超高压处理对荔枝果肉中两种酶和可溶性蛋白的影响

 为了研究超高压处理对荔枝果肉中过氧化物酶（POD）、果胶甲基酯酶（PME）及可溶性蛋白含量的影响，将荔枝（“淮枝”品种）果肉在100~400 MPa压力、10 ℃温度条件下处理30 min，采用分光光度法测定果肉中POD、PME的活性，用天然凝胶电泳法以及活性染色法测定POD、PME同工酶的变化，用SDS凝胶电泳法测定果肉中可溶性蛋白含量。结果表明：100~200 MPa超高压处理使荔枝果肉中POD活性上升且出现新的同工酶，300~400 MPa超高压处理则使其活性降低且新出现的同工酶消失；100 MPa压力处理使荔枝果肉中PME活性上升且出现新的同工酶，200~400 MPa超高压处理则使其活性降低且新出现的同工酶消失；100 MPa超高压处理使荔枝果肉中可溶性蛋白含量有所增加，而在200~400 MPa压力处理下其含量持续下降。

Influence of Ultra High Pressure on Peroxidase Pectin Methyl Esterase and Soluble Protein in Litchi Fruit

In order to investigate the effects of ultra high pressure (UHP) on the content of soluble protein, peroxidase (POD) and pectinmethylesterase (PME) in litchi fruit, the pulp of litchi (Litchi chinensis Sonn cv. Huaizhi) was subjected to UHP treatment (100~400 MPa for 30 min at 10 ℃). The activities of POD and PME were detected by spectrophotometry, the isoenzymes of POD and PME were detected by native-PAGE and active staining. The content of soluble protein was detected by SDS-PAGE. Results showed that the POD activity raised and the new isoenzyme appeared when a treatment of 100~200 MPa was applied, the treatment of pressure 300~400 MPa made the POD activity decrease and the new isoenzyme disappear. The PME activity ascended and the new isoenzyme of PME appeared at 100 MPa; when the treatment of 200~400 MPa was applied the PME activity lowered and the new isoenzyme disappeared. The content of soluble protein had a little increase at 100 MPa, but continue to declined at 200~400 MPa.