低压静电场辅助冷冻对竹笋品质的影响

为研究低压静电场辅助冷冻对竹笋冻结特性的影响，以冻结曲线、硬度、水分损失率、水分迁移、冰晶形态和组织微观结构为指标，探究低压静电场辅助冷冻（－35 ℃）和普通冷冻（－35 ℃）条件下竹笋品质的变化规律。结果表明：低压静电场辅助冷冻提高了冻结效率，改变了冰晶形态及分布，减轻了组织微观结构破损程度，改善了解冻汁液流失情况。与静电板间距10、20、30、40 cm处的冷冻竹笋解冻后水分损失率分别为14.16%、12.58%、9.73%、10.44%，显著低于对照组（21.01%）（P＜0.05），硬度分别为461.19、507.48、496.65 g和455.31 g，显著高于对照组（350.70 g）（P＜0.05）。低场核磁共振分析结果表明，在低压静电场辅助冷冻下竹笋解冻后汁液流失减少，扫描电子显微镜观察结果显示，竹笋纤维排列整齐，组织微观结构保持较好。低压静电场辅助冷冻可有效改善竹笋品质，可为利用低压静电场进行果蔬的冷冻贮藏和冷链运输提供参考。

Effect of Low Voltage Electrostatic Field-Assisted Freezing on the Quality of Bamboo Shoots

In order to study the effect of low voltage electrostatic field (LVEF)-assisted freezing on the freezing characteristics of bamboo shoots, freezing curves, texture, drip loss, water migration, ice crystal morphology and microstructure were used as indicators to evaluate the effect of LVEF-assisted freezing (–35 ℃) and regular freezing (–35 ℃) on the quality characteristics of frozen bamboo shoots. The results showed that LVEF-assisted freezing improved the freezing efficiency, changed the shape and distribution of ice crystals, and reduced the degree of microstructural damage and thawing loss of bamboo shoots. The drip loss of bamboo shoot samples subjected to LVEF treatment at 10, 20, 30 and 40 cm away from the electrostatic field generating plate were 14.16%, 12.58%, 9.73% and 10.44%, respectively and were significantly lower than 21.01% for the control group (P < 0.05), and the hardness values were 461.19, 507.48, 496.65 and 455.31 g, respectively and were significantly higher than 350.70 g for the control group (P < 0.05). Low-field nuclear magnetic resonance (LF-NMR) spectroscopy indicated that the thawing loss of bamboo shoots was reduced under LVEF. Scanning electron microscope (SEM) observation showed that the bamboo shoot fibers were arranged neatly and the microstructure of bamboo shoots was well maintained. In summary, LVEF-assisted freezing can effectively improve the quality of bamboo shoots, which will provide guidance for utilizing LVEF in the frozen storage and cold chain transportation of fruits and vegetables.