【目的】以新鲜金佛山方竹(Chimonobambusa utilis)笋为原料,采用液氮速冻—真空包装—冻藏保鲜技术冻藏速冻方竹笋,考察贮藏过程中其硬度、色泽、营养品质和酶活的变化,旨在延长方竹笋的冻藏保鲜时间,为方竹笋液氮速冻的工业化生产与品质控制提供理论支撑。【方法】以带壳方竹笋为研究对象,经液氮速冻、真空包装得到速冻方竹笋,在0~180 d冻藏(-18 ℃)过程中,考察其硬度、色泽、蛋白质及氨基酸、粗纤维、总糖、脂肪、维生素C、硒等主要品质指标,分析贮藏时间对速冻方竹笋过氧化物酶(POD)、多酚氧化酶(PPO)、苯丙氨酸解氨酶(PAL)等酶活性的影响。【结果】冻藏时间的延长对方竹笋的硬度和色泽有一定影响,冻藏时间≥90 d时,速冻方竹笋的硬度有所增加,而速冻方竹笋的L^*、a^*、b^*值却均有所降低。随着贮藏时间的延长,水分、蛋白质、总氨基酸、总糖、维生素C含量逐渐降低,而粗纤维的含量却逐步增高,其含量均在冻藏90~180 d时趋于稳定,整个过程中,脂肪、硒和单宁含量基本稳定。在贮藏180 d时,水分、蛋白、粗纤维、总糖、脂肪、人体必需氨基酸、维生素C、硒的质量分数分别为91.24%、2.51%、2.82%、0.93%、0.27%、552.96×10^-3%、13.14×10^-3%、0.785×10^-6%,营养品质优良。在冻藏[0,90) d时,PAL、PPO、POD活性显著下降,在冻藏[90,180] d时,其活性较低且变化不大,对方竹笋的品质指标无显著影响。【结论】液氮速冻—真空包装—冻藏保鲜技术实现了金佛山方竹笋保鲜保质达6个月,是一种竹笋保鲜的可行方法。

【Objective】Fresh Chimonobambusa utilis shoots from Jinfoshan mountain were processed by the technique of liquid nitrogen quick-freezing-vacuum packing-frozen storage. The dynamics (hardness, color, nutritional quality and enzyme activity) during storage were investigated with the increasing the frozen storage time, and thus providing a theoretical support for the industrial production and quality control of fresh C. utilis shoots under the liquid nitrogen quick-frozen storage condition.【Method】C. utilis shoots with shells were used to produce quick-frozen bamboo shoots by the processes of liquid nitrogen quick-freezing and vacuum packaging. At a frozen storage process (-18℃, 0-180 d), the main quality indicators of the quick-frozen shoots were determined in terms of hardness, color, protein and amino acids, crude fiber, total sugar, fat, vitamin C, and selenium. The enzymatic activities (POD, PPO and PAL) of the quick-frozen shoots at different storage time were also analyzed. 【Result】The hardness and color of fresh C. utilis shoots under the liquid nitrogen quick-frozen storage condition were affected by the frozen storage time. When the frozen storage time was ≥90 d, the hardness increased slightly, while their L^*, a^* and b^* values decreased a little. With the increasement of storage time, the contents of water, protein, total amino acids, total sugar and vitamin C gradually decreased, while the content of crude fiber gradually increased. These contents tended to be stable at 90-180 d. The contents of fat, selenium and tannin were basically stable in the storage time. When the frozen storage time was at 180 d, the contents of water, protein, crude fiber, total sugar, fat, essential amino acid, vitamin C and selenium were respectively 91.24%, 2.51%, 2.82%, 0.93%, 0.27%, 552.96×10^-3%, 13.14×10^-3%, 0.785×10^-6%, with good quality. The activities of PAL, PPO and POD decreased significantly during 0-90 d, and they were stable at 90-180 d. The quality of C. utilis shoots was affected little by enzymatic activity at the storage time (90-180 d). 【Conclusion】 Finally, the liquid nitrogen quick-freezing-vacuum packing-frozen storage technology had achieved a preservation of 6 months for fresh C. utilis shoots under the liquid nitrogen quick-frozen storage condition. Thus, it is a feasible method for the preservation of fresh bamboo shoots.