壳聚糖涂膜藕带褐变的隔氧控制

Effect of Chitosan Coating Combined with Oxygen-Free Packaging on Enzymatic Browning during Cold Storage of Young Lotus Rhizomes

藕带在贮藏过程中极易发生酶促褐变,对氧气的敏感度很高。以藕带为实验材料,经过壳聚糖涂膜后的藕带,分别用充氮和真空包装隔氧,然后低温贮藏,观察测定藕带褐变情况。结果表明:经预处理的藕带,用2g/100mL壳聚糖涂膜,保鲜膜包裹后真空包装,置于0～5℃条件环境中冷藏,藕带品质保持良好,至少长达2个月;贮藏过程中藕带褐变是品质控制的关键因素;贮藏期间,藕带总酚含量下降,多酚氧化酶(PPO)活性下降但没有完全失活;藕带相对电导率上升,细胞膜透性增强,与褐变具有一定相关性。涂膜藕带真空包装比充氮贮藏具有更好的效果。

Young rhizomes of lotus are extremely vulnerable to enzymatic browning and highly sensitive to oxygen. Lotus rhizomes coated with chitosan were packaged in vacuum or nitrogen gas under oxygen-free conditions and then stored at low temperatures. The degree of browning in lotus rhizomes was observed during the storage. The quality of samples subjected to pretreatment, 2 g/100 mL chitosan coating, cling film wrapping and vacuum packaging remained good for at least 2 months at 0–5 ℃. Enzymatic browning was a critical determinant for quality control of lotus rhizomes during storage. Furthermore, the content of total phenolic compounds declined, PPO activity was inhibited but not completely inactivated, relative conductivity rose, and cell membrane permeability was enhanced. All these indicators were correlated with enzymatic browning. Vacuum packaging was more effective than nitrogen gas packaging.