Analysis of quality-related proteins in golden pompano(Trachinotus ovatus)fillets with modified atmosphere packaging under superchilling storage

Here,we aimed to study the changes in proteome of golden pompano fillets during post-mortem storage.Tandem mass tags(TMT)-labeled quantitative proteomic strategy was applied to investigate the relationships between protein changes and quality characteristics of modified atmosphere packaging(MAP)fillets during superchilling(-3°C)storage.Scanning electron microscopy was used to show that the muscle histology microstructure of fillets was damaged to varying degrees,and low-field nuclear magnetic resonance was used to find that the immobilized water and free water in the muscle of fillets changed significantly.Total sulfhydryl content,TCA-soluble peptides and Ca2+-ATPase activity also showed that the fillet protein had a deterioration by oxidation and denaturation.The Fresh(FS),MAP,and air packaging(AP)groups were set.Total of 150 proteins were identified as differential abundant proteins(DAPs)in MAP/FS,while 209 DAPs were in AP/FS group.The KEGG pathway analysis indicated that most DAPs were involved in binding proteins and protein turnover.Correlation analysis found that 52 DAPs were correlated with quality traits.Among them,8 highly correlated DAPs are expected to be used as potential quality markers for protein oxidation and water-holding capacity.These results provide a further understanding of the muscle deterioration mechanism of packaging golden pompano fillets during superchilling.

Monitoring and identification of spoilage-related microorganisms in braised chicken with modified atmosphere packaging during refrigerated storage

This study mainly monitored the dominant bacterial populations and identified the spoilage-related microorganisms of braised chicken meat stored under different CO_(2)-modified atmosphere packaging(MAP)during refrigerated storage using a culture-dependent method and 16S rDNA identification.The quality changes and shelf life of the meat were also measured.The growth rate of total viable count(TVC)in braised chicken was slower with an increase of CO_(2) content in MAP,which also occurred in the remaining bacterial species monitored(lactic acid bacteria,Pseudomonas spp.,Brochothrix thermosphacta).The MAP exerted beneficial effects on the quality of braised chicken,as demonstrated by retarding the production of total volatile basic nitrogen(TVB-N)and delaying lipid oxidation(TBARS test).A total of 14 isolates were identified from braised chickens with different packaging at the end of storage,these included P.fragi(6 isolates),P.psychrophila(2 isolates),Enterococcus faecalis(3 isolates),B.thermosphacta(2 isolates),Staphylococcus equorum(1 isolate).

Effects of Carbon Dioxide Treatment and Modified Atmosphere Packaging on the Quality of Long Distance Transporting “Maehyang” Strawberry

This study was conducted to investigate the effects of carbon dioxide (CO2) and modified atmosphere (MA) packaging on the quality of strawberry during long distance transportation. “Maehyang” strawberries (Fragaria x ananassa Duch.) with red color on 70% of the fruit surface were harvested in Gyeongnam province, Korea. The samples were placed in gas-tight chamber with 30% CO2 concentration for 3 hours at 3°C. Strawberry samples were then packaged with modified atmosphere-modified humidity (MA/MH) packaging film. Samples treated with CO2 alone and combined CO2 with MA packaging were stored for one day at 1°C, transported for 10 days at 1°C, and distributed for 3 days at 4°C. Carbon dioxide alone or combination with MA packaging was effective in maintaining quality of “Maehyang” strawberries. Carbon dioxide treatment significantly increased firmness and reduced softening index and decay rate during 14 day transportation and distribution. Samples treated with CO2 + MA had higher overall score with low softening index and weight loss after 14 days of transportation and low temperature distribution compared to CO2 treatment only. The results indicated that a short term application of CO2 or combination treatment of CO2 and MA could be good postharvest handling for maintaining freshness of “Maehyang” strawberries during long distance vessel export.

Effects of Active Modified Atmosphere Packaging on Postharvest Quality of Shiitake Mushrooms (Lentinula edodes) Stored at Cold Storage

The effects of active modified atmosphere packaging （MAP） on the postharvest quality of shiitake mushrooms stored at cold temperature （4°C） were investigated.The gas components were 2% O2 ＋7% CO2 （MAP1）,2% O2 ＋10% CO2 （MAP2） and 2% O2 ＋13% CO2 （MAP3）,respectively.The results showed that active MAP could extend the shelf-life of shiitake mushrooms to 17 d and the concentration of carbon dioxide could influence the postharvest quality of shiitake mushrooms.MAP2 treatment inhibited the increase in respiration rate and malondinaldehyde （MDA） contents,delayed the decrease in firmness,soluble sugar and vitamin C,and obviously reduced the activity of polyphenol oxidase （PPO） and the degree of browning,therefore maintaining better quality.

Effects of 1-methylcyclopropene and modified atmosphere packaging on fruit quality and superficial scald in Yali pears during storage

The Yali pear（Pyrus bretschneideri Rehd.） is susceptible to superficial scald during prolonged cold storage and at shelf life. This study investigated the effects of 1-methylcyclopropene（1-MCP） and modified atmosphere packaging（MAP） on changes of fruit quality and superficial scald during cold storage and at shelf life in Yali pear. Compared with MAP, the combination of MAP and 1-MCP（MAP＋1-MCP） treatment reduced the carbon dioxide and ethylene content inside the packaging bag. The 1-MCP, MAP, and MAP＋1-MCP treatments reduced the superficial scald index, malondialdehyde content, O2^-· production rate and relative conductivity and inhibited the accumulation of α-farnesene and conjugated trienes in the peel. 1-MCP and MAP＋1-MCP treatments maintained a higher phenolic content and enhanced the catalase and superoxide dismutase activities in the fruit, while reduced activities of lipoxygenase and polyphenol oxidase in the peel preceding the onset of superficial scald. Comprehensive analysis indicated that the MAP＋1-MCP treatment is the most effective method tested for improving the quality of Yali pears during cold storage and at shelf life.

Using a Modified Soil-Plant-Atmosphere Scheme(MSPAS)to Simulate the Interaction between Land Surface Processes and Atmospheric Boundary Layer in Semi-Arid Regions

This paper uses a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to study the interaction between land surface and atmospheric boundary layer processes. The scheme is composed of two main parts: atmospheric boundary layer processes and land surface processes. Compared with SiB and BATS, which are famous for their detailed parameterizations of physical variables, this simplified model is more convenient and saves much more computation time. Though simple, the feasibility of the model is well proved in this paper. The numerical simulation results from MSPAS show good agreement with reality. The scheme is used to obtain reasonable simulations for diurnal variations of heat balance, potential temperature of boundary layer, and wind field, and spatial distributions of temperature, specific humidity, vertical velocity, turbulence kinetic energy, and turbulence exchange coefficient over desert and oasis. In addition, MSPAS is used to simulate the interaction between desert and oasis at night, and again it obtains reasonable results. This indicates that MSPAS can be used to study the interaction between land surface processes and the atmospheric boundary layer over various underlying surfaces and can be extended for regional climate and numerical weather prediction study.

Using a Modified Soil-Plant-Atmosphere Scheme (MSPAS) to Study the Sensitivity of Land Surface and Boundary Layer Processes to Soil and Vegetation Conditions

A series of sensitivity tests are performed to test the stability and sensibility of the Modified Soil-Plant-Atmosphere Scheme (MSPAS), which was wholly introduced in a previous paper. The numerical simulation results from the experiments show good agreement with physical reality. Besides, some of the results are illuminating. Together with the first paper, it is concluded that MSPAS is a simple but effective model, and it is practically valuable in the research work of desertification control and reforestation in China.

Prolonging the Shelf Life of Ready-to-Serve Pizza through Modified Atmosphere Packaging: Effect on Textural and Sensory Quality

The effects of different modified atmospheres (air: atm1;100% CO2: atm2;100% N2: atm3;50% CO2/50% N2: atm4) on the textural and sensory characteristics of the ready-to-serve pizza at 7℃ ± 1℃ were investigated. The values of hardness, gumminess and chewiness were found to be increased during the storage period while cohesiveness and springiness exhibited a decreasing trend. Overall, the 100% CO2 product yielded the best textural and sensorial characteristics followed by 50%CO2/50% N2 and 100% N2 when compared to conventional packed pizza at 7℃ ± 1℃. Carbon dioxide caused microbial inhibition as well. The shelf life of ready-to-serve pizza significantly increased upto 45 days (a 300% increase) for the samples packaged under 100% CO2 (atm2), 50% CO2/50% N2 (atm4) and 100% N2 (atm3), compared to conventional air pack (15 days).

Effects of Lactoperoxidase System Activation-Oregano Essential Oilor Chlorine on the Quality of Modified Atmosphere Packaged Fresh-Cut Iceberg Lettuce

The present work focused on the effects of the Modified Atmosphere Packaging (MAP) 1 (5% O2 and 10% CO2) or 2 (2% O2 and 5% CO2) and the previous addition of Lactoperoxidase System (LPS) and Oregano essential oil or chlorine washing on the quality of fresh-cut lettuce during refrigerated storage at +4?C. Our results showed the significant effect of this combined treatment on quality improvement during storage. Thus, mesophilic bacteria was reduced in treated samples compared to those untreated with number which not exceeded the critical of 5 × 107 UFC?g-1 (p 2 and CO2 levels created by both atmosphere were not significantly different between the two treatments (p > 0.05). Brightness of lettuce samples was significantly reduced during storage. Thereafter, the PCA data showed the effect of combined treatment on the preservation of hygienic, physico-chemical and sensory quality up to the 7th day of refrigerated storage of these treated samples. The results obtained draw attention to modified atmosphere packaging lettuce and the addition of bio-preservatives which could be an alternative of choice to replace chlorine to preserve the sanitary quality of green products.

Effect of Modified Atmosphere Packaging on Postharvest Quality of Rambutan cv. Binjai

An experiment on retail film packaging system was conducted to compare the atmospheric composition within sealed packs containing rambutan fruits. This research was done in order to study the effect of packaging films with different permeability on the some of physicochemical properties of rambutan during storage at 10℃. The films used were 0.090 mm low density polyethylene （LDPE）, 0.040 mm polyprophylene and 0.057 mm LDPE compared unwrapped fruits. Fruits were evaluated every 5 days for changes in moisture content, total sugars, vitamin C, hardness and color. Unwrapped rambutan had severe browning after 10 days. Sealed packages especially the LDPE had delayed the development of the browning for 20 days of storage and had the lowest weight loss.

Microbial Aspects in Comparing Modified Atmosphere Packaging and Vacuum Packaging on Shelf Life of Fresh Bull Meat

The importance of meat preservation and various reports on different types of packaging, and to compare the effects of modified atmosphere packaging （MAP） and vacuum packaging （VP） on shelf life of flesh bull meat, and microbiological tests on meat together with some chemical and sensory tests was on tight observation. It was an experimental study, 96 samples were randomly packaged in two groups of MAP and VP equally. The package consists of five layers which are Polyvinylidin Chloride （PVDC）, Ethyl Vinyl Alcohol （EVOH）, Poly Ethylene （PE）, Linear Low Density Poly Ethylene （LLDPE）, and poly Amid （PA）, respectively. MAP meat with 700 mL of CO2 per kg of meat. The packaging were made in at-ameh-pars factory and transported in chilled condition to a well prepared refrigerator in National Research Institute of Food Science （NRIFS） of Shahidbeheshti University of Medical Sciences. These samples tested weekly, since first day after packaging, and week 2, 3, 4, 5, 6, 7, and 8. Microbial tests include Total Microbial, Coliform, Lactic Acid Bacteria, Pseudomonas Counts, and Clostridium. Chemical and sensory tests also carried out. Total volatile bases （TVN）, TBA, and pH as chemical analyses and color, odor, and weep as sensory analyses are also added. Results revealed that total microbial count was in standard range within the 6 weeks for VP, and 5 weeks for MAP technique. Other microbial factors including coliforms, lactic acid bacteria are less and somehow in chemical and sensory tests emphasized the microbial figures. recommended for meat packaging. similar pattern to total count, and no clostridia were found. By the way, The results showed that according to our existing facilities, VP is

Effect of Modified Atmosphere Packaging on Postharvest Quality of Barangan Banana

An experiment retail film packaging system was used to compare the atmospheric composition within sealed packs containing barangan banana fruits. This research was done in order to study the effect of packaging films with different permeability properties on the physicochemicalproperties of barangan banana during storage at room temperature （28 ± 2 °C） and at 15 °C. The films used were 0.09 mm low density polyethylene （LDPE）, 0.04 mm polypropylene and 0.057 mm LDPE compared with unwrapped fruits as control. Barangan bananas were evaluated each 5 days intervals for changes in moisture content, total sugars, vitamin C, hardness and color. Unwrapped barangan bananas were overripe and soft after 15 days at both temperature conditions. Sealed packages especially using LDPE at 15 °C delayed the development of the yellow color of banana until 20 days of storage and had the lowest weight loss.

Statistical Investigation and Mapping of Monthly Modified Refractivity Gradient over Pakistan at the 700 Hectopascal Level

This study is an effort to investigate the spatial-temporal variability of the modified refractivity gradient at the 700 hPa pressure level over Pakistan and its neighbouring regions of Afghanistan, India, Iran and the Arabian Sea using the remote sensing data of the AQUA (AIRX3STM) satellite from 2008 to 2012. Trapping conditions only found in December were spread over Khyber Pakhtunkhwa (Gilgit-Baltistan, Pakistan) with an average value of -182.042 M/Km and showing Leptokurtic distributions. The lowest monthly average value super-refractive conditions existed in the autumn season with a strong monthly correlation (>0.91 M/Km). A very high monthly correlation (0.9 M/Km) was found for the super-refractive conditions over the whole time period. The largest spatial and temporal normal conditions appeared in January with the average value for normal conditions being 132.72 M/Km (found over Zabul, Afghanistan) with Leptokurtic distributions. During May normal conditions were the smallest in spatial extent over Pakistan, India and Afghanistan, showing Platykurtic distributions. Sub-refractive conditions mostly prevailed at all times. The probability for extreme sub-refractive conditions was very high in 2008-2012. The highest average sub-refractive conditions appeared in the winter and autumn seasons (spread around Quetta and Kalam, Pakistan). The highest monthly average sub-refractive conditions with a value of 1,265,188 M/Km were found in January and spread around the Sarbaz River Iran. Correlations for the existence of sub-refractive conditions varied from 0.8 M/Km (moderate strong) to 0.4 M/Km during the autumn to winter season. Permanent super-refractive conditions existed over Baluchistan from February to September.

不同MA袋对鲜食核桃仁保鲜效果的比较

测定不同材质自发气调(modified atmosphere,MA)包装袋对鲜食核桃仁的保鲜效果。以‘香玲’鲜食核桃为试材,分别采用5种不同塑料复合包装袋包装:PA/PE袋-200μm(处理1),PA/PE袋-180μm(处理2),Al/PET袋-210μm(处理3),PET/PE袋-160μm(表面平滑)(处理4)和PET/PE袋-160μm(表面网纹)(处理5),以地膜包装-6μm(处理6)为对照,低温贮藏,定期测定其呼吸强度、脂肪含量、蛋白质含量、SOD酶活性、POD酶活性、酸价、过氧化值及碘价等指标的变化。结果表明:呼吸强度测试中,除处理3外,处理6和其他处理组在贮藏期前12天内呼吸强度从135 CO_(2)mg/(kg·h)下降至60 CO_(2)mg/(kg·h)以内,中后期几乎保持稳定状态;处理4和处理5核桃在贮藏15天后呼吸强度在30~40 CO_(2)mg/(kg·h)之间;脂肪含量测试中,在贮藏30天内处理3的核桃脂肪含量为34.2 g/100 g;处理1、2、4、5的核桃在贮藏前期脂肪含量持续下降,60天时,处理4、5核桃脂肪含量分别为45.8 g/100 g和46.1g/100 g;在贮存60天时,蛋白质含量处理4、5核桃的蛋白质含量最高,达到17.6 g/100 g和17.1 g/100 g;酸价测试中,在贮藏期间处理6核桃仁的酸价从0.24 mg KOH/g增长到4.3 mg KOH/g,处理4、5核桃的酸价从0.24 mg KOH/g增加到2.7 mg KOH/g以内;SOD酶活性测试中,处理6对照组和处理1、2在贮藏30天时,SOD酶活性达到140.1 U/g和135.2 U/g;处理3、4、5的SOD活性在贮藏45天分别达到139.9、149.7 U/g和150.0 U/g;POD酶活性测试中,处理6对照组和处理3在贮藏30天时,POD活性达到最低值,分别为10.5 U/g和10.7 U/g,其他4组在45天时降至最小值,分别为:10.8、11.0、10.1、10.3 U/g;MDA含量测试中,整个贮藏期,鲜食核桃核仁的MDA含量持续上升,贮藏至60天时,处理4的MDA含量为6.25 mmol/g,处理5为6.08 mmol/g,均低于其他组数据,但差异不显著。上述6种包装材料中,PET/PE-160μm包装保鲜效果最佳,可以推广使用。

STUDY ON THE MODIFICATION OF POLY (METHYL METHACRYLATE) TRANSPARENT MATERIAL

A kind of transparent plastic material has been prepared with bulk copolymer of MMA-MA containing MA 20 vol% as matrix modified by introducing EtOH during bulk copolymerization to increase the transparency and by copolymerizing together with metallic salts of MA forming ionomer polymer to improve the heat-tolerance and hardness. The effect of the contents of the additives on the heat stability, hardness and transparency of the copolymer has been studied. The optical homogeneity of the copolymer material has also been examined. It has been found that the specific property of transparent material of this kind may be obtained by controlling the amounts of EtOH and metallic salt of MA.

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(CO_(2):10%~14%;O_(2):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℃(CO_(2):10%~12%;O_(2):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。

不同浓度1-甲基环丙烯处理对蓝莓贮藏品质的影响

为探究不同浓度1-甲基环丙烯(1-MCP)结合自发气调包装(MAP)对蓝莓冷藏期间保鲜效果的影响,以‘莱克西’蓝莓为试材,采后2 h内入预冷库,装入气调箱并对其进行0.5、1.0、1.5μL/L 1-MCP处理,冷链车运输96 h后入冰温库((-0.5±0.3)℃)贮藏,每10 d测定蓝莓的品质指标、生理指标和挥发性成分。结果表明:MAP结合3种浓度1-MCP处理均能延缓蓝莓果实硬度的下降,保持相对较高的花色苷、VC、可溶性固形物、可滴定酸含量,抑制呼吸峰值和乙烯生成速率。利用SPSS主成分分析得出各处理的保鲜效果排序为:MAP+1.0μL/L 1-MCP>MAP+1.5μL/L 1-MCP>MAP+0.5μL/L 1-MCP>MAP。在蓝莓贮藏过程中醛类(52.34%~86.13%)和萜类(7.26%~32.44%)是其主要挥发性成分,MAP+1.0μL/L 1-MCP处理的蓝莓果实能保持较高的醛类物质和萜类物质相对含量。综上,MAP结合1.0μL/L 1-MCP处理对蓝莓的保鲜效果最佳。

西兰花自发气调保鲜数学模型建立

针对西兰花自发气调保鲜缺乏理论模型与定量依据,导致包装系统设计失误或失败的问题,以甘肃高原夏菜特色蔬菜“耐寒优秀”西兰花为研究对象,通过密闭系统法测算西兰花在不同温度(0、5、10、15、20℃)条件下的呼吸速率;基于使用的方便性、与已有呼吸数据的吻合性以及涵盖因素的全面性,选择建立基于酶动力学理论的非竞争型和化学动力学理论的西兰花的呼吸速率模型,各温度下两种模型的决定系数均大于0.90,并通过模型相关统计指标及预测值与试验值的对比,检验模型预测准确性与推广泛化能力。结果表明,选用非竞争型酶动力学模型表征西兰花实际呼吸速率特性,以12℃贮藏温度为例,将已建立的非竞争型酶动力学呼吸速率模型与气调包装气体交换模型相结合,建立西兰花自发气调贮藏的预测模型,并运用该预测模型设计12℃贮藏温度下西兰花的自发气调保鲜包装系统参数,说明该预测模型的使用方法。

保鲜剂结合不同硅窗面积气调包装对西兰花贮藏品质的影响

为进一步检验前期西兰花硅窗气调关键参数筛选研究结果,并期望得到相较于单一硅窗气调贮藏效果更好的保鲜剂结合硅窗气调包装的西兰花的贮藏方法。以甘肃特色高原蔬菜耐寒优秀西兰花为材料,采用60 mg/L的二氧化氯保鲜剂溶液、蒸馏水浸泡清洗处理,以无处理为对照,再结合2℃下硅窗面积分别为6、8 cm^(2)的硅窗保鲜袋包装,通过叶绿素、抗坏血酸(Vc)、总酚、总花色苷和硫代葡萄糖苷含量等营养指标的测定,考察各处理方法对西兰花25 d贮藏期内品质的影响。结果表明,相较于单一的硅窗气调袋包装保鲜,保鲜剂或蒸馏水清洗处理结合硅窗气调保鲜有更好的保鲜效果,其中60 mg/L的二氧化氯保鲜剂溶液清洗处理效果更优。2℃贮藏温度下,同样处理方式的西兰花,硅窗面积为8 cm^(2)的硅窗袋气调袋包装的保鲜效果要优于硅窗面积为6 cm^(2)的硅窗气调袋包装;60 mg/L的二氧化氯保鲜剂溶液浸泡清洗,结合硅窗面积8 cm^(2)的硅窗气调袋包装的西兰花的贮藏品质最好,在25 d贮藏期内各营养指标总体高于其他处理。

自发气调包装对鲜食竹笋采后贮藏品质和木质化的影响

【目的】鲜食竹笋是未经漂烫杀青、腌制的竹笋产品,具有鲜脆的口感和清爽的风味。但鲜竹笋呼吸旺盛,极易失水萎蔫,难以保鲜,影响其销售。自发气调包装可通过调节内环境的气体成分降低包装果蔬的呼吸强度,研究气调包装处理对鲜食竹笋采后贮藏品质和木质化的影响,为鲜食竹笋的保鲜包装选择提供参考。【方法】采用自发气调保鲜袋(厚度20μm,O_(2)渗透率11643 cm^(3)/m^(2)·d·atm,水蒸气透过率62.586 g/m^(2)·d)包装剥壳鲜竹笋,以尼龙袋抽真空包装为对照,将包装鲜竹笋贮藏于冷库(4±1℃),研究其贮藏期间的品质变化和木质化程度差异。【结果】与传统真空保鲜工艺相比,自发气调包装通过竹笋本身的呼吸作用和膜材料的气体透过性使得袋内形成低O_(2)、低CO_(2)(O_(2)<5%,CO_(2)<5%)的环境,能够显著降低鲜竹笋在贮藏期间的呼吸强度,峰值呼吸强度仅为真空处理的46.93%。贮藏21d时,气调包装显著抑制竹笋的褐变及膜脂过氧化发生,竹笋芯部亮度较采收时仅下降6.17%,而真空包装竹笋下降17.74%,真空包装竹笋的丙二醛含量是气调包装内的2.93倍。在木质化方面,两种包装下竹笋的木质化速度在贮藏14 d时开始上升,真空包装下竹笋木质化关键酶(苯丙氨酸解氨酶、过氧化物酶、肉桂醇脱氢酶)的活性均达到峰值,木质化加剧;而气调包装内竹笋的相关酶活性未出现高峰,酶活性缓慢上升,延缓了竹笋的木质化,可保持竹笋口感鲜脆;在贮藏21 d时,气调包装竹笋木质素含量仅为真空包装竹笋的84.99%,有效延长鲜食竹笋的保鲜期。【结论】自发气调包装袋内低O_(2)、低CO_(2)的气体环境有利于鲜食竹笋的贮藏,竹笋品质和营养成分含量明显优于真空包装处理,应用于鲜食竹笋保鲜具有较好的市场应有前景。