Quality of Shredded Carrots as Affected by Packaging Film and Storage Temperature

ABSTRACT: Different packaging films and storage temperatures were used to establish a range of equilibrium modified atmospheres for storage of shredded carrots. Quality and storage-life of the packaged shredded carrots were determined using sensory evaluation, microbial counts, and a range of physical tests. Minimal processing steps such as peeling and shredding caused physical damage, physiological stress, and enhanced microbial growth, leading to a reduced shelf life when compared to the whole vegetable. A P-plus microporous film (CO₂ permeability of 29 X 10³mL.m ^-2.d ^-1.atm ^-1) was the most suitable for the storage of shredded carrots. Findings indicated that deterioration in these products was triggered by the depletion of oxygen more than by the rise in carbon dioxide.     

自发气调对采后金针菇生理生化的影响

在(2 ± 1)℃、相对湿度95% 的环境中,通过调节气调袋内氧气体积分数(1%、2%、3%、5%)来贮藏金针菇,定期检测呼吸强度、褐变度(BD)、过氧化物酶(POD)、超氧化物歧化酶(SOD)、丙二醛(MDA)等生理生化指标,研究气调贮藏(modified atmosphere storage,MAS)对金针菇影响。结果表明体积分数3% 低氧处理可以抑制金针菇的呼吸作用,维持较高的POD、SOD 酶活性,抑制MDA 含量的增加,减缓营养成分的损失,有助于延缓衰老,延长贮藏期。     

包装薄膜对鲜切莴笋品质的影响

以普通塑料薄膜保鲜袋作对照,研究不同包装薄膜(0.03mm聚氯乙烯薄膜、0.03mm聚乙烯薄膜、0.03mm微孔薄膜)对鲜切莴笋贮藏期间品质的影响。结果表明:0.03mm厚聚乙烯薄膜包装能有效地控制鲜切莴笋的失重率、褐变度、呼吸强度、Vc损失率,提高鲜切莴笋的感官品质和营养价值。     

Modified atmosphere packaging of filleted rainbow trout

Shelf‐lives of filleted rainbow trout (Oncorhynchus mykiss) packaged in over‐wrap, vacuum and gas mixture conditions and stored at 1 ± 1 °C were compared by measurement of pH, total volatile bases (TVB), hypoxanthine content, lipid oxidation (TBARS value), superficial counts of aerobic psychrotrophic flora and sensory analysis (colour, odour and flavour). The gas mixtures evaluated were 10% O₂ + 50% CO₂ + 40% N₂, 10% O₂ + 50% CO₂ + 40% Ar, 20% O₂ + 50% CO₂ + 30% N₂, 20% O₂ + 50% CO₂ + 30% Ar, 30% O₂ + 50% CO₂ + 20% N₂ and 30% O₂ + 50% CO₂ + 20% Ar. Sensory quality deterioration was delayed and bacterial growth as well as increases in pH, TVB and hypoxanthine levels were reduced by modified atmosphere packaging (MAP). Lipid oxidation was higher in gas packages with 20 and 30% O₂ than in those with 10% O₂. Vacuum‐packed fillets presented the lowest TBARS values. In summary, MAP gave rise to a significant extension of shelf‐life when compared with vacuum and over‐wrap packaging. No significant differences were found between the packages containing either N₂ or Ar. The best evaluated atmosphere consisted of 10% O₂ + 50%CO₂ + 40% N₂/Ar. © 2002 Society of Chemical Industry     

PE/CaCO3功能性保鲜膜研制及其在菠菜保鲜中的应用

以LDPE/LLDPE(80/20)为基材,选择CaCO3为无机填充剂,研制PE/CaCO3功能性保鲜膜.测试该保鲜膜的拉伸强度、撕裂强度、透光率、雾度、热封强度、摩擦性能以及透湿性能.并利用该保鲜膜对菠菜进行保鲜包装,通过测定包装内的O2、CO2含量,菠菜的折光率、失重率,并目测每天菠菜的外观变化,考察该保鲜膜对菠菜保鲜的影响,结果表明Ca-40保鲜膜对菠菜的保鲜效果较好.     

包装与贮藏温度对蚕豆采后品质的影响

为明确适宜于鲜食蚕豆采后贮藏的温度与自发气调包装材料,以无保鲜膜包装的蚕豆为对照,研究了(1.0±0.5)℃下聚乙烯(PE)、聚氯乙烯(PVC)、微孔(W)3种保鲜膜包装和(5±1)℃PE保鲜膜包装对蚕豆硬度、色泽、水分含量等品质指标的影响。结果表明,(1.0±0.5)℃下采用PVC保鲜膜包装的蚕豆品质优于其它处理,蚕豆贮藏28d,仍保持较好品质。     

鲜切生菜联合保鲜技术研究

以感官特征、失重率和营养成分作为评价指标;分别采用控制储存温度、选用不同包装材料以及气调包装技术,研究鲜切生菜的保鲜效果。结果表明:生菜失水率达到3%~5%时,叶绿素含量低于2.2 mg/g,便失去了食用价值;最佳的储存温度为5~10℃;在温度9℃,相对湿度90%下,纳米材料保鲜鲜切生菜储存到第14天时,失重率为1.4%,Vc含量为1.38 mg/100 g;在温度5℃,相对湿度90%下,气调法包装的鲜切生菜储存到第18天时,叶绿素含量为2.1 mg/g,Vc含量为1.5 mg/100 g,分别是对照组的1.4,3.5倍。     

不同包装条件下冷却肉品质变化及腐败菌相研究

为寻找冷却猪肉合理的包装方式,延长货架期,将猪后腿肉分别进行托盘包装、真空包装、高氧气调包装（20%CO₂+80%O₂）和低氧气调包装（65%CO₂+35%O₂）处理,并以无包装组为对照,测定样品在4℃贮藏过程中挥发性盐基氮（TVB-N）值、色差值a*、丙二醛（MDA）值、微生物菌落（菌落总数、假单胞菌菌落数和热杀索丝菌菌落数）和感官评分。结果表明:无包装和托盘包装冷却猪肉货架期不超过4 d,高氧气调包装（20%CO₂+80%O₂）货架期为6 d,真空包装和低氧气调包装（65%CO₂+35%O₂）货架期长达9 d。真空和气调包装均有利于延长冷藏猪肉货架期,但真空包装使肉呈暗红色。气调包装中O₂和CO₂的含量影响肉的品质,高氧气调包装有利于好氧菌假单胞菌和热杀索丝菌的生长繁殖,同时促进脂质氧化,但可以很好维持肉色,低氧气调包装（65%CO₂+35%O₂）可以抑制细菌的生长和脂肪氧化。综合各项评判结果,得到最佳包装方式为低氧包装（65%CO₂+35%O₂）。      

Extension of Postharvest Life of Oyster Mushroom by Modified Atmosphere Packaging Technique

ABSTRACT: Mushrooms were packaged in polypropylene, low-density polyethylene, linear low-density polyethylene (LLDPE) packages after washing with 0.5% calcium chloride and 0.5% citric acid (CA), and based on off-color and off-odor development, suitable packaging material and washing solution were selected. Effectiveness of magnesium oxide in modifying the in-package gaseous atmosphere and thereby extending the postharvest life was tested by monitoring the physicochemical properties. Oxygen concentration was 5.5% and 9.9% and carbon dioxide concentration was 8.1% and 4.5%, in the control and packages containing 3 g of magnesium oxide, respectively, on day 12 in storage. Packaging mushroom in 0.015 mm LLDPE packages with 3g of magnesium oxide after washing with 0.5% calcium chloride and 0.5% CA was successful in extending the postharvest life at 8°C and 70% RH from 6 d in commercial samples to 12 d.     

PE/CaCO3保鲜膜研制及其在小白菜保鲜中的应用

以LDPE/LLDPE(80/20)为基材,选择CaCO3为无机填充剂,研制PE/CaCO3功能性保鲜膜.测试该保鲜膜的拉伸强度、撕裂强度、透光率、雾度、热封强度以及摩擦性能.并利用该保鲜膜对小白菜进行保鲜包装,测定O2、CO2含量,小白菜的折光率、失重率,并目测每天小白菜的外观变化,考察该保鲜膜对小白菜保鲜的影响,结果表明Ca-40保鲜膜对小白菜的保鲜效果较好.     

Fresh Mushroom Quality as Affected by Modified Atmosphere Packaging

The effect of O₂ concentration, at 2–6% CO₂ on shelf-life of fresh mushrooms in modified atmosphere packages (MAP) was studied. For conventional mushrooms optimum in-package O₂ was 6% to reduce cap development. Mushrooms irrigated with 0.3% calcium chloride during cropping had a higher rate of maturation and optimum O₂ was 2% during storage. At this low O₂ concentration, however, storage may be potentially hazardous and is not recommended. Surface moisture of mushrooms significantly increased during storage and may have obscured any beneficial effect of MAP on mushroom color. Precise control of relative humidity in the package is recommended.     

脂肪含量和包装方式对法兰克福香肠贮藏品质的影响

以法兰克福香肠为研究对象,以脂质氧化、色泽、质构和挥发性产物为评价指标,研究不同脂肪含量和包装方式对产品贮藏品质的影响。结果表明:随着贮藏时间延长,法兰克福香肠的硫代巴比妥酸值(TBARS)值和亮度均与脂肪含量呈正相关,与包装方式无关;香肠的红度与脂肪含量相关性不显著,与包装方式呈正相关;香肠的硬度和黏性与脂肪含量呈负相关,与包装方式相关性甚小;脂肪含量和包装方式与挥发性产物之间的相关性都较显著。选择较低脂肪含量和真空包装方式有利于保持法兰克福香肠的贮藏品质。     

The effect of packaging treatment on the storage quality of minimally processed bunched onions

Storage quality of minimally processed (MP) bunched onions, as affected by plastic film packaging, was investigated to determine the optimum packing method for this vegetable product. Five different packaging treatments, including two passive modified atmosphere packaging (MAP), two active MAP and a moderate vacuum packaging (MVP), were used for MP bunched onions. Quality attributes of the samples were evaluated periodically in terms of weight loss, colour, decay ratio, microbial counts and sensory properties during storage at 10 °C for 28 days. Various sealed‐packaging treatments did not significantly influence changes in colour of white stem and green leaf tissues, flesh weight loss and microbiological populations including mesophiles, psychrotrophs and lactic acid bacteria. However, sensory attributes and disease incidence were affected by packaging type. MVP with a gas‐permeable plastic film retained better quality bunched onions, with reduced microbial decay and visual sensory aspects, as compared with the other packages.     

冷藏物流过程中不同气调包装对三文鱼品质的影响

为研究3种不同体积分数CO2（50%CO2+50%N2,60%CO2+40%N2及70%CO2+30%N2）的气调包装对存在温度波动的冷藏物流链中三文鱼品质保持的作用,通过测定冷藏物流过程中三文鱼的感官评分、红度值、p H、菌落总数、TVB-N值及K值的变化情况,分析不同体积分数CO2对三文鱼肉品质的影响。结果表明,不同体积分数CO2的气调包装对冷藏物流中温度变化导致的三文鱼品质下降均有减缓作用,其中气体比例为70%CO2+30%N2的气调包装的效果最好。70%CO2的气调包装能够使三文鱼肉维持较低的TVB-N值,同时能抑制微生物的繁殖,保证三文鱼在贮运末期仍有良好的品质。因此,在冷藏物流链中出现温度波动的情况下,采用气调包装能够有效减缓三文鱼肉品质的下降。      

Quality changes in fresh-cut Fuji apple as affected by ripeness stage, antibrowning agents, and storage atmosphere

ABSTRACT:  The effect of ripening state, modified atmosphere, and the use of antibrowning agents was investigated in an attempt to determine optimum ripeness and processing conditions for extending the shelf-life of fresh-cut Fuji apple. Apples were classified in 3 groups: mature-green, partially ripe, and ripe; after peeling and slicing, fruits were treated with 1% (w/v) N -acetylcysteine, or 1% (w/v) ascorbic acid (control), and then packed into polypropylene trays with air or a gas mixture (2.5% O₂+ 7% CO₂+ 90.5% N₂) and sealed. Trays containing the apple slices were stored in darkness at 4 °C ± 1 °C and analyzed periodically during 43 d. Changes in atmosphere composition, color, and firmness were examined. Partially ripe apples, based on their lower ethanol production and maintenance of their original color and firmness, were the most suitable to prepare the fresh-cut commodities. A postcutting dip in 1% (w/v) N -acetylcysteine was the most effective treatment to prevent cut surface browning and preserve the initial appearance of Fuji apple slices during more than 1 mo at 4 °C. Low O₂ and elevated CO₂ (2.5% O₂+ 7% CO₂) atmosphere extended the shelf life of apple slices because of a significant inhibition of ethylene production.     

Modified atmosphere packaging technology: A review

Modified atmosphere packaging is becoming increasingly common. It has been claimed that the technique enables significant shelf-life extension but in so doing presents an increased public health risk. This paper reviews the literature relating to the scientific basis of these claims. It demonstrates that shelf-life, sensory quality and safety of packaged products may be optimised only by harmonising a complex relationship between product and process.     

Effect of gas barrier characteristics of films on aflatoxin production by Aspergillus flavus in peanuts packaged under modified atmosphere packaging (MAP) conditions

The effects of the gas barrier characteristics of three films (ASI, ASII and ASIII) and storage temperature on the growth of, and aflatoxin production by, Aspergillus flavus in peanuts packaged in air and under a modified gas atmosphere of CO₂:N₂ (65:35) were investigated. Mold growth was barely visible in air packaged peanuts using high-medium barrier films (ASI and ASII) and stored at 20°C with more extensive growth occurring in air packaged peanuts stored at 25 and 30°C. Extensive mycelial growth and sporulation occurred in all air packaged peanuts in a low barrier film (ASIII), especially at 30°C. Gas packaging inhibited mold growth in peanuts packaged in a high gas barrier film at 20°C. However, mold growth occurred in gas packaged peanuts packaged in film ASII at higher storage temperatures while extensive mycelial growth was observed in all peanuts packaged in film ASIII irrespective of storage temperature. Levels of aflatoxin greater than the regulatory limit of 20 ng/g were detected in all air packaged peanuts with the highest level of aflatoxin (76 ng/g) being detected in peanuts packaged in a high gas barrier film ASI. Aflatoxin production was inhibited in gas packaged peanuts using a high barrier film. However, higher levels of aflatoxin were detected in all gas packaged peanuts in medium-low gas barrier films (ASII and ASIII), particularly at higher storage temperatures. This study has shown that MAP using a CO₂:N₂ (65:35) gas mixture was effective in controlling aflatoxin production by A. flavus in peanuts to levels less than the regulatory limit of 20 ng/g. However, the antimycotic effect of low O₂-high CO₂ atmospheres is dependent on the gas barrier characteristics of the packaging films, especially at higher storage temperatures.     

包装方式对四角蛤蜊卤制风味产品贮藏品质的影响

目的：研究不同包装方式对其贮藏期品质的影响。方法 对四角蛤蜊卤制风味产品进行普通包装、真空包装、30% CO2+70% N2、50% CO2+50% N2、30% N2+70% CO2气调包装,并在4 ℃贮藏条件下,测定菌落总数、质构特性、色差、TVB-N值、风味特性等理化指标,选择最佳的包装方式。结果 普通包装样品在第3 d、真空包装组样品在第6 d时菌落总数超标,而气调包装组的货架期可达12 d左右。气调包装组的硬度、弹性、咀嚼性的下降程度都低于普通包装和真空包装组,气调包装的护色效果也优于其他两组。气调包装对TVB-N值、TBA值、pH值变化的延缓作用明显优于真空包装和普通包装。结论 不同包装方式对四角蛤蜊卤制风味产品贮藏品质的保持能力依次为气调包装、真空包装、普通包装,其中50% CO2+50% N2气调包装保鲜效果最佳,能显著延长产品货架期。     

冷链物流中包装方式对金枪鱼品质的影响

为研究空气、气调和真空3种不同包装方式对存在温度变化的冷链物流过程中金枪鱼品质的影响,本试验以大目金枪鱼为研究对象,通过测定冷链物流贮藏(-55℃)、运输(-18℃)、销售(2℃)以及消费者家用冰箱贮藏(4℃)等过程中感官指标、菌落总数以及理化指标的变化情况,分析空气、气调(60%CO2,15%O2,25%N2)和真空包装对金枪鱼肉品质的影响。结果表明,气调和真空包装对冷链物流中温度变化导致的金枪鱼品质的劣化均具有缓冲作用,其中气调包装的效果较好。气调包装能使鱼肉保持良好肉色、维持较低的TVB-N值,同时抑制微生物的繁殖和组胺生成,保证金枪鱼肉在贮藏末期仍处于可生食的安全范围。因此,在我国超低温冷链物流尚不完善的情况下,采用气调包装能够有效减缓鱼肉品质下降。