果蔬冷冻新技术的研究进展

A Review of Novel Freezing Technologies on Fruits and Vegetables

概述了几种果蔬冷冻新技术,即高压冷冻、超声波联合冷冻、电磁场辅助冷冻(磁场辅助冷冻和脉冲电场冷冻处理),这些技术主要通过缩短冷冻时间(6%~24%)、形成较小的冰晶(直径≤80μm)以提升冷冻产品品质。高压冷冻形成冰晶具有瞬时性,能应用于体积较大的水果,但不适合质地过软的果蔬;超声波冷冻通过超声波空穴效应,形成更小的冰晶并能一定程度灭酶,缺点是冷冻过程需要包装以隔绝冷冻液;磁场辅助冷冻是最先应用于生产中(日本CAS冷冻设备),能缩短果蔬冷冻相变时间;脉冲电场冷冻虽能显著缩短冷冻时间,但易造成细胞膜穿孔,需要配合冷冻保护剂和组织改进剂。因此,应该根据果蔬体积、质地等因素选择合适的冷冻新技术,以提高果蔬冷冻品质。

This article reviewed the novel freezing technologies on fruit and vegetable,including pressure-assisted freezing,ultrasound-assisted freezing,electrically-magnetically disturbed Freezing(magnetic field-assisted freezing and pulsed electric field-assisted Freezing).These novel technologies improve the quality of frozen foods by shortening the freezing time(6%~24%)and forming smaller ice crystals(diameter≤80μm).The formation of ice crystals by high-pressure freezing was instantaneous,so it can be used in large volume fruits,but not suitable for fruit and vegetable with soft texture.Ultrasound-assisted Freezing technology can form smaller ice crystals and deactivate enzymes to a certain extent by the effect of ultrasonic cavitation,but the fruits and vegetables need packaging to isolate the freezing liquid.Magnetic field-assisted freezing technology was first used in industrial equipment(CAS refrigeration equipment in Japan),which can shorten the freezing phase transition time of fruit and vegetable.Pulsed electric field-assisted freezing can significantly shorten the freezing time,but it is easy to pierce cell membrane,so it requires cryoprotectants and tissue improvers.Therefore,it should choose suitable novel freezing technologies according to the volume and texture of fruit and vegetable,so that improve the quality of freezing fruits and vegetables.