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.     

高压静电场处理对几种呼吸跃变型果实呼吸强度的影响

以苹果等几种呼吸跃变型果实为试材,研究了100kV/m的高压静电场每天处理2h对其呼吸强度变化规律的影响并与相同条件下的对照果进行了比较,发现高压静电场处理能够有效地降低这几种果实呼吸强度的最大值,并不影响它们呼吸高峰出现的时间。     

Effect of high-voltage electrostatic field pretreatment on the antioxidant system in stored green mature tomatoes

BACKGROUND: High‐voltage electrostatic field (HVEF), as a feasible and non‐chemical technique, applied to food preservation is a new area of study. Our previous research suggested HVEF could maintain the quality of tomato in storage. The present article intensively investigated the effect of HVEF pretreatment on antioxidant system of green mature tomato in storage. RESULTS: Green mature tomatoes were exposed to negative (or positive) HVEF for 2 h at 20 °C and then stored for 24 days at 13 ± 1 °C, 85–90% relative humidity. The results indicated HVEF significantly reduced contents of O₂^? and H₂O₂ of tomato fruits during storage compared to the control. HVEF treatment also enhanced the activities of antioxidant enzymes including catalase, superoxide dismutase, ascorbate peroxidase and peroxidase. The contents of non‐enzyme antioxidant components including reduced glutathione, phenols and ascorbic acid also were increased by HVEF treatment. However, HVEF treatment did not increase the content of lycopene in tomato fruit. CONCLUSION: HVEF treatment could promote the antioxidant capacity of tomato fruits in storage. Further research is be highly recommended to understand the mechanisms improving the antioxidant capacity of tomato fruits by HVEF. Copyright © 2011 Society of Chemical Industry     

高压电场技术在食品杀菌中的应用研究进展

高压电场技术是极具有工业化应用前景的低温杀菌技术之一，由于其杀菌效率高、能耗小、无污染且对食品品质影响小，因而在未来食品杀菌领域具有广阔的发展前景。本文对常见的两种高压电场类型，高压静电场和高压脉冲电场的装置特点、杀菌相关电场参数以及杀菌机理进行了介绍，综述了二者在固体和液体食品杀菌中的应用研究进展，介绍了国内外对传统电场设备暴露的缺点的改进情况，并总结了高压电场与其他杀菌技术的联用，最后展望了高压电场技术在未来的发展前景。     

高压静电场结合制冷对刀额新对虾的保鲜作用

为探究高压静电场技术对刀额新对虾冷藏期间品质的影响，本研究在实验条件下选取三种高压（8 kV、12 kV、16 kV）在4 ℃低温贮藏条件下连续处理刀额新对虾，于贮藏第0 d、2 d、4 d和6 d测定其色差、质构、pH值、TVB-N值、TBA值和菌落总数等鲜度指标的变化。研究结果表明，高压静电场处理组样品表现出更好的颜色和质构特性，有效延缓硬度的降低。虾肉中微生物生长得到有效抑制，与对照组相比，HVEF处理可以减少0.51~1.03 log?cfu/g。对照组第4 d时TVB-N值超过30 mg/100 g，而16 kV电场组在第6 d时仅为24.67 mg/100 g，这表明高压静电场处理能够有效延缓蛋白质的降解。电场处理组样品的其他鲜度指标如pH值和TBA值在整个贮藏期内均显著低于对照组（p<0.05）。此外，随着电压值的增加，保鲜效果越好。综合比较分析，高压静电场对刀额新对虾有较好的保鲜作用，高压静电场结合冷藏能够延长刀额新对虾货架期2 d以上。本研究为静电场保鲜刀额新对虾及静电场保鲜设备的改进提供科学依据。     

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.     

Effect of selenium fortification during sprouting of peanut seeds receiving HVEF and selenium soaking combination on yield,selenium and resveratrol contents,anti-oxidative properties,and microbial control

Selenium (Se) is essential for human nutrition as it involves many biological functions. In this study, three seed treatments (water soaking, high-voltage electric field (HVEF), HVEF and water soaking), and two Se fortification treatments (Se soaking with Se fortification during sprouting and HVEF plus Se soaking with Se fortification during sprouting) were used to examine their effects on peanut seed germination, Se contents and microbial loads on 8-days-old peanut sprouts. The results indicated that the best treatment for enhancing germination (99.6%), increasing the sprout's total Se and resveratrol contents (61.32 and 46.32 μg g ⁻¹ , respectively) was HVEF plus Se soaking in combination with Se fortification. It also reduced the microbial loads to <3 log CFU g⁻¹ FW on the resultant 8-days-old peanut sprouts. Thus, the treatment of HVEF and Se soaking combination with Se fortification can be used to produce Se-fortified peanut sprouts with improved nutritional quality and microbial control.     

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。     

高压静电场（HVEF）联合冰温处理对莲藕贮藏品质变化的影响

以新鲜莲藕为试材,研究了高压静电场联合冰温技术对莲藕贮藏期间褐变和贮藏品质的影响。结果表明,高压静电场处理联合冰温贮藏对莲藕贮藏期间的褐变有抑制作用,贮藏28 d后褐变度仅为7(A410×10),腐烂指数为15%,均明显低于对照。同时产品保持较高的硬度和可溶性固形物含量,贮藏28 d后硬度约保持为3 kgf/cm2,可溶性固形物约为4%。并且贮藏28 d后,呼吸强度为50 mg/kg.h,乙醇含量为18 nmol/g,细菌总数为5 CFU/g,均明显低于对照,说明该处理可以有效地抑制呼吸强度和乙醇的积累,控制微生物数量的增加,减少腐烂发生。     

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.