不同贮藏条件下竹笋苯丙氨酸解氨酶的活性变化

对不同贮藏条件下2种竹笋(毛笋和雷笋)体内苯丙氨酸解氨酶(PAL)的活性变化以及这些变化与竹笋褐变之间的关系进行了研究．结果表明，竹笋的褐变与其PAL活性密切相关，PAL活性越高，越容易发生褐变，竹笋PAL以基底部为最高，其次为中部，顶尖部最小，竹笋PAL活性受贮藏温度和状态的影响，低温(3～5℃)状态的酶活低于高温(18～24℃)状态，剥壳状态的酶活高于带壳状态．而在其它条件相同时，雷笋的PAL活性明显高于毛笋，在3～5℃冷藏时，带壳雷笋和毛笋的PAL活性均会在2d后有所下降，然后在11d时出现一个酶活高峰．

Variation in Phenylalanine Ammonia-Lyase Activity of Bamboo Shoots Under Different Storage Conditions

Under different storage conditions, the phenylalanine ammonia-lyase(PAL) activity of two strains of bamboo shoots (shoot of Phyllostachys pubescens and shoot of Phyllostachys praecoxf) and the relation between these changes and their browning were studied. The results showes that significant correlation exists between browning of bamboo shoots and their PAL activity, that is, the higher the PAL activity of bamboo shoots, the faster browning. PAL activity of bamboo shoots is the highest in the basal, then in the central section and the least in the apical section. To the same strains of bamboo shoot, their PAL activity is higher during storage at ambient temperature (18～24℃) than at low temperature(3～5 ), and higher without coats than with coats. The PAL activity of the bamboo shoots of Phyllostachys praecoxfis obviously higher than of Phyllostachys pubescen under the same storage temperature and state. In the both of bamboo shoots with coats, the PAL activity decreased after 2 days, then after 11 days they increased rapidly again at low temperature(3～5 ℃).