静电场结合自发气调包装对马铃薯贮藏期间的保鲜效果

以延长马铃薯的货架期并保持其品质为目的,选用阻隔性材料聚乳酸（polylactic acid,PLLA）薄膜对采后新鲜马铃薯进行自发气调包装,设置无包装的空白组为对照,以低温冷藏为前提（均设置4 ℃、85%相对湿度）,分别置于电场和无电场两组环境贮藏,测定贮藏过程中气体组分、感官评分、质量损失率、a*值、干物质质量分数、可溶性固形物质量分数、淀粉质量分数及VC含量。结果表明：静电场可以显著抑制马铃薯表皮变绿及发芽;PLLA自发气调包装可形成一个相对高CO2体积分数（4.2%～8.0%）和低O2体积分数（7.7%～12.3%）的气体组分;综合了静电场保鲜与自发气调包装的静电场-气调组保鲜效果最佳,该组水分、感官品质保持最好,各项营养成分损失较慢,贮藏150 d仍具有食用价值。因此,静电场和自发气调包装联合处理有利于马铃薯的保鲜贮藏。     

微波热烫和气调包装对中央厨房用胡萝卜理化特性及品质的影响

胡萝卜经去皮、切分等加工后容易受到氧气和微生物的作用而发生腐败变质,因此,需要合适的保鲜方法延缓其品质劣变。作者研究微波热烫和气调包装对鲜切胡萝卜贮藏品质的影响。对胡萝卜进行微波热烫和气调包装处理后,每隔5 d测定胡萝卜样品的硬度、β-胡萝卜素质量分数、水分质量分数、水分活度、水分状态、过氧化物酶活性、颜色和微生物数量等指标。微波热烫可以有效降低胡萝卜中的微生物数量,并降低其水分迁移率。相比之下,对照样品中自由水（T₂₄）的质量分数更为突出。360 W微波热烫300 s结合高氧气调包装（体积分数80% O₂、10% CO₂、10% N₂）降低了储藏期内胡萝卜中β-胡萝卜素的降解、硬度的损失和过氧化物酶的活性,且更好地控制了胡萝卜中水分活度和水分质量分数的增加。低功率微波热烫结合高氧气调包装是一种有效的保鲜方法,可用于改善胡萝卜的储藏品质。     

高体积分数CO2气调包装对冷藏凡纳滨对虾品质的影响

为研究高体积分数CO2气调包装对凡纳滨对虾品质的影响,以空气包装为对照,分别采用100% CO2、80% CO2＋20% N2和50% CO2＋10% O2＋40% N2气调包装对虾,并在（4±1）℃条件下贮藏10 d,期间每2 d测定对虾细菌总数及其挥发性盐基氮值、肌肉纤维长度、硬度、多酚氧化酶活性、白度、感官评分的变化。结果表明：在冷藏条件下,高体积分数CO2气调包装能有效抑制细菌的生长繁殖和多酚氧化酶的活性,且CO2体积分数越高抑制效果越明显;但100% CO2处理的对虾与80% CO2组相比,其样品挥发性盐基氮值较高,肌肉纤维长度和硬度均较小,感官品质较差;50% CO2组对虾白度较低,与空白对照组差异不明显。因此,所选取高体积分数CO2气调包装中,80% CO2组的保鲜效果最佳,能有效延长凡纳滨对虾的冷藏货架期至8 d。     

不同浓度CO2对箱式气调贮藏树莓保鲜效果的影响

以Heritage品种树莓作为试验材料,采用塑料气调保鲜箱,通过分析贮藏过程中箱内O2、CO2气体、果实感官及主要生化指标的变化,研究了不同体积分数CO2对树莓鲜果贮藏保鲜效果的影响。结果表明:CO2处理对箱式气调贮藏树莓的保鲜效果具有一定影响,其中,CO2体积分数为5%的处理,贮藏过程中箱内CO2和O2体积分数变化幅度均较小,果实PPO活性的升高和MDA的积累受到一定的抑制,果实POD活性维持了较高水平,贮藏至40d时果实色泽基本无变化,香气略变淡,仅个别果实表面有零星水珠出现。由此表明,CO2体积分数为5%更适宜树莓箱式气调贮藏,维持果实品质。     

气调贮藏对毛豆采后叶绿素降解的影响

本文研究了5% O₂气调贮藏条件下，不同体积分数CO₂(4% CO₂、8% CO₂、12% CO₂)对毛豆叶绿素降解的影响。结果表明:气调贮藏能够有效延缓毛豆荚的黄化以及叶绿体超微结构分解，保持较好的外观品质；在毛豆贮藏过程中CO₂处理显著抑制了脱植基叶绿素a和脱镁叶绿酸a含量的上升，延缓叶绿素的降解，贮藏第20天时，8% CO₂贮藏组叶绿素a/b含量分别为40.32 μg/g和20.37 μg/g，显著高于对照组；同时CO₂贮藏组显著钝化脱镁螯合酶以及脱镁叶绿素酶的活性，在贮藏末期8% CO₂贮藏组酶活性相比对照组分别降低了19.8%和7.2%。因此，毛豆在5% O₂+8% CO₂气调贮藏条件下效果最佳。     

基于主成分分析验证气调对番茄品质的影响

研究低温环境下不同体积分数的混合气体对番茄感官品质、营养价值的影响。以番茄作为试验研究对象,通过预冷处理,选择开孔率5%的聚乙烯食品包装袋包装,放在温度为8 ℃ CO2体积分数为6%的气调箱内,用N2调节O2体积分数为2%、4%、6%、8%和10%。每隔2 d检测一次番茄品质（质量损失率、色差L*值、TSS、TA及主观评价）之后对6个评价指标进行标准化处理,采用主成分分析法建立得分函数,并用传统感官评价验证得分模型。试验研究表明：4% O2+6% CO2气调环境下番茄各项指标可以维持较好的水平。综合函数评价得分显示在长期气调保鲜过程中,低氧环境有利于番茄保持较高品质。传统感官评价方式与综合函数有一致性。主成分分析法表明4% O2+6% CO2的气调环境下具有较高的得分水平,可以显著维持保鲜过程中番茄的营养价值,并延长气调保鲜周期。     

自发气调包装对芥蓝采后叶绿素降解及品质保持的影响

为了探究不同自发气调包装对芥蓝贮藏期间品质与叶绿素降解的影响,分别用市售低密度聚乙烯(LDPE)微孔保鲜袋和2种改性LDPE气调袋包装贮藏采后芥蓝,定期测定包装袋内气体及品质变化相关指标。结果表明:在15℃贮藏期间,对照袋内O₂与CO₂体积分数无明显变化,而气调袋内O₂在贮藏初期迅速下降,CO₂快速积累。2种改性气调袋包装均减缓了叶片黄化、失重速率,维持了叶片较高的叶绿素、维生素C、可溶性蛋白质量比。贮藏3d 时,2种改性LDPE气调袋包装组商品率为100%,叶绿素质量比分别下降了14.67%、4.74%;而对照组商品率仅为51.25%,叶绿素质量比下降了26.47%。通过测定叶绿素降解酶活性及检测相关基因表达分析发现,芥蓝叶片黄化衰老过程中叶绿素含量的变化受到CLH1、PPH、PAO、RCCR、NYC基因表达量的调节,且CLH1主要在芥蓝叶片初始衰老过程叶绿素的降解中起作用。自发气调袋包装可减缓芥蓝的生理代谢变化,抑制叶绿素降解酶基因表达变化,延缓叶片黄化,研究结果旨在为控制芥蓝采后品质劣变及贮藏保鲜提供理论依据。     

微环境波动对冰温气调贮藏蓝莓品质的影响

为探究冰温气调状态下微环境波动(即温度波动、气体环境波动、温度气调双波动)后蓝莓品质的变化规律,以“蓝丰”蓝莓为试材,预冷处理后分别放入不同的冰温(-2 ℃和-1 ℃)气调(CO₂:10%~14%;O₂:6%~9%)环境贮藏7 d,分析蓝莓果实的最佳贮藏环境状态。在此基础上,设计3组微环境波动试验,即温度波动、气调波动、温度和气调双波动,分别波动1~6 d,每次波动结束后采取相应措施进行贮藏,测定1~7 d各试验组蓝莓果实的硬度、内聚性、可滴定酸含量、花青素含量、丙二醛含量。结果表明,试验组的保鲜效果更好。微环境波动试验中,蓝莓的最佳贮藏时间1 d。“蓝丰”蓝莓果实的最佳冰温气调环境为-1 ℃(CO₂:10%~12%;O₂:6%~9%),蓝莓果实品质与波动时长呈负相关,采用降温/降氧/双降手段虽有一定效果,但不能使蓝莓果实品质恢复至冰温气调组的最佳状态。     

高浓度CO2胁迫对软枣猕猴桃贮藏期间细胞壁代谢的影响

为研究贮藏期间高浓度CO₂胁迫对软枣猕猴桃细胞壁代谢的影响,以“龙成二号”为试验材料,以微环境气调箱为载体,分别粘贴气调元件A(CK2)、气调元件B(TR),以不粘贴气调元件为CK1,研究高浓度CO₂胁迫对冷藏期间果实果皮强度、细胞壁多糖、细胞壁降解酶及活性氧(ROS)的影响。在60 d时分析不同处理组果实果皮微观结构的差异。结果表明:冷藏过程中,CK2组中形成适于软枣猕猴桃贮藏的环境(O₂含量17.00%～20.92%,CO₂含量1.63%～2.78%),而TR组形成高浓度CO₂胁迫的贮藏环境(O₂含量11.22%～15.55%,CO₂含量9.00%～11.93%)。与CK1和CK2相比,TR组可阻碍果皮强度的降低,影响原果胶、纤维素、半纤维素含量的正常下降,抑制水溶性果胶的升高,降低多聚半乳糖醛酸酶(PG)、纤维素酶(CX)、β-半乳糖苷酶(β-Gal)及淀粉酶活性,加快超氧阴离子(O₂·-)活性、过氧化氢(H2O₂)、丙二醛(MDA)含量及相对电导率的上升;同时果皮细胞结构破坏严重,表皮粗糙凌乱,细胞间隙增大,组织轮廓模糊紊乱。分析表明,TR组软枣猕猴桃贮藏期间环境CO₂含量超过耐受阈值,引起果实僵直,硬度下降缓慢,影响后熟进程,细胞壁多糖代谢转化受到抑制,组织内自由基大量积累,膜脂过氧化,细胞结构被破坏,丧失商品性。     

CO2气调处理对鲜莲贮藏品质的影响

为研究CO₂气调处理对鲜莲采后贮藏品质的影响,以“十里荷一号”鲜莲为试材,在4 ℃、5% O₂条件下,分别采用不同CO₂(4%,8%和12%)贮藏鲜莲20 d,测定其外观及营养品质。结果表明:4% CO₂处理虽可降低莲子的失重率和褐变度,但淀粉消耗较为严重,贮藏20 d后淀粉含量(98.01 mg/g)比对照组(104.99 mg/g)低6.98 mg/g;8% CO₂处理在贮藏结束时褐变度、失重率、还原糖含量分别为1.63,8.54%,0.76%,过氧化物酶(POD)和多酚氧化酶(PPO)活性分别为163.44 U/(min·g)和99.63 U/(min·g),均显著低于对照组和其它气调处理组(P<0.05),而淀粉含量为119.68 mg/g,显著高于其它处理组(P<0.05)。12% CO₂处理使莲子受到高浓度CO₂伤害,贮藏20 d后其a*值(-10.03)高于对照组(-12.68),而b*值(24.95)低于对照组(28.03),褐变程度也比对照组更明显。本研究结果表明,5% O₂ + 8% CO₂为较适宜新鲜莲子贮藏保鲜的气调参数。该处理在减少莲子营养物质消耗和表皮护绿等方面也表现出积极作用,研究结果为研发鲜莲采后保鲜技术提供了参考。     

Shelf-life of Domiati cheese under modified atmosphere packaging

The present study describes the effects of modified atmosphere packaging (MAP) on shelf-life extension, chemical, microbiological, and sensory properties of Domiati cheese. Five different MAP were studied [10% CO₂/90% N₂ (G1), 15% CO₂/85% N₂ (G2), 25% CO₂/75% N₂ (G3), 100% CO₂ (G4), and 100% N₂ (G5)]. Control samples were packaged in air (CA) and under vacuum. In both groups of cheeses, chemical analysis was significantly affected by MAP during cold storage. Ripening indexes were significantly affected by MAP during cold storage. Microbiological data showed that G4, followed by G5, were the most effective groups inhibiting the growth of total aerobic mesophilic and psychrotrophic bacteria, and yeasts and molds until the end of storage. Sensory evaluation was significantly affected by MAP and storage period, at 45 d CA cheese samples were judged as unacceptable. The best sensory properties were obtained in G5, G4, and G3 treatments, and recorded a relatively higher sensory evaluation scores. The best shelf-life extension was obtained in G5, G4, and G3 treatments.     

Preservation of precut white cheese by modified atmosphere packaging

Effects of modified atmosphere packaging (MAP) on storage stability and quality of precut fresh and aged white cheese were investigated. Fresh or aged white cheese was cut into small cubes and packaged in five different atmospheres [0% O₂ + 0% CO₂ + 100% N₂ (MAP1), 10% O₂ + 0% CO₂ + 90% N₂ (MAP2), 0% O₂ + 75% CO₂ + 25% N₂ (MAP3), 10% O₂ + 75% CO₂ + 15% N₂ (MAP4) and aerobic (air)]. Control samples were packaged in brine and vacuum for fresh and aged white cheese, respectively. Changes in gas composition, total plate count, lactococci, lactobacilli, yeast and mould counts, proteolysis, lipolysis, pH, colour, texture and sensory properties were investigated during refrigerated storage. The best packaging treatment for the fresh cheese was MAP3, as it inhibited mould growth and protected the hardness. MAP2 can be recommended for the packaging of the aged cheese, as it decreased lipolysis.     

Extending the shelf life of fresh ewe’s cheese by modified atmosphere packaging

This study evaluated the effect of modified atmosphere packaging (MAP) in extending the shelf life of a fresh ewe’s cheese stored at 4 °C for 21 days. Three batches were prepared with 20, 30 or 50% CO₂ with N₂ as filler gas. MAP controlled well the microbial growth, and the best result was obtained with 50% CO₂. Pathogens were not detected in any sample. Softening of cheese was best reduced by 30% or 50% CO₂. The sensory characteristics of the cheeses markedly decreased during storage. Only the sample stored with 50% CO₂ obtained an overall score above the acceptability at 14 days.     

Microbiological,chemical and sensory assessment of mussels (<Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis>) stored under modified atmosphere packaging

Wild mussels (Mytilus galloprovincialis), were packaged aerobically under vaccum packaging(VP) and modified atmosphere packaging (MAP (50%/50% CO₂/N₂: M1, 80%/20% CO₂/N₂: M2, 65%/35% CO₂/N₂: M3), and stored at 2 ± 1 °C. Quality evaluation was carried out using microbiological, chemical and sensory analyses. Microbiological results revealed that M2 and M3 delayed microbial growth compared to M1. Of the chemical indices determined, the TVB-N and TMA-N values of M2 remained lower than the proposed acceptability limits of 35 mg N/100 g and 8 mg N/100 g, respectively, up to 8 days of storage. All of the MAP and VP mussel samples exceeded these limits after 12 days of storage. All samples retained desirable sensory characteristics during the first 8 days of storage. Based on microbiological and chemical analyses along with sensory evaluation, M2 and M3 gave a longer shelf-life compared with VP and M1. M2 gas mixture was the most effective for mussel preservation.     

Nondestructive and Continuous Monitoring of Oxygen Levels in Modified Atmosphere Packaged Ready‐to‐Eat Mixed Salad Products Using Optical Oxygen Sensors,and Its Effects on Sensory and Microbiological Counts during Storage

The objective of this study was to determine the percentage oxygen consumption of fresh, respiring ready‐to‐eat (RTE) mixed leaf salad products (Iceberg salad leaf, Caesar salad leaf, and Italian salad leaf). These were held under different modified atmosphere packaging (MAP) conditions (5% O₂, 5% CO₂, 90% N₂ (MAPC—commercial control), 21% O₂, 5% CO₂, 74% N₂ (MAP 1), 45% O₂, 5% CO₂, 50% N₂ (MAP 2), and 60% O₂, 5% CO₂, 35% N₂ (MAP 3)) and 4 °C for up to 10 d. The quality and shelf‐life stability of all packaged salad products were evaluated using sensory, physiochemical, and microbial assessment. Oxygen levels in all MAP packs were measured on each day of analysis using optical oxygen sensors allowing for nondestructive assessment of packs. Analysis showed that with the exception of control packs, oxygen levels for all MAP treatments decreased by approximately 10% after 7 d of storage. Oxygen levels in control packs were depleted after 7 d of storage. This appears to have had no detrimental effect on either the sensory quality or shelf‐life stability of any of the salad products investigated. Additionally, the presence of higher levels of oxygen in modified atmosphere packs did not significantly improve product quality or shelf‐life stability; however, these additional levels of oxygen were freely available to fresh respiring produce if required. This study shows that the application of optical sensors in MAP packs was successful in nondestructively monitoring oxygen level, or changes in oxygen level, during refrigerated storage of RTE salad products.     

Influence of vacuum or high-oxygen modified atmosphere packaging on quality of beef M. longissimus dorsi steaks after different ageing times

The objective of the study was to determine if beef quality parameters differ between steaks in modified atmosphere packaging (MAP; 80% O₂ and 20% CO₂) and in vacuum packaging. Both M. longissimus dorsi (LD) from ten young bulls were cut in steaks day 3 postmortem and frozen either directly or after storage for 5 or 15 days in MAP and/or vacuum. The parameters studied were Warner Bratzler shear force, colour stability, α-tocopherol content, protein oxidation, water holding capacity and sensory attributes. Steaks stored in MAP had higher shear force than steaks stored in only vacuum at all ageing times. Tenderness and juiciness were negatively affected by storage in MAP. Ageing in MAP induced higher levels of metmyoglobin compared with vacuum ageing. In conclusion, high-oxygen MAP negatively influenced shear force, thawing loss, α-tocopherol content and colour stability, as well as the sensory attributes tenderness, juiciness and to some extent meat flavour.     

Controlled and modified atmospheres influence chilling injury,fruit quality and antioxidative system of Japanese plums (Prunus salicina Lindell)

Our objective was to compare the effects of controlled atmosphere (CA) and modified atmosphere packaging (MAP) on fruit quality, chilling injury (CI) and pro‐ and antioxidative systems in ‘Blackamber’ Japanese plums. Matured fruit were stored for 5 and 8 weeks at 0–1 °C in normal air, CA‐1 (1% O₂ + 3% CO₂), CA‐2 (2.5% O₂ + 3% CO₂) and MAP (~10% O₂ and 3.8% CO₂). CA was more effective than MAP in retention of flesh firmness and titratable acidity during cold storage. Fruit stored in CA‐1 showed reduced CI and membrane lipid peroxidation after 5 and 8 weeks of cold storage. Low O₂ atmospheres appeared to limit the generation of reactive oxygen species (ROS) and their efficient scavenging through the concerted action of superoxide dismutase and peroxidase. The role of ascorbate–glutathione (AsA–GSH) cycle in the regulation of oxidative stress was also studied during and after storage in different atmospheres. In conclusion, optimum CA conditions delayed fruit ripening and CI through augmentation of antioxidative metabolism and suppression of oxidative processes.     

Effects of novel modified atmosphere packaging on lipid quality and stability of sardine (Sardina pilchardus) fillets

Modified atmosphere packaging (MAP) is an efficient method to increase shelf-life of fishery products by inhibiting bacterial growth and oxidative reactions. Beside the traditional gases used for MAP, novel gases such as argon (Ar) and nitrous oxide (N₂O) were approved for food use in the European Union. The present research investigates the effect of MAP with unconventional gas mixtures, that previously positively affected microbial shelf-life, on colour, lipid oxidation and sensorial characteristics of sardine fillets during storage. Four atmosphere conditions were tested: Air (20.8% O₂/79.2% N₂), N₂ (30% CO₂/70% N₂), N₂O (30% CO₂/70% N₂O) and Ar (30% CO₂/70% Ar). Samples were stored for 12 days at 3 °C. Results showed that the removal of oxygen significantly inhibited the oxidation process; however, most of the investigated parameters related to fat oxidation did not show any improvement, except for a slight decrease in lipid hydrolysis and improvement in sensory properties in the packaging containing Ar.     

The impact of packaging system and temperature abuse on the shelf life characteristics of ground beef

New ground beef packaging systems have warranted investigation of their spoilage and quality characteristics. Furthermore, analysis of ground beef spoilage in modified atmosphere packaging (MAP) and stored at abusive temperature is lacking. This research aimed to determine the effect of packaging systems and temperature abuse on the sensory and shelf-life characteristics of ground beef. Ground beef patties were packaged using polyvinyl chloride overwrap (OW), HI-OX MAP (80% O₂, 20% CO₂), LO-OX MAP (30% CO₂, 70% N₂), CO-MAP (0.4% CO, 30% CO₂, 69.6% N₂), or vacuum (VAC) prior to color, odor, biochemical, and microbial analyses over display. CO-MAP exhibited more desirable color and consumer acceptability throughout display. Lean discoloration and odor scores were lower for anaerobic packaging than aerobic packaging. Microbial results mirrored sensory preferences for anaerobic packaging. These results indicate anaerobic packaging extends shelf-life properties and desirable sensory attributes throughout display and temperature abuse.     

Effectiveness of CO2and Nisaplin on increasing shelf-life of fresh pizza

Acidification and CO₂release resulting from fermentative metabolism of lactic acid bacteria and yeasts were the principal grounds for rejection of ham pizza stored under 20% CO₂(commercial conditions). Ham and tomato paste were identified as major sources of fermentation. A rotatable factorial design with the aim of studying the effects of Nisaplin and modified atmosphere packaging (MAP) showed that CO₂reduced gas release and had little effect on acidification. In contrast, Nisaplin did not have a significant positive effect on gas release, although it minimized acidification at high CO₂concentrations. The combined use of Nisaplin and MAP lead to significant increases in shelf-life in relation to commercially stored samples, and were ascribed to complementary effects of nisin and CO₂against lactic acid bacteria and yeasts, respectively. Subsequent studies aiming to optimize the addition of Nisaplin showed that optimum effectiveness in spoilage prevention could be achieved by using highly CO₂-enriched atmospheres in conjunction with 100 mg kg⁻¹of Nisaplin added to the top of the pizza and mixed in the tomato paste.