Modified atmosphere packaging of fresh produce using microporous earthenware material

Microporous earthenware sheets of 5.5–5.6mm thickness were fabricated with or without a glazing treatment by passing through a sequential firing procedure in a furnace. Their microstructure and gas permeability against oxygen and carbon dioxide were measured and examined for their usability in modified atmosphere packaging of fresh produce. Compared with plastic packaging materials, earthenware sheets with a high proportion of micropores had very high gas permeability and gave CO₂:O₂ permeability ratios close to 1. Glazing treatment smoothed the surface by clogging the pores on the surface and significantly decreased gas permeability, without affecting the internal microstructure of the earthenware. When the earthenware sheet was combined with a plastic box and used in packaging for strawberries and enoki mushrooms at 5°C, its unique permeability properties developed a modified atmosphere that was beneficial for preserving the quality of the produce. Changes in the earthenware's permeability characteristics due to moisture adsorption and condensation need to be resolved so that the dynamic changes occurring in package atmosphere over time can be better understood. Copyright © 2006 John Wiley & Sons, Ltd.     

大米真空保鲜包装技术及动力学模型实验研究

大米保鲜包装技术的关键是如何控制和调节包装内氧气和二氧化碳的体积分数,包装材料气透率是影响包装内气体体积分数的主要因素。综合大米呼吸和薄膜透气2个相互交叉的动态过程,提出了一种新的大米包装薄膜透气率的计算方法。在大米真空保鲜包装试验中,测试了不同真空度以及不同保鲜时间下大米的含水量、脂肪酸含量、还原糖含量、黏度等指标。结果表明,大米的保鲜期至少在180 d以上。     

基于多孔聚氨酯-聚丙烯酸/丙烯酰胺智能材料的恒湿包装设计

以自制多孔聚氨酯-聚丙烯酸/丙烯酰胺(PU-PAA/AM)智能恒湿材料为基础,设计了一种具有防震缓冲和恒湿性能的包装材料,根据其吸湿量与吸湿时间、平衡含湿量与相对湿度的关系,提出了通过控制预吸湿时间来实现存储包装内环境湿度恒定的方法和公式。将防震缓冲和恒湿性能有机结合起来,在武器装备贮运包装领域具有很大的应用价值。     

菠菜微孔膜气调保鲜包装的试验研究

微孔膜气调包装技术是一种有效控制与调节包装内部气氛的方法.采用微孔膜气调保鲜技术包装菠菜,测量菠菜在贮藏过程中包装盒内的O2含量、外观、失重率、色差及叶绿素含量的变化,探讨微孔膜气调包装保鲜技术对贮藏菠菜的保鲜效果,并以无微孔密封包装为对照.结果发现,微孔膜气调包装能更好的维持菠菜的形态与品质.     

军品包装常用的湿度显示方法

介绍了湿度常用表示方法和军品包装上常用的3种湿度显示方法,着重介绍了湿度显示卡在军品包装上的应用及其变色原理,简要分析了湿度显示卡在应用上的一些优缺点。通过对军品包装湿度控制的分析,以及其他2种湿度显示方法的工作原理和优缺点,提出了在军品包装上选用湿度显示方法时,应考虑因素的顺序。     

无菌包装袋的透氧性研究

目的研究无菌包装袋的透氧率与其厚度、材质及温湿度的关系。方法用厚度测试仪测量无菌包装袋厚度,用红外光谱仪检测材质、用氧气渗透测试仪测试透氧率,并比较厚度、材质和温湿度对透氧率的影响。结果无菌包装袋的透氧率随厚度的增加而减小;材质对无菌包装袋的透氧率影响较大;无菌包装袋的透氧率随着温度的增加而增加,阻氧性能下降。结论无菌包装袋的厚度、材质和环境温度对其透氧率均有影响,而相对湿度对透氧率无显著影响。     

不同包装方式对大米保鲜效果影响的研究

高温高湿条件下,不同包装方式对大米品质变化的影响进行分析研究,得出大米品质变化的影响规律.在贮藏初始阶段,环境高温是大米失水的诱因;在贮藏期间,包装材料的透湿性使包装内相对湿度上升,大米吸水.通过测定霉菌数量、分析包装袋内挥发性气体成分及浓度、测定大米光透差等,得出竹炭以其优越的吸附气体特性可以有效地调节包装袋内环境相对湿度和氧气含量等,确保贮藏期间大米的品质.     

Effect of Storage in a Low Oxygen Gas Atmosphere on Colour and Sensory Properties of Pork Loins

The objective of this study was to examine the quality characteristics of packaging materials and packaging units, and the viability and acceptability of the colour and sensorial properties of fresh pork meat during storage in low oxygen and high carbon dioxide modified atmosphere packaging up to 16 days at two temperatures (0°C and 4°C), as well as the sensorial properties of cooked meat. Packaging materials had good mechanical and barrier properties and were suitable for packaging in selected atmosphere. The concentration of oxygen during the whole storage period was less than 0.5% at both temperatures. The proportion of red colour (a*) was successfully maintained although the colour was slightly darker (L*) and the sensory value was lower when evaluated at the end of the storage period. Based on the obtained results and discussion, it can be concluded that samples packaged in a modified atmosphere with 40% CO₂ and 60% N₂ can be stored at 0°C for 15 days and at 4°C for 10 days. Samples had a good sensory quality until the 16th day, with the best results achieved on the 7th day. Copyright © 2013 John Wiley & Sons, Ltd.     

Effect of hinokitiol impregnated sheets on shelf life and quality of “KEK‐1” tomatoes during storage

Hinokitiol (β‐thujaplicin, volatile oil extracted from the wood of Hiba arborvitae [Thujopsis dolabrata var. hondae], cypress family) is a natural preservative, antimicrobial, and chelating agent, used to prevent decay and extend the shelf life of fruits and vegetables. In the present study, we used nonwoven rayon sheets impregnated with hinokitiol to conduct packaging studies. Mature green tomatoes var. “KEK‐1” were packaged under three packaging conditions, ie, modified atmosphere packaging (MAP), MAP + hinokitiol (MH), and perforated film package (as control), and their quality attributes were compared during storage. The packaging materials used were low‐density polyethylene (LDPE) film (40 μm) and fresh sheets of nonwoven rayon impregnated with hinokitiol. O₂ in the MAP packaged tomatoes were retained throughout the storage period (3% to 5% O₂). Results showed that MH had slightly improved quality attributes throughout the storage period when compared with MAP alone. Expression levels of LeACS, LeADH, and LeTBG4 genes were higher in 5 and 9 days of control when compared with MAP and MH. “KEK‐1” tomatoes had longer shelf life under MAP and MH packaging and maintained the quality at 15°C. Hence, the effect of the MAP with bioactive packaging treatments could be effective in the future application for the extension of shelf life and quality of fruits and vegetables.     

自然气调包装对采后苹果蒸腾作用的影响

基于自然气调包装技术设计了一种包装箱,通过对比实验,研究了自然气调包装对采后苹果蒸腾作用的影响规律,建立了自然气调包装苹果的蒸腾作用模型和参数。实验结果和数值分析表明,采用瓦楞纸箱和聚酯镀铝薄膜的自然气调包装技术,可使得采后苹果的蒸腾速率逐渐减小,最后趋于平衡,而且当自然气调包装内环境的相对湿度大于90%时,采后苹果的蒸腾作用可得到较大程度的抑制。     

Development of an Active Thermoplastic Film with Oxygen Scavengers Made of Activated Carbon and Sodium Erythorbate

An active thermoplastic film made of low‐density polyethylene (LDPE) filled with oxygen scavengers made of powdered activated carbon (PAC) impregnated with sodium erythorbate (SE) was developed for packaging applications. Initial tests indicated that the impregnation of PAC with SE enhanced the heat resistance of SE, thereby allowing processing at temperatures typical of LDPE manufacturing. Subsequently, LDPE films with PAC/SE particles were manufactured in coupons that represented a typical juice package, and experiments indicated that these films absorbed 3.57 mg of oxygen in 11 days. This amount corresponded to 80% the concentration of oxygen in the headspace of the package. Furthermore, findings indicated that active particles alone have 10 times higher oxygen absorption capacity than the active LDPE film. Finally, the physical properties of the film were characterized by microscopy where oxygen scavengers showed a good dispersion within the matrix. However, 20 wt.% of these active particles decreased tensile strength of the film by 53%. Copyright © 2014 John Wiley & Sons, Ltd.     

聚乙烯醇基分子筛涂布聚乙烯膜的制备与表征

目的通过调节包装内的湿度,以达到果蔬生长的适宜湿度环境,从而延缓新鲜果蔬的霉变及腐烂速率,延长其保质期,并降低产品损失率。方法将高吸水性树脂PVA与纳米分子筛均匀混合,配制成具有保湿功能的涂布溶胶,采用涂布法将该溶胶与包装基体材料PE相复合,得到一种具有防霉保鲜功能的新型食品包装薄膜。利用电子万能试验机、透氧测试仪、透湿测试仪等仪器测定该复合薄膜的力学性能、阻隔性和透湿性。结果 PVA纳米分子筛/PE复合薄膜在纳米粉体质量分数为1.0%左右时对薄膜物理性能的影响较低,且具有较高的保湿性能,其透气性系数相比未做涂布处理的基材PE大幅降低,透湿量下降20%。结论该复合薄膜在新鲜果蔬的运输、贮存等方面具有潜在的应用价值。     

Toward New Polymeric Oxygen Scavenging Systems: Formation of Poly(vinyl alcohol) Oxygen Scavenger Film

Active packaging is a term that refers to the use of package to do more than merely protect the food from the outside environment. Amongst active packaging, oxygen scavengers can prevent oxidative damage to flavour and colour in a wide range of foods. They offer advantages in maintaining quality and extending shelf life. We thus present the use of a cobalt(II) complex with the ligand l ‐threonine as a new oxygen scavenger. This complex, in addition to its high reactivity with oxygen after water activation, can be obtained easily in large amounts and does not react with oxygen in solid state. Thus, the incorporation of the Co(II)(l ‐Thr)₂(OH₂)₂ natural complex in organic polar polymer (poly(vinyl alcohol)) by casting process was conducted. The reactivity towards oxygen of the obtained films was evaluated by oxidation kinetics monitoring using ultraviolet–visible spectrophotometry as a function of time and relative humidity. Oxygen consumption of the active film was found equal to the complex alone (2.5 mg of O₂ per gramme of complex) after water activation (90.5% relative humidity). Copyright © 2014 John Wiley & Sons, Ltd.     

The interrelation of changes in oxygen content and product quality in modified atmosphere packages of peanuts

The aim of this work was to examine the effect of changes in oxygen content in different types of packages for snacks (multilayer laminated materials, cans) and analyse the changes in the sensorial and physicochemical characteristics of the stored products. Roasted and salted peanuts produced by one of the well‐known companies, packed in modified atmosphere packages (MAP) were the object of this investigation. The interdependence of the changes in oxygen content and product quality was examined in relation to the storage period and type of package used. From the results it can be said that changes in oxygen content in packages of peanuts produce similar effects irrespective of the packaging material used. The correlation observed during storage of peanuts, between changes in oxygen content in different packaging materials and changes of the separate sensorial and physicochemical parameters of the product, especially of the peroxide value, may be a basis for validity forecasting and determination of the optimum composition of gas mixture. This study indicates that evaluation of the quality of packages integrally related to their content should consider both product examination and the package and gas mixture composition, as there may exist an interdependence between quality features of the product and oxygen content in a package. Copyright © 2001 John Wiley & Sons, Ltd.     

Integral approach for optimizing modified atmosphere packages for elstar apples: A combination of product and packaging constraints

Modified atmosphere packages with Elstar apples in various packaging systems have been investigated. Loss of firmness during shelf-life is used as the quality aspect to judge the performance of the modified atmosphere packages. A system-oriented model is derived that describes the experimentally found concentrations well. In the overall approach the time dependency of the oxygen and carbon-dioxide concentrations are discussed. It is shown that the quality attribute, the softening of apples, can be affected by the choice of packaging material. Hence this approach can be used to optimize modified atmosphere packaging of Elstar apples.     

A multi-item multi-packaging model to minimise cost of lost units,unpacking cost and CO2 emissions

This paper presents two multi-objective models that integrate packaging size and production scheduling problems for a flexible flow shop system. The main objective is to find the packaging size of finished product per item and the production schedule that would minimise cost of lost units, unpacking cost, inventory cost, earliness/tardiness penalties and kilograms of carbon dioxide emitted by resources operation. Since the complexity of the proposed models, a Pareto-based hybrid genetic algorithm (HGA) is also developed. A case study was developed to analyse the performance of both models using different instances. Numerical results indicate that the outperformance of one model over the other depends on the demand and the packaging size.     

Prediction of plastic film thickness based on gas permeability and validation with ‘Kyoho’ table grapes for optimal modified atmosphere packaging

Modified atmosphere packaging (MAP) storage has become a useful technique for extending the shelf life of fruit and vegetables. However, the success of MAP depends on many factors, including types of fresh products, storage conditions, and the characteristics of the packaging films. To achieve the optimal gas composition in the package headspace and improve the postharvest quality of fresh produce, the packaging film with appropriate barrier properties needs to be selected. This study aimed to predict the film thickness by applying produce respiration rate and package film permeability data measured in given product weight and storage conditions. An available film (eg, 25‐μm‐thick low‐density polyethylene) was used to pack fresh produce, and the respiration rate of fresh produce and in‐package O₂ and CO₂ concentrations at steady state were measured. Permeability of the film was calculated based on mass balance, and the thickness of the film could be predicted if the recommended target O₂ and CO₂ concentration was obtained from the literature. To validate the predicted thickness value, an experiment was conducted by packaging fresh table grapes in bags of the predicted thickness. The effect of packaging with different film thicknesses on the quality of the fruit was determined. The results showed good agreement between the predicted and the experimental in‐bag O₂ and CO₂ concentrations, and the MAP with predicted thickness (90 μm) film was more effective in maintaining postharvest quality of grapes during low‐temperature storage than the thinner films (30 and 60 μm) and the control.     

A Multi‐functional Biofilm Used as an Active Insert in Modified Atmosphere Packaging for Fresh Produce

We developed a multi‐functional agar‐based biofilm for fresh produce packaging by modulating its CO₂ absorption and water vapour absorption functions. The film was prepared from solutions containing agar as a matrix and a water vapour absorbent, glycerol as a plasticizer, and sodium carbonate (SC) and/or sodium glycinate (SG) as a CO₂ absorbent. The optical, mechanical, and CO₂ and water vapour absorption properties of SC, SG, and SC/SG films were investigated. Multi‐functional films tended to show poor mechanical properties, with a hard texture and an opaque and yellowish colour. The three films had different CO₂ absorption capacities and coefficients, with SC film showing the highest absorption, followed by SC/SG and SG films. The water absorption coefficients were much higher than those of CO₂, with the opposite dependence on the absorbent compound. The multi‐functional benefits of the developed film were shown by using the film for modified atmosphere packaging (MAP) of shiitake mushrooms as an insert label. A tailored MAP design for shiitake mushrooms was produced based on mass transfer mathematical models. The package attached with SC film label was capable of generating the desired internal atmosphere and thus showed the best quality preservation in terms of colour, firmness, flavour score, and bacterial growth after 5‐day storage. A tailored MAP system with our multi‐functional film can provide an optimal modified atmosphere for CO₂‐sensitive fresh commodities, preserve their quality, and extend their shelf life. Copyright © 2015 John Wiley & Sons, Ltd.     

包装设计流程的活性分析模型研究

在资讯化社会快速发展的背景下,通过使用活性系统分析法及工具分析复杂的商业包装设计流程,尝试构建了通用包装设计流程的概念模型,并提出了如何改良的建议和想法。根据改良后的概念模型,开发出了一套集知识管理信息为一体,具有简易操作界面设计的软件工具。利兹大学设计学院的硕士生们,通过对奶酪乳制品进行包装设计的实践创作对软件进行了测试,测试反馈的结果为完善软件的设计提供了一定的支持和帮助。     

自然气调包装设计探讨

从塑料薄膜的透气性与果蔬的呼吸强度间的关系出发,推导了自然气调包装各设计要素的关系式。应用这些关系式可以对自然气调包装进行合理设计。