超高压加工鲜榨苹果汁过程中的主要理化变化

The Physical and Chemical Changes During High Pressure Extracting Processing of Fresh Apple Juice

在50℃协同320MPa加工鲜榨苹果汁的过程中,利用果汁的L*值和b*值升高,a*值降低,但幅度均不大。高效液相色谱(HPLC)等方法测定表明:酚类在加工中由于氧化而减少,果汁中单宁、绿原酸、总酚和表儿茶素的保留率(与原料对比)分别为80.2%、82.4%、78.2%和82.6%。还原型V_c和总V_c分别减少43.7%和6.1%。气/质联用(GC-MS)的检测和分析表明:热协同压力处理鲜榨苹果汁后各风味成分变化在0.28%～6.16%,总风味物质压后比压前仅下降0.78%,酯类物质在压后含量增加。50℃协同320MPa加工工艺能较好地保持苹果汁的品质。

During the processing of 320MP pressure at 50℃ in fresh apple juice extraction, there was no obvious increase of L^＊ -value and b^＊ -value and decrease of a^＊ -value. HPLC analysis showed that the amount of polyphenols in juice was decreased because of oxidization. The amount of polymeric and mono proanthocyanidin, chlorogenic acid, totol phenols and epicatechin in cloudy apple juice retained 80.2% ,82.4% ,78.2% and 82.6% respectively. The reduced VC and total VC decreased 43.7% and 6.1% respectively. The volatile components changed in the scope of 0.28～6.16% and the total volatile component only decreased 0.78%, the amount of esters increased. The process condition of 320MP at 50℃ was the best condition to maintain the quality of fresh apple juice.