Some Physiochemical and Sensory Characteristics of Peach Nectar Stored in Various Packaging Materials Under Ambient Conditions

The effectiveness of pouches, including plastic and aluminum foil laminations, in preserving the physiochemical and sensory characteristics of peach nectar compared to the more traditional packages (can and glass jar) was determined. Three sucrose syrup to peach puree ratios (50:100, 60:100, 70:100) were tested and based on the results obtained from a sensory panel, the final study was performed using a ratio of 60:100. The sensory, color, viscosity, and chemical data showed that pouches made from aluminum foil laminations were as good in retaining the quality of the peach nectar as the jar and the can. Significant correlations were found between several instrumental and sensory parameters used in determining the quality of peach nectar.     

Individual Packaging of Apples for Shelf Life Extension

Red Delicious apples after 2 wk and 4 months of cold storage and after 4 months of CA storage were individually packaged in two heat-shrinkable copolymers. Packaged and control apples were stored at 3°C and 90% RH, 21°C and 30°C and 50% RH, and at 30°C and 50% and 70% RH and the effect of packaging on modification of the microatmosphere inside the fruit and on various chemical and physiological changes were monitored with time. Temperature was the dominant storage factor. At 3°C, packaged and control apples had good eating quality and did not show significant differences (P > 0.05) after 3 months of storage. At 21°C, packaged apples reached a minimum acceptable condition at week 6 of storage which represented a shelf life extension of 3-4 wk over nonpackaged controls. At 30°C, internal quality of packaged apples deteriorated faster than controls. The respiration rate of packaged apples was lower than that of controls.     

Sorbitol Increases Shelf Life of Fresh Mushrooms Stored in Conventional Packages

Trays containing 100g of mushrooms overwrapped with PVC film were held at 12°C. Two 3 mm holes were made on top of the ovetwrap for ventilation and a Tyvek^R pouch containing sorbitol was placed at the bottom of the tray before storage. Surface moisture content of mushrooms decreased in the presence of sorbitol. Mushrooms packaged with 10g sorbitol had a constant surface moisture content and those packaged with 15g sorbitol had the best overall color. Principal component analysis of Vis-NIR spectra revealed that surface moisture content affected the scattering of incident light and mushroom color. Lowering of the in-package relative humidity did not affect the maturation rate of mushrooms, but reduced bacterial growth, suggesting that improvement in color was probably due to reduced bacterial activity.     

借助电子鼻对中式传统奶酪货架期进行预测

使用传统的分析方法和商用电子鼻对市售2种中式传统奶酪的货架期进行了预测。通过pH值、酸度和持水力的变化速率判断产品的质量变化;同时,使用电子鼻对相同贮藏期的样品的顶空气味指纹进行检测。结果表明:采用电子鼻系统中的LDA(线性判别法)能更准确判别出不同储藏时间的奶酪,并且和经典的分析方法预测的货架期基本是一致的。     

常温奶酪加工技术及货架期稳定性研究进展

对不同加工技术如热杀菌、真空干燥、超高压、盐溃、气调包装等在延长奶酪货架期中的应用进行综述,探讨了目前常温奶酪加工技术研究中存在的问题和局限,综述了不同加工技术条件对产品货架期内的微生物含量、理化指标、风味的影响,以期为常温奶酪的研究开发提供依据.     

Shelf Life of Shrimp (Penaeus merguiensis) Stored at Different Temperatures

The sensory, microbiological and biochemical changes were determined in shrimp (Penaeus merguiensis) stored at 0° to 35°C. Mean aerobic plate count of fresh shrimp, initially 5.0 × 10⁵ CFU/g, increased with time and temperature to 6.4 × 10⁹ CFU/g at 35°C after 24 hr. A total of 560 different bacteria were isolated and identified. In addition, the dominant organisms were tested for ability to reduce TMAO, produce indole and hydrolyze protein. The initial bacteria were 30% Gram + organisms but changed to predominantly Grampsychrotrophs at lower temperatures and to mesophiles at higher temperatures. Odor, texture and color qualities decreased; TMA, TVB, pH and Indole increased with time and temperature. Shelf life of shrimp ranged from 7 hr at 35°C to 13 days at 0°C.     

不同贮藏温度条件下鲐鱼货架期预测模型的构建

为了探索海上移动运输船上东海鲐鱼新鲜度随温度变化规律及其动力学特性,将鲐鱼贮藏在0、5、10、15 ℃条件下,测定K值、挥发性盐基氮（total volatile base nitrogen,TVB-N）值与菌落总数（total viable count,TVC）,并进行感官评分,研究其货架期预测模型。结果显示,随贮藏时间的延长,鲐鱼的感官品质指标逐渐下降,K值、TVB-N值和TVC均逐渐上升。实验用Arrhenius方程构建了贮藏温度、贮藏时间与K值、TVB-N值和TVC之间的动力学模型,其中,K值变化的活化能（Ea）及速率常数（k0）分别为30.54 kJ/mol和1.54×104;TVB-N变化的Ea及k0分别为41.21 kJ/mol和4.40×105;TVC变化的Ea及k0分别为46.78 kJ/mol 和2.93×106。建立的动力学模型可以在0～15 ℃范围内对鲐鱼的货架期进行准确预测。     

Comparison of Shelf Life of Eggs Coated with Chitosans Prepared under Various Deproteinization and Demineralization Times

Internal quality of eggs coated with chitosans prepared under various deproteinization (DP at 0, 5, 15 min) and demineralization (DM at 0, 10, 20, 30 min) times was evaluated. Chitosans prepared under DP 0 min/DM 30 min, DP 5 min/DM 30 min, and/or DP 15 min/DM 20 min conditions can be effectively used as an egg‐coating material in preserving the internal quality of eggs compared with chitosan prepared under the DP 15 min/DM 30 min condition. The Haugh unit and yolk index values suggested that the chitosan‐coated eggs can be preserved for at least 2 wk longer than the control noncoated eggs during 5 wk of storage at 25°C.     

Modelling the fate of Listeria Monocytogenes in Beef Meat Stored at Refrigeration Temperatures under Different Packaging Conditions

The objective of this study was to model the fate of L. monocytogenes inoculated in beef at two concentrations (2.5 and 4.0 log CFU/g), packaged under aerobic, vacuum and three modified atmosphere combinations – 70%O₂/20%CO₂/10%N₂, 50%O₂/40%C O₂/10%N₂ and 30%O₂/60%CO₂/10%N₂, and refrigerated at a normal temperature (4°C) and at a mild abuse temperature (9°C). An omnibus model based on the three-parameter Weibull equation proved statistically that L. monocytogenes survives better in vacuum (VP) than in aerobic conditions, although without significant difference in its ability to survive in the temperature range between 4°C and 9°C. Furthermore, regardless of the refrigeration temperature, the presence of CO₂ in package atmosphere exerted a bactericidal effect on L. monocytogenes cells, being approximately 1.5 log of reduction when storage time reached 10 days. Since the pathogen can survive in VP/MAP beef at refrigerated storage, there is a need of maintaining its numbers below 100 CFU/g before packaging by placing efforts on the implementation of control measures during processing.     

Shelf Life of Mature Green Tomatoes Stored in Controlled Atmosphere and High Humidity

Freshly harvested mature green tomatoes were washed, sorted and treated with 125 ppm chlorine water. The treated tomatoes were stored at 85% or 98% RH under controlled atmosphere (CA) storage for periods up to 8 wk. The controlled atmosphere was 2.5% O₂, 5.0% CO₂, and N₂ as the balance gas at 12°C. After storing 40 days, the tomatoes were allowed to ripen in air at 23°C. Samples of tomatoes were tested every 3 days to examine changes in quality as determined by visual observation, weight loss, titratable acidity, pH, color and firmness. Weight loss was reduced significantly by CA storage of tomatoes at 98% RH. Tomatoes remained green up to 40 days of storage and changed in color gradually during consecutive storage in atmospheric conditions. Appearance of the tomatoes was acceptable after ripening.     

乳制品企业：不可觑视的“着装”选择

随着人们生活水平的提高，乳品以其营养丰富且易被人体消化吸收的特点，逐渐成为人们日常生活不可或缺的食品之一。虽然目前中国牛奶的人均年平均消耗量只占世界平均水平的1/10，中国人均奶业占有量超过10千克，总产量1350万吨，但是到2030年，人均奶类占有量将达到25千克，总产量可达到4250万吨，其中液态奶的消费量正以30%的幅度递增，     

Active Packaging of Cardboard to Extend the Shelf Life of Tomatoes

In order to extend the shelf life of fresh tomatoes using biodegradable materials, an active microcorrugated cardboard tray package was tested for use with fresh Cherry tomatoes (Lycopersicon esculentum var. cerasiforme). Active packaging characteristics were achieved by coating the interior surface of the cardboard tray with polylactic acid (PLA; 3% w/v) and, after filling with tomatoes, the tray was wrapped with a low-density polyethylene (LDPE) film of 70 or 20 μm thickness and hermetically heat sealed. Uncoated trays were used as control. The trays of tomatoes were stored at 20?±?0.5 °C and 55?±?2% relative humidity, for 30 days, and the ethylene concentration in the package atmosphere was measured periodically as an indicator of ripeness. The following fruit quality parameters were also studied: weight loss, surface colour, microbial count, firmness, soluble solids and pH. It was demonstrated that the capacity of PLA to adsorb ethylene and water vapour and the thickness of the LDPE film were decisive for controlling the ethylene concentration of the package atmosphere and for preventing condensation of water vapour on the fruit and film. The active packaging configuration and storage conditions used preserved fruit quality for a month, thus extending the useful life of the tomatoes and saving refrigeration costs.     

Packaging of Olive Oil: Quality Issues and Shelf Life Predictions

Olive oil has gained much appreciation among consumers worldwide leading to increased markets as well as greater consumer expectation and thus more challenges for the relevant food sector. By understanding the product, its interactions with the environment, and the protective role of the package, decisions can be made on the barrier properties required of the packaging materials to achieve the desired shelf life. To this end, the shelf life of packaged olive oil under various storage and distribution environments can be predicted by mathematical modeling. This review examines the basic factors affecting the shelf life of olive oil in different packaging systems and describes the main oxidative degradation mechanisms for them. Since an experimental investigation to correlate the basic quality factors and the shelf life of a product is time- and effort-consuming, the use of mathematical modeling for the prediction of packaged olive oil shelf life is also discussed. In the presented works, shelf life predictions were based on the most consumer-related attributes; namely, the evolution of olive oil flavor compounds under various packaging and storage conditions. The validation of the simulations against known experimental results showed a very good correlation, confirming the value of the mathematical approach for a quick and accurate prediction of shelf life of oxidation-sensitive products.     

Packaging of Olive Oil: Quality Issues and Shelf Life Predictions

Olive oil has gained much appreciation among consumers worldwide leading to increased markets as well as greater consumer expectation and thus more challenges for the relevant food sector. By understanding the product, its interactions with the environment, and the protective role of the package, decisions can be made on the barrier properties required of the packaging materials to achieve the desired shelf life. To this end, the shelf life of packaged olive oil under various storage and distribution environments can be predicted by mathematical modeling. This review examines the basic factors affecting the shelf life of olive oil in different packaging systems and describes the main oxidative degradation mechanisms for them. Since an experimental investigation to correlate the basic quality factors and the shelf life of a product is time- and effort-consuming, the use of mathematical modeling for the prediction of packaged olive oil shelf life is also discussed. In the presented works, shelf life predictions were based on the most consumer-related attributes; namely, the evolution of olive oil flavor compounds under various packaging and storage conditions. The validation of the simulations against known experimental results showed a very good correlation, confirming the value of the mathematical approach for a quick and accurate prediction of shelf life of oxidation-sensitive products.     

Comparison of Shelf Life and Quality of Mullet Stored at Zero and Subzero Temperature

The shelf life and quality of mullet (Mugil spp.) caught off the Southeast Atlantic coast were evaluated during storage at subzero temperature (-2°C) either unpackaged or vacuum packed in iolon film. Subzero temperature was maintained by storing fish in either 2% NaCl- or 7% propylene glycol-ice. Shelf life of fish stored in -2°C ice was 10 days, compared to 7 days for the fish stored in 0°C ice. Extension of shelf life was attributed to delayed microbial growth and slow biochemical changes. Structural changes due to ice crystals at subzero temperature storage appeared to be minor compared to those which occurred during freezing at -20°C as revealed by microscopic examination. The minor structural changes along with insignificant biochemical changes resulted in products having acceptable eating quality for 10 days.     

气调包装果蔬贮藏寿命预测

在分析气调包装果蔬生理特性的基础上,提出以干物质的分解量作为果蔬产品质量的控制指标,结合气调包装气体交换机理及包装内气体浓度的变化,建立气调包装果蔬的贮藏寿命预测模型。并对一樱桃果品气调包装进行其贮藏寿命的预测。     

Use of Carbon Monoxide Packaging for Improving the Shelf Life of Pork

ABSTRACT: Effects of carbon monoxide in modified-atmosphere packaging (MAP-CO) for pork were investigated. Eighty pork loins (40 injected, 40 uninjected) were used to evaluate color, microbial growth, rancidity, purge, and sensory quality of pork chops in 4 packaging environments (aerobic-overwrap, vacuum, MAP without CO, and MAP-CO). Treatments were evaluated during 36 d of refrigerated storage. Overall Hunter a values were significantly ( P < 0.001) greater in MAP-CO (11.25) than aerobic (6.93) packages. Sensory color values (100 point scale) were also greater for chops in MAP-CO (85.91) than aerobic (62.47) packages. However, MAP-CO did not reduce purge loss. Results showed that CO significantly improved color stability and sensory panel scores for both injected and noninjected pork chops.