超声波处理结合纳米包装对鲜切生菜品质的影响

运用超声波清洗结合纳米包装技术对鲜切生菜进行保鲜贮藏，通过测定贮藏期间生菜的主要品质、生理和微生物指标以探讨其保鲜作用。结果表明，纳米包装在抑制生菜质量损失，保持叶绿素、还原糖、VC含量方面效果都要优于超声波作用，而超声波处理（240 W、10 min、20 ℃）在抑制生菜酶活和表面微生物上的作用要较纳米包装好；超声波处理结合纳米包装对生菜的保鲜效果最佳，能够降低质量损失率，较好地保叶绿素和还原糖含量，控制微生物的生长，抑制多酚氧化酶和过氧化物酶活性，从而延缓衰老和褐变。经感官评定发现，超声波处理结合纳米包装的鲜切生菜在（4±0.5）℃、相对湿度85%～95%的贮藏环境中贮藏15 d后仍有商品价值。

Effect of Ultrasonic Treatment Combined with Nano-Packaging on the Quality of Fresh-Cut Lettuce

The effect of ultrasonic treatment combined with nano-packaging as a novel preservation method for fresh-cut
lettuce was studied by measuring quality, physiological and microbial indexes of the treated lettuce during storage. Results
indicated that nano-packaging treatment was more effective in inhibiting the increase of weight loss rate and maintaining
the contents of chlorophyll, vitamin C and sugar than ultrasonic treatment. However, compared with nano-packaging,
ultrasonic treatment showed a better effect on the inhibition of POD and PPO activities and microbial growth. The best
preservation effect was achieved when nano-packaging was combined with 240 W ultrasonic treatment for 10 min at 20 ℃.
This combinatorial treatment reduced the loss of weight, maintained chlorophyll and sugar contents and controlled bacterial
growth. Moreover, the activities of PPO and POD were repressed, and the senescence and browning were delayed. Sensory
evaluation showed that lettuce treated with ultrasound and nano-packaging still had commercial value after 15 days of
storage at (4 ± 0.5) ℃ and a relative humidity of 85%–95%.