气调包装对鲜切莲藕保鲜效果研究

为保持鲜切莲藕贮藏品质、延长货架期,研究气调包装对鲜切莲藕的保鲜效果.采用8种不同浓度配比的O2、N2和CO2气体对鲜切莲藕进行包装,置于4℃下贮藏,定期测定鲜切莲藕VC的含量、多酚氧化酶活性、褐变度以及pH值变化.结果表明:鲜切莲藕多酚氧化酶的活性与其褐变度有着密切关系,100%O2组处理的鲜切莲藕,其外观最好,多酚氧化酶活性受到抑制,VC含量比对照组的损失最小,pH值下降幅度比对照组低.     

不同气调包装结合冰温贮藏对羊肉保鲜效果的影响

为延长鲜羊肉的保鲜时间,研究不同气体组分的气调包装对羊肉冰温贮藏过程中品质的影响。以真空包装为对照,比较75% O2＋25% CO2、75% N2＋25% CO2气调包装羊肉在－1 ℃冰温条件下贮藏过程中感官品质、色泽、汁液流失率、嫩度、挥发性盐基氮、pH值、微生物等品质指标的变化。结果表明：真空包装羊肉的汁液流失率显著高于2 种气调包装,而75% N2＋25% CO2气调包装羊肉的色泽和感官评分最差。75% O2＋25% CO2气调包装的保鲜效果最好,其色泽和感官评分最高,汁液流失率较小,pH值最低,－1 ℃冰温条件下贮藏42 d时,羊肉的菌落总数、假单胞菌菌数、乳酸菌菌数的对数值分别为5.91、5.95、5.23 （lg（CFU/g））,其中菌落总数指标符合国家二级鲜肉标准。因此,－1 ℃冰温条件下结合75% O2＋25% CO2气调包装可以使羊肉有效保鲜42 d,是较好的鲜羊肉保鲜方法。     

不同气体组分气调包装对冷鲜鸡肉贮藏品质的影响

以宰杀12 h内的新鲜鸡肉为供试样品,采用5% O2＋40% CO2＋55% N2（处理组1）、10% O2＋40% CO2＋50% N2（处理组2）、40% CO2＋60% N2（处理组3）3 种不同组分气体进行气调包装,以托盘包装为对照组,通过测定鸡肉贮藏过程中包装内的O2含量、CO2含量、样品的挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、红度值（a*）、菌落总数、pH值、硫代巴比妥酸反应物（thiobarbituric acid reactive substance,TBARs）值等指标的变化,分析3 种不同气体组分气调包装对0～4 ℃条件下贮藏14 d鸡肉品质的影响。结果表明：处理组1、3可显著延缓冷鲜鸡肉贮藏过程中pH值、TVB-N含量、菌落总数的增加（P＜0.05）;处理组1、2均可显著延缓冷鲜鸡肉贮藏过程中TBARs值的增加（P＜0.05）,且处理组1效果更好;处理组1、2均可显著抑制冷鲜鸡肉贮藏过程中a*的下降;总体来讲,保鲜效果最好的为处理组1（5% O2＋40% CO2＋55% N2）。     

低温结合气调包装处理对鲜切胡萝卜品质的影响

该研究以鲜切胡萝卜为对象,采用低温结合气调包装对鲜切胡萝卜进行处理,研究不同保鲜方式对鲜切胡萝卜品质的影响.鲜切胡萝卜经气调(气体组成分别为5％O2+5％CO2+90％N2、5％O2+10％CO2+85％N2、10％O2+5％CO2+85％N2)包装后,(4±1)℃下在保鲜盒中贮藏,每3 d测定感官品质、失重率、可溶性...     

鲜切莲藕气调包装及其质量评价

采用9组不同初始气份对鲜切莲藕进行气调包装,放置在5℃、相对湿度为85%环境中贮藏,分别在第2、5、10、15、20 d测定其感官指标、色差、失重率、硬度、VC和酸含量指标,并与未包装产品进行比较;采用主成分分析法对贮藏20 d后的鲜切莲藕质量变化率进行综合评价.结果表明:总体上气调包装对鲜切莲藕有保鲜作用,其中气调组分2%氧气 6%二氧化碳对鲜切莲藕保鲜效果最好.     

臭氧水处理结合气调包装对鲜切生菜保鲜效果的影响

研究臭氧水处理结合气调包装对鲜切生菜在4℃贮藏下的保鲜效果。结果表明,臭氧水处理结合气调包装相比于对照组可以有效抑制鲜切生菜组织中细菌的生长繁殖、水分的流失、叶的降解以及多酚氧化酶的活性,降低鲜切生菜腐败、萎蔫、黄化、褐变的速度,维持鲜切生菜的感官品质,同时也有效抑制了鲜切生菜中VC的氧化分解,延长了货架期,使鲜切生菜在贮藏第14天仍具商品价值。另外,研究结果显示在适当低浓度(5%~10%)的O2和CO2比例范围内,经过长时间(6d以上)贮藏后,不同的气调比例对鲜切生菜品质没有显著的影响。     

自发气调包装对鲜切白菜货架期的影响

为延长鲜切白菜的货架期,本文采用不同透气率和不同面积的气调窗与包装袋相结合进行试验,通过对鲜切白菜包装袋内感官品质、气体成分进行统计和分析,筛选和优化出鲜切白菜最适宜的气调包装。结果表明：自发气调包装可有效改善鲜切白菜贮藏品质,鲜切白菜适宜选用O2和CO2透过速率分别为4×105和1.6×106 cm3/m2?d?atm,透气比为1:4气调窗,所需要气调窗的面积为1~2 cm2/kg,在4 ℃条件下至少可延长货架期4 d;综合计算气调窗和薄膜的透气量可知,适于鲜切白菜包装袋O2和CO2的透过量应分别为1.85×103~2.08×103 和8.59×103~9.51×103 cm3/kg?d?atm,达到鲜切白菜的适宜气体浓度,O2为3.63%~5.10%,CO2为7.77%~8.07%。研制的自发气调包装袋可使鲜切白菜处于适宜的气体状态,可很好地解决包装袋内由于无氧呼吸产生的异味问题,且保留原有的鲜切白菜气味,延长其货架期,为鲜切企业提供有力的技术支持。     

气调包装中气体浓度对牛肉保鲜的影响

研究了气调包装中不同气体浓度对牛肉保鲜效果的影响。运用均匀设计法,对新鲜牛肉分别进行不同水平的气调保鲜包装(O2与CO2浓度在0%～100%均匀分布),在(4±1)℃贮藏过程中,隔天对包装内的气体浓度、牛肉的菌落总数、pH值、TVB-N值、液汁流失率、红度值等指标进行测定分析,并采用重回归分析法找出气调包装中O2浓度、CO2浓度、贮藏时间与菌落总数之间的关系式。结果表明:高氧或高CO2浓度的气调包装对牛肉保鲜效果都不理想,而适当的气体组合45%O2/30%CO2/25%N2的气调包装牛肉货架期最长。     

新鲜猪肉气调保鲜包装技术与设备

本文介绍鲜猪肉气调保鲜包装混合气体的组成、保持鲜肉色泽与防腐保鲜效果和GM型气体比例混合器的结构与性能。通过鲜猪肉的气调包装和真空包装保鲜效果试验得出：在0～6℃温度贮藏14天后，两种包装的保鲜和保持色泽的效果相比较，气调包装鲜猪肉的细菌总数低于真空包装，血色素的指标是真空包装的三倍。研制的GM型气体比例混合器，可使二种气体（O2与CO2或CO2与N2）或三种气体（O2、CO2、N2）任意体积比例混合，气体比例混合的精度（±1％，其标准流量在0．1MPa压力下为2．4m3／h）GM型气体比例混合器的供气量可满足热成型真空充气包装机或其他机型的气调包装操作要求。     

O2/CO2气调下西兰花能量代谢与贮藏品质的关系

能量在果蔬保鲜及衰老过程中起着至关重要的作用,为研究O2/CO2气调对西兰花能量代谢及保鲜效果的影响,本实验以自然空气为对照（CK）,研究体积分数20% O2＋80% CO2、50% O2＋50% CO2、80% O2＋20% CO2气调环境对西兰花10 ℃贮藏过程中pH值和丙酮酸脱氢酶（pyruvate dehydrogenase,PDH）、琥珀酸脱氢酶（succinate dehydrogenase,SDH）和细胞色素c氧化酶（cytochrome c oxidase,CCO）活力及能荷水平、色调（H值）、VC含量和水分质量分数的影响。结果表明：与50% O2＋50% CO2处理组相比,过高比例的CO2（20% O2＋80% CO2）处理可引起西兰花pH值的明显降低,进而造成PDH、SDH和CCO活力的下降和能荷水平的降低,最终造成贮藏期间西兰花VC含量、色调和水分质量分数的下降;过高比例的O2（80% O2＋20% CO2）处理虽在贮藏前期提高了PDH、SDH和CCO活力,但在后期迅速下降,不利于建立平稳而持续的能量供应体系。适宜的O2/CO2气调如50%O2＋50% CO2则可调节西兰花体内pH值和呼吸关键酶活力,建立持续稳定的能量供应体系并很好地维持西兰花贮藏品质。相关性分析表明,能荷水平与西兰花VC含量、色调和水分质量分数具有很高的正相关性,相关系数最高达0.996,因此,能荷变化可作为判断西兰花贮藏条件优劣的衡量指标。     

高浓度二氧化碳气调包装通过调节酚代谢抑制鲜切莲藕的酶促褐变

鲜切莲藕褐变的主要原因是酶促褐变,高浓度CO_2气调包装(Modified-atmosphere packaging,MAP)可以有效延缓鲜切果蔬褐变,而苯丙氨酸解氨酶(L-phenylalanine ammonia-lyase,PAL)、多酚氧化酶(Polyphenol oxidase,PPO)和过氧化物酶(Peroxidase,POD)的编码基因是引起果蔬褐变的主要基因。然而,高浓度CO_2 MAP对鲜切莲藕片PAL、PPO、POD酶及其编码基因表达的影响却鲜有报道。本文分析了100%CO_2MAP对鲜切莲藕贮藏过程中褐变度、总酚含量、PAL、PPO和POD酶活性及其编码基因表达的影响。结果表明:100%CO_2 MAP对延缓鲜切莲藕褐变有较好效果,且100%CO_2 MAP贮藏期间鲜切莲藕PAL、PPO和POD酶活性随褐变程度的增加而同步变化。此外,Nn PAL1,Nn PPOA和Nn POD2/3的表达变化与PAL,PPO和POD酶活性的变化及褐变相一致,说明高浓度CO_2 MAP可能通过下调Nn PAL1,Nn PPOA和Nn POD2/3的表达来延缓鲜切莲藕褐变。     

四种不同气调包装的冷却猪肉在冷藏过程中的理化及感官变化

冷却猪肉分别采取真空包装、CO-MAP(CO+CO2+N2)包装、高氧-MAP(高浓度O2+CO2+N2)和低氧-MAP(低浓度O2+CO2+N2)包装后,在(4±1℃)贮存三周,每周测定各项理化指标(TVB-N和TBARS),并进行感官评定。结果表明:1)采用CO-MAP包装的冷却猪肉在贮存过程中不仅TVB-N和TBARS较低,而且红色稳定无任何异味。2)真空包装组的冷却猪肉在贮存期间TVB-N和TBARS也较低,在贮存末期呈淡紫色有轻微异味。3)含氧气调包装中,冷却猪肉的TVB-N值和TBARS值相对较高,特别是脂肪氧化加速,鲜红色泽1周后很快变为褐色,并有不良气味产生,所以含氧包装仅适合保质期在1周以内的冷却猪肉。     

不同气调包装对冷却猪肉在冷藏过程中的微生物变化的研究

冷却猪肉分别采取真空包装、CO-MAP(CO+CO2+N2)包装、高氧-MAP(高浓度O2+CO2+N2)和低氧-MAP(低浓度O2+CO2+N2)包装后,在(4±1℃)贮存三周,每周测定各项微生物的变化。结果表明:1)CO-MAP和真空包装在贮存末期的优势菌为乳酸菌而含氧气调包装的优势菌是假单胞菌属。2)CO-MAP组可抑制腐败细菌的生长除对乳酸菌抑制作用较弱外,对假单胞菌、肠杆菌科菌均具有很强的抑制作用,其对腐败菌的抑制作用明显好于真空包装组。     

高氧气调包装对鲜切莴苣抗氧化活性的影响

研究60% O2＋20% CO2＋20% N2和100% O2高氧气调包装的鲜切莴苣在4℃贮藏14d期间抗氧化能力的变化,以空气包装的鲜切莴苣为对照。结果表明：高氧气调包装对鲜切莴苣的抗氧化活性有明显影响,60% O2＋20% CO2＋20% N2和100% O2高氧气调包装抑制了VC及其对DPPH自由基清除率的下降,促进类胡萝卜素及其对DPPH自由基清除率的下降,促进了多酚及其对DPPH自由基清除率的上升,从而抑制了鲜切莴苣抗氧化活性的下降。统计分析表明,VC与DPPH自由基清除能力间呈显著的线性正相关关系,相关系数为0.8745,说明高氧气调包装抑制鲜切莴苣抗氧化活性的下降与其抑制VC含量的下降有关。     

Effects of chitosan-based coating and modified atmosphere packaging (MAP) on browning and shelf life of fresh-cut lotus root (Nelumbo nucifera Gaerth)

The present study investigated the effect of chitosan coating containing antibrowning agents and modified atmosphere packaging (MAP) on the browning and shelf life of fresh-cut lotus root stored at 4 °C for 10 days. The atmosphere in the packages was evaluated for O₂ and CO₂ concentrations. The browning on the surface of lotus root slices was prevented by chitosan-based coating and MAP treatment. L* values of coated + MAP and control samples were 68.8 and 48.9 after 8 days storage, respectively. For a^? and b^? values, samples of coated + MAP treatment had the slowest increasing trends among all the treatments. At the end of storage, the coated + MAP samples exhibited the lowest polyphenol oxidase (PPO) activity and malondialdehyde (MDA) content. Its highest overall visual quality (OVQ) scores (> 7) demonstrated that chitosan-based coating + MAP treatment could provide a better inhibitory effect on the browning and extend the shelf life of fresh-cut lotus root.Industrial relevance: Fresh-cut vegetables have drawn the attention of industry as a novel lightly processed product. Both edible coating and MAP treatment cause changes in atmosphere composition and respiration rate of lotus root slices. This combined treatment could be used to control the browning and improve the storage life of this fresh-cut vegetable. This information could be useful for the development of novel application to edible coating and MAP design for lightly processed lotus root.     

二氧化碳气调包装对鲜切结球莴苣贮藏品质和生理的影响

研究4℃、10% O2结合不同体积分数CO2(10%～50% CO2)处理对鲜切结球莴苣的主要品质和生理指标变化的影响。结果表明：高体积分数CO2导致了细胞膜通透性增加;10% O2＋30% CO2气体组合显著抑制了多酚氧化酶、过氧化物酶和过氧化氢酶的活性,延缓了组织的衰老和褐变,并较好地保持了鲜切结球莴苣中叶绿素、VC和还原糖含量。感官评价结果表明,在10% O2＋30% CO2气体组合条件下,鲜切结球莴苣贮藏15d仍具有商品价值。     

Effect of packaging conditions on shelf-life of fresh foal meat

The objective was to determine the shelf life of foal meat (Longissimus dorsi) stored in four different packages: (i) vacuum, (ii) overwrap and (iii) two modified atmospheres (MAP): high O(2) MAP (80% O(2)+20% CO(2)) and low O(2) MAP (30% O(2)+70% CO(2)) stored at 2 °C during 14 days. Shelf life evaluation was based on pH, colour, lipid and protein oxidation, microbial counts and sensory assessment of odour, colour and appearance. Based on aerobic bacterial counts, the shelf life of foal meat samples in overwrap and high O(2) MAP packages would be 10 days at most, almost 14 days in low O(2) MAP and more than 14 days in vacuum packaging. Scores for sensorial evaluation were unacceptable after 10 days of storage in samples in overwrap and MAP packs, but they were still acceptable in vacuum ones. Moreover, for all packaging conditions except vacuum, which remained constant, a decrease in redness (a*) and an increase in carbonyl content and TBAR'S values was observed with storage time. High O(2) levels negatively affected foal meat quality, while anaerobic conditions extended shelf life to 14 days.     

气调包装对大菱鲆的冷藏保鲜效果

以大菱鲆为研究对象,通过不同气调包装（60% CO2＋5% O2＋35% N2、60% CO2＋30% O2＋10% N2、40% CO2＋30% O2＋30% N2）进行处理,测定其感官、菌落总数、pH值、挥发性盐基氮（TVB-N）值、硫代巴比妥酸（TBA）值、汁液流失率等指标变化,综合评价气调包装对冷藏大菱鲆的保鲜效果。结果表明：空气包装组大菱鲆冷藏货架期为4 d,60% CO2＋5% O2＋35% N2气调包装组的保鲜效果最佳,货架期约为8 d;气调包装中高体积分数的CO2抑菌效果较为明显,能有效延缓pH值、菌落总数与TVB-N值的升高,但较高含量的CO2会导致鱼肉汁液流失较为严重;在鱼肉脂肪氧化方面,O2较CO2作用更大,高含量的O2对脂肪氧化具有一定促进作用;60% CO2＋5% O2＋35% N2气调包装组冷藏贮存8 d,大菱鲆的菌落总数为6.69（lg（CFU/g））,TVB-N值为11.99 mg/100 g,TBA值为2.34 mg/100 g。总体结果表明,气调包装能显著延长冷藏大菱鲆货架期,具有良好的保鲜抑菌作用。     

Effect of packaging atmosphere on the microbial attributes of pearlspot (Etroplus suratensis Bloch) stored at 0-2 degrees C

Effect of packaging atmosphere (air and under different modified atmospheres (MAs), 40% CO2/60% O2, 50%/50% O2, 60% CO2/40% O2, 70% CO2/30% O2 and 40% CO2/30% O2/30% N2) on the microbial and biochemical attributes of fresh pearlspot (Etroplus suratensis Bloch) stored at 0-2 degrees C was investigated. Trimethylamine nitrogen (TMA-N) and thiobarbituric acid (TBA) values remained lower than the proposed acceptability limits throughout the storage period. Results demonstrated that storage of pearlspot under air and MA 40% CO2/30% O(2)/30% N(2) resulted in growth of Enterobacteriaceae, Aeromonas and H(2)S-producing bacteria including Shewanella putrefaciens, while all other packaging atmospheres did not allow multiplication of Enterobacteriaceae and Aeromonas within 3 weeks. Aeromonas spp. identified were Aeromonas hydrophila, Aeromonas veronii biovar sobria and A. veronii biovar veronii. Significant reduction (p<0.01) was noticed in Aeromonas population of pearlspot stored under MA 60% CO2/40% O2 and 70% CO2/30% O2. A delay of growth of Pseudomonas below 5.0log(10)cfug(-1) was observed during the 15th day of storage at 0-2 degrees C under modified atmosphere packaging (MAP) conditions. Growth of faecal streptococci was significantly inhibited in all the packaging atmospheres at 0-2 degrees C during the entire storage period. Survival of coagulase positive Staphylococci (<50cfug(-1)) in low numbers was noticed during storage in all the packaging atmospheres. Clostridium botulinum toxin was not detected. All the packaging atmospheres did not allow multiplication of sulphite-reducing clostridia at 0-2 degrees C during the entire storage period. Packaging in MA 60% CO2/40% O2 resulted in the inhibition of growth of Aeromonas and Enterobacteriaceae, and the slowest growth of psychrotrophic bacteria, H(2)S-producing bacteria, including Shewanella putrefaciens and Pseudomonas and extended microbiological shelf life to 9-10 days. This study confirms the survival of potentially pathogenic A. hydrophila, A. veronii biovar sobria and A. veronii biovar veronii capable of growth at low temperature in pearlspot stored under MA.