【作者】 刘进杰；

【导师】 陈从贵；

【作者基本信息】 合肥工业大学 ， 农产品加工及贮藏工程， 2003， 硕士

【摘要】 食品高静压技术是目前研究的热点技术，既能有效灭菌，又能较好的保留营养成分及色、香、味等。本研究以食品高压技术产业化为目标，采用中温与瞬变高压协同加工方法，在低于100MPa压力的范围内，研究了工作压力、进料温度、pH值和处理时间等因素对液态食品微生物、多酚氧化酶(PPO)、过氧化物酶(POD)及抗坏血酸(Vc)的影响，并探索了评价指标与各影响因素间的相互关系。 研究结果表明，中温条件下，引入瞬变高压，可明显提高细菌的致死速率。进料温度35℃时，10～80MPa压力范围内，20MPa的杀菌效果最好；20MPa瞬变压力下，进料温度为35～55℃内，55℃时的杀菌效果最好；总体上，处理时间越长，杀菌效果越高，但50MPa处理2min后，杀菌效果趋于平稳；pH值4.0时杀菌效果最佳。中温协同瞬变压力处理可激活或钝化PPO，进料温度为35℃时，10～80MPa压力范围内，20MPa和50MPa的压力可激活PPO活性，而其它压力可钝化PPO活性；20MPa压力下，进料温度35～55℃内，35℃时的PPO钝化能力最大；处理时间延续，20MPa和50MPa作用下，PPO先激活后失活，而80MPa时PPO活性逐渐降低；pH3.0时钝化PPO能力最强。采用中温协同瞬变压力处理也可使POD钝化或激活，进料温度为35℃时，10～40MPa的压力处理可激活POD，而50～80MPa的压力可钝化POD；20MPa压力下，进料温度35～55℃内，55℃时的POD钝化能力最强；处理时间延长，POD活性先升后降；酸性越强，钝化POD效果越好。协同处理对抗坏血酸的影响较小，随压力的增大，进料温度的升高，处理时间的延续，pH值的降低，Vc保存率均会降低。正交试验表明最佳灭酶条件是工作压力80MPa、进料温度35℃、pH值4.0、处理时间8min。更多还原

【Abstract】 High hydrostatic pressure (HHP), the focus in food processing field, can not only kill food-borne microorganisms, but bring less detriment to food compounds such as nutrients, pigments, and flavoring agents, etc.. The processing method of combined medium temperature and high-pressure jet was studied to make HHP industrialization. The effects of pressure, material temperature, pH value and treatment time on the bacteria, polyphenoloxidase (PPO), peroxidase (POD) and ascorbic acid (Vc) were studied respectively. The relationship between the estimation index and the influence factors was discussed, too.Results showed that combined medium temperature and high-pressure jet could evidently promote sterilization effect. With the material temperature of 35℃ and the pressure of 10-80MPa, the death rate arrived the highest at 20MPa. Given the pressure of 20MPa combined with the temperature of 35-55℃, the fatality result at 55℃ was the best. In short, the longer the treatment time, the less the viable bacteria. However, treated for 2min at 50MPa,the sterilization became steady. The survivor of bacteria was the least at pH4.0. PPO can be affected by the combination treatment. At 35℃ and 10-80MPa, the pressure of both 20MPa and 50MPa could activate PPO, while other pressures inactivated it. At 20MPa, the inactivation of PPO was the most striking at 35℃. As time went on, the pressure of 20MPa and 50MPa made PPO activate at first and inactivate later. However, PPO was gradually inactivated at 80MPa. PPO was inactivated most evidently at pH3.0. Combination treatment also affected POD activity. The pressure of 10-40MPa could activate POD, while the pressure of 50~80MPa inactivated it. At 20MPa, the inactivation of POD at 55℃ was the most marked. When the treatment time extended, POD activity was first rise and then drop. The lower the pH value, the stronger the inactivation of POD. The combination treatment could less affect ascorbic acid. The surplus rate of Vc would lower in respond to the increase of pressure, temperature, the treatment time and the acidity. By means of composite experiments, an optimum condition turned out to be the combination of the pressure of 80MPa, the material temperature of 35℃, pH4.0 and the treatment time of 8min.更多还原