Kim M J, Oh J M, Cheon S H, Cheong T K, Lee S H, Choi E O, Lee H G, Park C S, Park K H
Department of Food Science and Technology and Research Center for New Bio-Materials in Agriculture, School of Agricultural Biotechnology, Seoul National University, Suwon 441-744, South Korea.
J Agric Food Chem. 2001 May;49(5):2241-8. doi: 10.1021/jf001379b.
Lipid-acyl hydrolases (LAHases) play significant roles in lipid degradation during the storage of vegetables. In particular, spinach contains a large portion of galactolipids (59.5%) and phospholipids (22.4%) among its fat-soluble components, which are used as substrates for LAHases. Thermal inactivation of various LAHases, including phospholipases A, C, and D, phosphatase, and galactolipase, from spinach and carrot was investigated to optimize the blanching process prior to the frozen storage of vegetables. Thermostability of phospholipase C or galactolipase was greatest among the LAHases from both spinach and carrot. Galactolipase from spinach exhibited a D value of 3.39 x 10(2) s at 80 degrees C and a z value of 8.21 degrees C, whereas phospholipase C from spinach showed D(80) of 1.72 x 10(2) s with a z value of 9.26 degrees C. In the case of LAHases from carrot, the D(65) and z values of galactolipase were 6.66 x 10(2) s and 8.69 degrees C, respectively, whereas phospholipase C displayed D(85) of 3.12 x 10(2) s and a z value of 15.8 degrees C. Highly active and thermostable galactolipase and phospholipase C in spinach and carrot made it possible for them to be used as indicator enzymes for the determination of quality deterioration of the stored vegetables.
脂酰水解酶（LAHases）在蔬菜储存过程中的脂质降解中发挥着重要作用。特别是，菠菜的脂溶性成分中含有很大一部分半乳糖脂（59.5%）和磷脂（22.4%），它们可作为LAHases的底物。研究了菠菜和胡萝卜中包括磷脂酶A、C和D、磷酸酶以及半乳糖脂酶在内的各种LAHases的热失活情况，以优化蔬菜冷冻储存前的热烫工艺。菠菜和胡萝卜中的LAHases中，磷脂酶C或半乳糖脂酶的热稳定性最高。菠菜中的半乳糖脂酶在80℃时的D值为3.39×10²秒，z值为8.21℃，而菠菜中的磷脂酶C在80℃时的D值为1.72×10²秒，z值为9.26℃。就胡萝卜中的LAHases而言，半乳糖脂酶的D(65)值和z值分别为6.66×10²秒和8.69℃，而磷脂酶C的D(85)值为3.12×10²秒，z值为15.8℃。菠菜和胡萝卜中高活性且热稳定的半乳糖脂酶和磷脂酶C使其有可能被用作测定储存蔬菜质量劣化的指示酶。
