高压处理对鲜榨苹果汁品质的影响

The Effect of High Pressure on the Quality of Fresh Apple Juice

为探讨高压对鲜榨苹果汁品质的影响,对鲜榨苹果汁进行了100～800MPa处理及40～60℃协同500MPa处理,并采用HPLC等方法检测了苹果汁中酚类含量等品质指标。果汁中还原型VC的保留率随着处理压力的增大先降后升。200MPa处理后,果汁中酚类物质含量没有显著变化。400MPa处理后,果汁中酚类物质相比处理前的有所减少,差异显著(P<0.05)。600MPa处理后,各种酚类物质略有减少。800MPa时,各种酚类物质的含量增加。200～600MPa压力处理后果汁的L值降低,颜色变暗,其中400MPa处理颜色变化(△E)最大。当压力升高到300MPa时未检出霉菌和酵母菌,压力升高到400MPa时未检出细菌。果汁经高压处理后浊度降低,可溶性固形物含量和pH值没有显著变化(P>0.05)。50℃和60℃协同500MPa处理后,果汁中未检出微生物,果汁的L值显著升高。因此采用超高压技术可以改善鲜榨苹果汁的品质。

In order to study the effect of high pressure on the quality of fresh apple juice, 100-800 MPa and 500 MPa combined with 40-60 ℃ heating were conducted on fresh apple juice and the quality index such as phenols content, etc was assayed using HPLC and other methods. The remaining rate of reductive VC in juice decreased firstly, and then increased with the increasing of pressure used. The content of phenols in juice after pressured at 200 MPa had no significant differences compared with it before pressured. The content of phenols in juice after pressured at 400 MPa had no significant differences （P〉0.05） and for juice pressured with 600 MPa the content was decreased little, and pressured with 800 MPa the content was increased. L value of juice decreased after pressured with 200-600 MPa and the color change （AE） was the most for juice with 400 MPa. The moulds and yeasts could not be found in juice after pressured with 300 MPa, and bacteria could not be found after pressured with 400 MPa. The turbidity of juice after pressured decreased, but SS and pH value of juice did not change remarkably （P〉0.05） . Microbes could not be found in juice after conducted with 500 MPa combined with 50 ℃ or 60 ℃, and L value of juice increased significantly. The technology of super high pressure could be used in the quality improving of fresh apple juice.