交变磁场抑制葡萄冻害机理分析及试验研究

Analysis and experimental study on the inhibition mechanism of grape freezing injury by alternating magnetic field

冻害是影响果蔬品质,造成经济损失的重要因素之一。鉴于目前化学及生物处理存在食品安全隐患,为此开发1种抑制冻害的绿色安全高效的物理处理方法具有重要科学意义。本课题组基于电磁场的生物效应及热效应研制了1种低温电磁保鲜系统,开展了葡萄贮藏期间(T=(-2.5±0.2)℃,RH=(90±3.0)%)交变磁场连续(AMCT)与间歇处理(AMIT)影响冻害的对比试验研究。结果表明,适宜强度的磁场处理可以有效降低葡萄组织液的相变潜热和结晶温度,其中经磁场处理(B=40 Gs,f=80 Hz)后的葡萄组织液过冷度可提高4.8℃,有利于降低冰温贮藏下葡萄的冻害几率。此外,交变磁场间歇处理对葡萄的影响更加明显,其中AMIT组的色差、PPO活性和MDA含量分别为对照组的83.1%、88.4%和88.2%。综上,交变磁场抑制果蔬冻害效果显著,为探索多物理场耦合处理抑制果蔬冻害开辟了新方向。

Freezing injury(FI) is one of the important factors affecting the quality of fruit and vegetable and causing economic loss. In view of the potential danger in food safety caused by chemical and biological treatment, it is of great scientific significance to develop a green, safe and efficient physical treatment method to inhibit FI. In this research, a low temperature electromagnetic fresh-keeping system was developed based on the biological and thermal effects of electromagnetic fields. A comparative experiment was conducted to study the effects of alternating magnetic field continuous treatment(AMCT) and alternating magnetic field intermittent treatment(AMIT) on FI during grape storage(T=(-2.5±0.2)℃,RH=(90±3.0)%). The results showed that the phase change latent heat and crystallization temperature of the grape tissue solution could be reduced effectively by the magnetic field treatment with appropriate strength, and the supercooling degree of the grape tissue solution could be increased by 4.8 ℃ after the magnetic field treatment(B=40 Gs, f=80 Hz), which was conducive to reducing the FI rate of grapes under the freezing temperature storage. In addition, AMIT had more obvious effects on grapes, in which the color difference, PPO activity and MDA content of AMIG group were 83.1%, 88.4% and 88.2%, respectively, as compared with those of the control group. In conclusion, alternating magnetic field has a significant effect on the inhibition of fruit and vegetable FI, which opens up a new research direction for exploring multi-physical field coupling treatment to inhibit fruit and vegetable FI.