up to 20 °C or higher. Furthermore, the mechanism of cold‐triggering and heat‐destruction has been studied by nuclear magnetic resonance. CONCLUSION: The cold‐triggered/heat‐destroyed emulsion should be applied as a new thermal history indicator that can be automatically triggered just by cooling down and irreversibly change its appearance after a high‐temperature experience in cold‐chain distribution systems. Copyright © 2008 Society of Chemical Industry