Effects of high-voltage electrostatic fields on the quality of tilapia meat during refrigeration

Abstract: Fresh fish is typically brought to market refrigerated at approximately 4 °C, R‐storage. A storage method has been devised that combines refrigeration with a high‐voltage electrostatic field (100 kV/m; E‐storage). It was developed to improve the quality and prolong the shelf life of foods. This study investigated changes in the freshness of tilapia meat under E‐storage conditions. The total viable count of tilapia reached 10⁷ CFU/g on the 7th d of refrigeration in R‐storage. By the 6th d, K‐value had increased from 20% to 61.7% for E‐storage and to 94.7% for R‐storage. Volatile basic nitrogen had increased from 12.54 mg/100 g to about 24.34 and 25.03 mg/100 g for R‐ and E‐storage (on the 7th and 10th d), respectively. The sensory assessment also indicated that E‐storage yielded an improvement in quality over that of R‐storage. Practical application of the study model has the potential to prolong the freshness of fish.     

Effect of high-voltage electrostatic field on quality of carrot juice during refrigeration

In the present study, carrot juice was used as the experimental material and stored in a 100 kV/m high-voltage electrostatic field (HVEF; E-group) which was used as a freshness-retention system. The changes in the biological properties were investigated relative to those juices which were stored in a common refrigerator (R-group) and controlled at the same temperature (4 °C). The results showed that the extent of color difference (ΔE), amount of total phenolics, tannins, and total plate counts of carrot juice were increased during the storage period, whereas the turbidity and amount of total carotenoids decreased under all treatment conditions. These factors remained relatively constant during storage in the E-group, whereas a significant difference (p < 0.05) was observed in the R-group. The HVEF treatment yielded better physicochemical properties and prolonged the shelf-life of the carrot juice. The application of HVEF at low temperature has the potential of imparting freshness and a high nutritional value to the products.     

Keeping quality of tomato fruit by high electrostatic field pretreatment during storage

BACKGROUND: High electrostatic field, as a feasible and non‐chemical technique, applied to food preservation is a new area of study. The present article intensively investigated this new preservation method, together with its effects on post‐harvest physiology and quality of tomato. RESULTS: Green mature tomatoes were exposed to negative (or positive) high electrostatic field for 2 h at 20 °C and then stored for 30 days at 13 ± 1 °C, 85–90% RH. Our results indicated that negative high electrostatic field (?2 kV cm^?1) could delay the decline of firmness and the change in color, total soluble sugar and titratable acidity of tomato fruit during storage. The peak of respiration and ethylene production of tomato fruit during storage were delayed by negative high electrostatic field treatment for 6 days and 3 days, respectively. Increases of malondialdehyde content and electrical conductivity in tomato fruit were inhibited significantly by negative high electrostatic field treatment during storage (P < 0.05). CONCLUSION: A high electrostatic field of ? 2 kV cm^?1 can be used to keep the qualities and extend the shelf‐life of tomato fruit. Further research should be highly recommended to understand the mechanisms improving the storability of tomato fruit by negative high electrostatic field. Copyright © 2007 Society of Chemical Industry     

高压静电场对菜豆角冷害的影响

以菜豆角为试材,研究了场强为-100kV/m和100kV/m的高压静电场(HighVoltageElectrostaticField,HVEF)处理对菜豆角贮藏过程中冷害发生的影响。试验结果表明,在5℃下,不同场强方向高压静电场处理都能降低菜豆角的冷害指数和锈斑指数,表明高压静电场处理对菜豆角的冷害有明显的抑制作用。通过对高压静电场处理下菜豆角的细胞膜透性和膜脂过氧化作用的观测发现,冷害温度下高压静电场处理组菜豆角细胞膜透性及丙二醛(MDA)累积程度都有显著降低。说明高压静电场能抑制冷害的发生,其原因可能在于高压静电场处理能有效地保护细胞膜的结构,并减轻膜脂的过氧化程度。     

Effect of high voltage electrostatic field treatment on thawing characteristics and post-thawing quality of frozen pork tenderloin meat

The thawing characteristics and post-thawing quality of frozen pork treated with high voltage electrostatic fields (HVEF) were compared with those of an air-thawed control. A multiple points-to-plate electrode operating at voltages above 6 kV significantly shortened the thawing time. Under electrode voltages 4, 6, 8, and 10 kV, thawing times were 70, 52, 46, and 40 min respectively, versus 64 min in the control. HVEF treatment was particularly effective in the temperature range −5–0 °C. HVEF treatment reduced the total microbial counts in thawed frozen meat by 0.5–1 log CFU/g, without affecting meat quality. During five days of post-thawing storage, the volatile basic nitrogen (VBN) levels increased from 10.64 to 16.38 mg/100 g under 10 kV applied voltage, while the control VBNs increased from 10.66 to 19.87 mg/100 g. This suggests an application potential for HVEF treatment in the thawing and storage of frozen meat.     

高压静电场对糙米发芽的影响研究

研究了不同强度的高压静电场(100、200、300kV/m)分别处理不同的时间(1、5、10、15min)对糙米发芽的影响。通过测定糙米发芽率和发芽糙米中的α-淀粉酶活性、还原糖、游离氨基酸的含量发现高压静电场对糙米发芽能够产生一定的影响;总体而言,从本实验中可得出,当电场强度在200kV/m,处理时间在10min时,效果最好,结果表明,高压静电场处理对糙米发芽率和活力具有显著促进作用。     

高压静电场对酿酒酵母菌的作用研究

研究了高压静电场对酿酒酵母菌的作用,实验结果表明,高压静电场对酿酒酵母菌细胞的生长速率有影响。不同的电场强度、作用时间对细胞生长的速率有所不同。此外还分别从物理学、生物学的角度研究了高压静电场作用于酿酒酵母菌的微观机理。     

减压贮藏对番茄果实抗氧化物质和抗氧化酶的影响

为了研究不同减压处理对番茄果实后熟过程中抗氧化性的影响,以粉冠番茄为材料,研究了在43.6、73.0kPa和常压三个压力条件下,番茄中维生素C、番茄红素和谷胱甘肽含量,以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性变化规律。结果表明,减压贮藏显著推迟了番茄中维生素C含量的高峰,在一定程度上延迟了番茄红素和谷胱甘肽含量的高峰,并且压力越低效果越显著(p<0.05);在果实后熟过程中SOD、CAT活性逐渐下降,而减压处理可显著抑制SOD活性下降(p<0.05)。POD活性在贮藏期间呈现先降后升的趋势,减压处理可以有效地保持较高的抗氧化酶活性。结论:减压处理贮藏可以显著保护番茄果实中的抗氧化物质和抗氧化酶活性,而且一定范围内压力越低效果越好。      

高压静电场处理对香蕉果实成熟生理的影响

以香蕉果实为试验材料,在(20±1)℃试验冷库中贮藏21d,贮藏期间用－100kV/m和－200kV/m的高压静电场连续处理并测定果实的呼吸强度、乙烯释放量、硬度、果皮颜色变化以及果肉淀粉和可溶性糖含量的变化。结果表明：连续高压静电场处理可以使香蕉果实的呼吸跃变和乙烯释放高峰提前,淀粉转化为糖的速度快而且比对照早,果皮叶绿素含量明显低于对照,同时处理后的果肉硬度下降,低于对照;并且－200kV/m处理组的效果要优于－100kV/m处理组。说明高压静电场连续处理促进了香蕉果实的成熟,尤以－200kV/m处理组比对照提前成熟4d。     

高压电场运用于加速食品解冻的研究

在综合论述常用解冻方法优缺点的基础上,提出一种新型的低温解冻技术——高压静电场解冻,介绍了这种技术的国内外发展现状,并且从水的角度初步探讨了解冻机理。     

静电场对干式成熟牛肉品质的影响

为研究高压静电场(High voltage electrostatic field,HVEF)对干式成熟牛肉品质的影响,实验通过对比测定施加2.0kV、3.0kV HVEF电压条件(试验组,成熟温度为0-4℃)及未施加HVEF(对照组,成熟温度为0-4℃)的牛肉背最长肌品质指标变化情况,探究HVEF对干式成熟牛肉品质的影响。结果表明,2.0kV、3.0kV高压静电场处理的牛肉剪切力在成熟第7d时已经接近可接受范围,分别为4.65kg和4.50kg,显著(P<0.05)低于对照组;高压静电场处理对牛肉干式成熟过程中保水性也具有显著影响(P<0.05),在成熟第14d时,2.0kV与3.0kV高压静电场处理组的蒸煮损失比对照组分别降低了5.13%、6.03%;在整个成熟过程中,试验组的硬度值均显著(P<0.05)低于对照组;随着成熟时间延长,试验组的肌原纤维小片化指数值(Myofibril Fragmentation Index,MFI)显著(P<0.05)高于对照组。综上,HVEF条件下干式成熟处理提高了牛肉的嫩度以及保水性,有助于提高干式成熟期间牛肉的品质,加快成熟过程。     

高压静电场解冻技术在肉类及肉制品中的应用

冷冻肉类及其制品的品质与解冻过程密不可分,选择合适的解冻技术至关重要。高压静电解冻技术具有解冻损失小、速率快等特点。该文综述了高压静电场的解冻机理及特点,对其应用于肉类及肉制品时对持水性、肌肉结构、颜色、解冻速率、贮藏时间等方面的影响做出了归纳,并展望了高压静电场解冻技术的发展前景,为今后其在肉及肉制品中的应用提供理论参考。     

芒刺高压静电场处理对大肠杆菌微生活环境的影响

采用直流芒刺高压静电场对食品中主要致病菌大肠杆菌的菌液进行处理,测定了电导率、pH、温度变化,以及大肠杆菌细胞的蛋白质泄露和核酸溢出的情况,并根据大肠杆菌生活微环境的变化对致死机理做了初步探讨。     

一氧化氮对绿熟和粉红期番茄采后抗氧化相关酶的影响

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高压静电场对桔青霉菌的作用效果与机理

利用自制高压静电场装置,对桔青霉菌进行不同场强度、时间及温度的处理来考察高压静电场对其孢子萌发率的作用效果;用典型作用参数处理观察青霉菌芽管长度、接种于健果上的菌斑大小及孢子形态来进一步验证对萌发率作用结果及作用机理的探讨。结果表明,高压静电场对青霉菌孢子的萌发具有促进和抑制两种完全不同的作用。场强小于40000V/m和处理时间小于20min能促进孢子萌发,场强大于62000V/m和处理时间超过60min能抑制孢子萌发,中间剂量的处理效果依据不同的处理而有所变化。温度对电场处理效果有着显著的影响,当温度升高到50℃,高剂量的场强处理可以完全抑制青霉菌孢子萌发。高压静电场对青霉菌的芽管长度、桔果上的菌斑大小的作用有着相似的结果。62000V/m、60min的处理使青霉菌的孢子形态结构受损,导致其孢子失去萌发能力。结果表明高压静电场为柑橘类的果蔬保鲜提供了一条物理处理新途径。     

高压脉冲电场杀菌系统中高压脉冲发生器研究进展

文章综述高压脉冲发生器的设计原理,分析国内外高压脉冲发生器的研究进展及其优缺点,并讨论系统设计的要点以及应用现状与展望。     

热激处理对鲜切甜椒活性氧代谢及贮藏品质的影响

为探讨热激处理鲜切甜椒的保鲜作用,对鲜切甜椒进行热水45、50、55℃分别浸泡10、4、1min处理后,于8℃冷藏期间分析了活性氧水平、抗氧化酶活性及品质指标。热激处理50℃4min和55℃1min,可抑制超氧阴离子（O-2）产生,减少过氧化氢（H2O2）含量,诱导提高超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性,抑制过氧化物酶（POD）活性,同时可以抑制丙二醛（MDA）积累,有效保持鲜切甜椒重量、叶绿素及可溶性蛋白质含量,55℃1min处理效果好于50℃4min处理。表明适宜的热激处理可通过调节活性氧代谢保持鲜切甜椒冷藏品质。      

高压静电场解冻技术在食品中的研究进展

随着冷冻食品消费量的不断增加,快速有效的解冻方式也日益受到重视,其中高压静电解冻技术由于其解冻速率快,时间短,营养损失少,设备简单易操作等独特优势在冷冻行业得到快速发展与应用。本文对高压静电场解冻技术的解冻机理以及优缺点进行了分析,介绍了国内外高压静电场解冻技术在果蔬类、冻肉类、水产类及其他食品的研究现状,并对高压静电场解冻技术的发展前景进行展望。      

Effect of Thawing and Cold Storage on Frozen Chicken Thigh Meat Quality by High-Voltage Electrostatic Field

ABSTRACT: One of the most popular issues in electrostatic biology is the effects of a high-voltage electrostatic field (HVEF) on the thawing of chicken thigh meat. In this study, chicken thigh meat was treated with HVEF (E-group), and compared to samples stored in a common refrigerator (R-group), to investigate how HVEF affects chicken thigh meat quality after thawing at low temperature storage (−3 and 4 °C). The results showed that there were no significant differences in biochemical and microorganism indices at −3 °C. However, the HVEF can significantly shorten thawing time for frozen chicken thigh meat at −3 °C. After thawing chicken thigh meat and storing at 4 °C, the total viable counts reached the Intl. Commission on Microbiological Specification for Foods limit of 10⁷ CFU/g on the 6 and 8 d for the R- and E-group, respectively. On the 8th d, the volatile basic nitrogen had increased from 11.24 mg/100 g to 21.9 mg/100 g for the E-group and 39.9 mg/100 g for the R-group, respectively. The biochemical and microorganism indices also indicated that the E-group treatment yielded better results on thawing than the R-group treatment. The application of this model has the potential to keep products fresh.