该文研究了超高压处理对砀山梨汁中过氧化物酶活性的影响.试验压力为0.1～500 MPa,温度为20～60℃.此外,考察了不同pH值(3～7)和保压时间(2～34 min)超高压处理对酶活性的影响.试验结果表明:在处理温度为50℃、保压时间为10 min和梨汁pH 5的条件下,300 MPa以下压力范围内高压处理酶被激活,其活性增加;大于300 MPa时酶的活性随压力增大而下降.高压处理时,温度低于40℃对酶的活性影响不大;有效影响高压处理的最小温度为40℃.保压时间超过10 min后时间延长对酶的活性影响甚微;认为保压时间不是影响酶活性的主要因素.pH小于5或大于6时酶的活性降低;当pH值为6时,梨汁中过氧化物酶最耐压.处理条件为500 MPa、50℃、pH 3和保压10 min时可以较好地钝化过氧化物酶活性,是综合效果较佳的砀山梨汁超高压处理工艺.
A study was carried out about the effect of high hydrostatic pressure treatment (0.1～500 MPa) under temperature 20～60℃ and dwell time 2~34 min on peroxidase (POD) activity of Chinese Dangshan pear juice with different pH (3.0～7.0). Results showed that the peroxidase was activated when the high pressure treatment of the pear juice was carried out under the temperature 50℃, the dwell time 10 min, the pH 5 and the pressure less than 300 MPa; while its activity elevated. On the contrary, when the pressure more than 300 MPa, the peroxidase activity increased with the increase of pressure. High pressure treatment under temperature of less than 40℃ did not remarkably affect the peroxidase activity; contrarily, under temperature of more than 40℃ it was affected remarkbly. The peroxidase residual activity did not remarkably be decreased when the dwell time was longer than 10 min in the high pressure treatment. The peroxidase is the most pressure-resistant under pH 6. High pressure treatment at 500 MPa under 50℃, pH 3 for 10 min has a good ability to inactivate peroxides in the experimental conditions, and it is the optimal high pressure procedure to Chinese Dongshan pear juice.
Transactions of the Chinese Society of Agricultural Engineering