白藜芦醇和壳聚糖复合生物保鲜剂对冷藏鱿鱼品质的影响

为了降低鱿鱼中甲醛含量和改善鱿鱼的贮藏品质,研究了白藜芦醇和壳聚糖对鱿鱼品质和货架期的影响。实验分为对照组、白藜芦醇组(0.2%)、壳聚糖组(1.0%)、白藜芦醇(0.2%+壳聚糖1.0%)组。鱿鱼在(0±0.5) ℃贮藏20 d。以挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBA)、硬度、弹性、甲醛含量的变化、菌落总数(TVC)和感官评分作为评价指标,研究其对鱿鱼的保鲜效果。结果表明:相对对照组,白藜芦醇+壳聚糖显著(p<0.05)降低菌落总数、TVB-N、TBA值和甲醛含量,使硬度和弹性下降程度变缓,显著提高感官评分。白藜芦醇+壳聚糖能够改善鱿鱼的品质,抑制微生物的增殖,并减缓脂肪氧化,延长鱿鱼的货架期,可以用于鱿鱼的保鲜。     

温度和包装对冬枣果实贮藏品质的影响

以初红果期的冬枣为材料,研究了不同贮藏温度(常温、5℃和0℃)和包装(30μm PE和50μm PVC膜)条件下果实失重率、转红率及内含物变化情况。结果表明,低温和包装能够显著抑制果实水分蒸发和果面转红速度,延缓可溶性糖和可滴定酸的转化,保持了较高的维生素C 含量。不同贮藏温度间以0℃效果最好,5℃次之,常温最差;30μm PE包装贮藏效果较好,50μm PVC包装贮藏期不宜超过30d。     

壳聚糖处理对梅杏采后品质的影响

以梅杏为试材,用浓度为0.5、0.75、1.0g/L壳聚糖浸果实1min后进行冷藏,研究壳聚糖处理对梅杏采后贮藏品质的影响。结果表明,以0.75g/L壳聚糖处理效果较好,可降低梅杏的呼吸强度和失重率,抑制细胞膜透性和丙二醛含量的增加,保持较高的硬度、可溶性固形物、可滴定酸、Vc含量,减少梅杏腐烂发生,从而延长贮藏期。     

Effect of temperature fluctuations during frozen storage on the quality of potato tissue (cv. Monalisa)

 Results are presented on the effect of different ranges of temperature fluctuation (–24 to –18°C, –18 to –12°C, –12 to –6°C, –24 to –12°C and –18 to –6°C) on the compression, shear and tension parameters of packed and unpacked frozen potato tissue. The initial temperature, duration and number (2, 4, 8, 16, 24 and 32) of fluctuations were varied. The highest parameter values occurred in samples subjected to fluctuations between –24°C and –18°C, and the lowest values in the range –18 to –6°C. The mechanical strength of the frozen tissue decreased with an increase in the number of fluctuations and in most cases was lower in the packed samples. Moisture loss was greatest in the –18 to –6°C range for pre-packed samples. Changes in the maximum compression force, as a measure mechanical damage, showed the greatest level of significance. Received: 17 June 1997     

Effect of temperature fluctuations during frozen storage on the quality of potato tissue (cv. Monalisa)

 Results are presented on the effect of different ranges of temperature fluctuation (–24 to –18°C, –18 to –12°C, –12 to –6°C, –24 to –12°C and –18 to –6°C) on the compression, shear and tension parameters of packed and unpacked frozen potato tissue. The initial temperature, duration and number (2, 4, 8, 16, 24 and 32) of fluctuations were varied. The highest parameter values occurred in samples subjected to fluctuations between –24°C and –18°C, and the lowest values in the range –18 to –6°C. The mechanical strength of the frozen tissue decreased with an increase in the number of fluctuations and in most cases was lower in the packed samples. Moisture loss was greatest in the –18 to –6°C range for pre-packed samples. Changes in the maximum compression force, as a measure mechanical damage, showed the greatest level of significance. Received: 17 June 1997     

水杨酸处理对梅杏采后贮藏品质的影响

以梅杏为试材,用浓度为0.3、0.5、1.0g/L水杨酸（SA）溶液（清水为对照）浸果实20min后进行冷藏,研究水杨酸处理对梅杏采后贮藏品质的影响。结果表明,0.5g/L水杨酸处理能够较好地降低梅杏的呼吸强度和失重率,抑制细胞膜透性和丙二醛含量的增加,保持较高的硬度、可溶性固形物、可滴定酸、VC含量,减少梅杏腐烂发生,从而延长贮藏期。     

The effects of beeswax coating on quality of Kashar cheese during ripening

The aim of this study was to evaluate the effects of the application of beeswax coating on the microbiological, physicochemical and sensory properties of Kashar cheese during ripening (120 day). Kashar cheeses were coated with two different thickness of beeswax (single‐layer coating, BW1, and double‐layer coating, BW2). For comparison, vacuum packaged (VP) and without packaging material (control) were also studied. Generally, no differences were found in total aerobic mesophilic bacteria, LAB on M‐17 agar, coliform bacteria and S. aureus counts among cheeses. Microbiological analyses also showed the beeswax‐coated cheeses presented a decrease of 2.5 logarithmic units on mould counts compared to control at 120th day. The control cheese had significantly (P < 0.05) higher dry matter, fat and protein contents, followed by BW1. However, the coating reduced formation of a thick crust layer by delaying moisture loss. At the end of 120‐day storage period, no significant differences in pH and acidity values were observed among the cheeses studied. Compared to other cheeses, control and BW1 cheeses had higher levels of WSN and ripening index in the end of storage. In the result of sensory analysis, while cheese BW1 and control were more preferred by the panellists, cheese VP received the lowest scores.     

1‐Methylcyclopropene affects the antioxidant system of apricots (Prunus armeniaca L. cv. Búlida) during storage at low temperature

BACKGROUND: Apricots (Prunus armeniaca cv. Búlida) were treated with 1 mL L^?1 1‐methylcyclopropene (1‐MCP) immediately after harvest and stored in air at 2 °C for 21 days. Antioxidant levels (ascorbic acid and carotenoids), enzymatic antioxidant activities (superoxide dismutase (SOD) and unspecific peroxidase (POX)) and total antioxidant capacity (trolox equivalent antioxidant capacity (TEAC)) were determined. The level of oxidative stress was also established by measuring ion leakage during storage. The changes in the antioxidant potential of apricots were related to the capacity of 1‐MCP to increase their commercial life. RESULTS: 1‐MCP‐treated fruits exhibited higher SOD activity, whereas POX activity was significantly higher only after 21 days at 2 °C. Treated fruits also exhibited better retention of ascorbate and carotenoids and higher TEAC during storage. In accordance with these observations, lower ion leakage values were detected in 1‐MCP‐treated apricots. CONCLUSION: Taken together, these results suggest that 1‐MCP conferred a greater resistance to oxidative stress. This, along with the reduction in ethylene production, could contribute to the increase in commercial life and nutritional value observed in 1‐MCP‐treated apricots. Copyright © 2010 Society of Chemical Industry     

不同愈伤时间对低温贮藏期间马铃薯块茎采后病害及品质的影响

以损伤和无伤马铃薯块茎为试材,研究了不同愈伤时间对低温贮藏期间块茎采后病害和品质的影响。结果表明,愈伤处理可明显减轻损伤和无伤接种马铃薯块茎贮藏期间的采后病害,愈伤时间越长,采后病害的发病率越低,愈伤14d后损伤和无伤接种马铃薯块茎干腐病发病率与不愈伤对照相比分别下降46.2%和55.0%,干腐病病情指数下降49.5%和42.9%,其它病害发病率下降80%和72%。愈伤处理明显降低了损伤接种块茎贮藏期间的失重率、绿化率、发芽率及芽长,愈伤14d后分别比不愈伤对照降低15.2%、48.3%、18.0%和46.2%。但对无伤接种块茎的品质影响不大。损伤块茎干腐病的发病率和病情指数以及其它病害的发病率、失重率均显著高于同期处理的无伤块茎,但绿化率、发芽率和芽长与无伤块茎相比无明显差异。由此表明,愈伤处理可明显减轻马铃薯块茎贮藏期间的采后病害并维持块茎品质。      

MAP结合低温贮藏对高成熟度鲜枣的保鲜效果

研究了以不同体积分数混合的O2、CO2、N2进行气调包装,在(0±0.5)℃贮藏条件下对着色面积在75%以上的全熟鲜枣(Ziziphus zizyphus)品质的影响。结果表明,经过60d的贮藏,不同体积分数的气调包装均能有效抑制全熟鲜枣果实衰老和营养物质损失,能不同程度地延缓果实中MDA(丙二醛)含量的上升和硬度的下降;降低质量损失和乙醇积累量;减缓鲜枣果实中TA(可滴定酸)含量的下降和颜色变化以及还原糖含量的上升;可有效地防止VC、cAMP(环磷酸腺苷)和总黄酮等营养物质的损失;同时能够较长时间保持果实鲜亮的颜色。其中以气体体积分数为5%O2、2%CO2、93%N2的气调包装对全熟鲜枣的保鲜效果最好。      

包装对低温贮藏盐水鸡产品货架期及优势污染菌群的影响

盐水鸡是一种具有客家风味的传统鸡肉制品。为寻找一种能经济、有效地延长冷链销售盐水鸡货架期的包装方式,本文比较了普通包装、真空包装和气调包装对盐水鸡产品理化指标和优势污染菌群的影响。研究结果表明,盐水鸡在低温贮藏期间,各种包装对盐水鸡的含水量、pH和挥发性盐基态氮的影响不显著(p>0.01);在低温贮藏期间,各种包装中好氧性菌落总数呈线性增长,其增长速率为普通包装>气调包装>真空包装。在整个短期低温贮藏期间,没有在各种包装的盐水鸡样品中检测出产气芽孢梭菌,大肠菌群及乳酸菌,但能检测出少量的霉菌和酵母。采用16srDNA序列分析法对各种包装中污染的优势好氧性菌落进行了分类鉴定。鉴定结果表明,各种包装中的优势好氧性菌有Pseudomonas sp., Staphyloccocus aureus,Exiguobacterium sp.,和Carnobacterium sp.,且各种包装中优势菌群存在明显差异。     

Postharvest quality of arazá fruit during low temperature storage

Arazá (Eugenia stipitata Mc Vaugh) fruits at breaker stage of maturity were stored at 7, 10, 12, or 20 °C and 85-90% RH for 2 weeks, with or without an additional simulated shelf-life period (3 days at 20 °C and 70% RH). Some half-yellow (turning) arazá fruit were also stored at 7 or 12 °C. Respiration rate, ethylene production, quality traits and physiological disorders and decay were monitored. Arazá fruit of both stages of maturity showed a climacteric pattern of ripening, with the maximum levels of respiration being reached after 5 days at 20 °C for breaker fruit, while half-yellow fruit ripened totally after one day. Weight loss was the most limiting quality trait for arazá fruit. Chilling injury symptoms included skin scald (only at 7 °C), uneven ripening (at 7 or 10 °C, including uneven softening during storage, particularly in breaker fruit), and slight acidification at 7 °C. Decay in the post-storage shelf-life periods (mainly Gloesporium sp.) was particularly high after storage at 7 °C in breaker fruit. The storage of breaker arazá fruit at 12 °C is recommended because this prevents chilling injury and flesh acidification, and allows normal fruit ripening during a post-storage shelf-life at 20 °C, as revealed by the lower organic acids (mainly malic) content and increased sugar (glucose, fructose and sucrose) content.     

常温不同时期1-MCP处理对苹果贮后货架生理品质的影响

富士苹果采后常温下放置0、5、10 d后进行1-MCP处理,以研究常温不同时期1-MCP处理对富士苹果货架期生理品质的影响。结果表明:1-MCP处理显著延长了货架期,降低了果梗褐变率和腐烂率,维持了较高的可溶性固形物和可滴定酸含量,显著抑制了果实的呼吸强度和乙烯生成速率的增加,并延缓了果皮脆性、果肉平均硬度的下降,有效抑制果实品质的下降。结果还显示:1-MCP的作用效果随着1-MCP处理时期的延迟而下降,在采后10 d处理的效果低于0 d和5 d处理。因此,富士苹果采后应尽快采用1-MCP处理,常温下不超过5d为好。     

不同包装方式对野菜灰绿藜低温贮存品质的影响

研究了在0～4℃低温贮存条件下,保鲜袋开口、密封、打孔3种处理方式对野菜灰绿藜失重率、Vc、可溶性糖、可溶性蛋白质、硝酸盐及亚硝酸盐含量的影响。结果表明,低温贮存条件下,与开口处理相比较,密封处理和打孔处理能有效降低贮存期间灰绿藜的失重率,延缓Vc、可溶性糖、可溶性蛋白质的损失,但对硝酸盐和亚硝酸盐的影响不大;密封处理与打孔处理相比,密封处理能更好地降低灰绿藜低温贮存期间的失重率和可溶性糖的损失,而打孔处理能更好地降低可溶性蛋白质的损失。     

微环境气调对蓝果忍冬贮藏品质和抗氧化酶的影响

该文以蓝果忍冬品种蓝精灵为试材,研究微环境气调对蓝果忍冬在低温贮藏期间果实感官品质、生理指标、营养成分、抗氧化酶活性的影响.实验结果表明,与对照相比,mMA能够有效维持蓝果忍冬果实自身的感官品质和营养成分,到贮藏期末期(60 d)时,mMA处理后果实中的抗坏血酸、花色苷,黄酮、总酚含量分别为123.09 mg/10...     

1-MCP早酥梨常温贮藏期间果皮黄化、呼吸强度和品质的影响

研究了1-甲基环丙烯(1-MCP)对早酥梨在常温(23±1℃)贮藏期间果皮黄化、呼吸强度以及果实品质变化的影响.结果表明,在常温(23±1℃)条件下,1-MCP处理显著抑制了果皮黄化和叶绿素含量的下降,较好地保持了果皮绿色,并且明显降低了呼吸强度,推迟了呼吸高峰的到来,降低了呼吸峰值.经过1-MCP处理的早酥梨,其硬度和可溶性固形物含量的下降速度明显减慢,固酸比的上升速度受到抑制.采后1-MCP处理明显延缓了早酥梨的后熟衰老,三个浓度中以1.0μL/L的1-MCP处理效果最好.