混浊梨汁的微波预处理工艺

The microwave pretreatment processing of the crisp pear cloudy juice

梨汁褐变是梨汁加工和贮藏过程中的主要技术难题之一,严重影响了梨汁的外观、风味等品质,降低了梨汁的价值。梨汁的褐变分为酶促褐变和非酶褐变两种,酶促褐变是加工过程中发生褐变的主要原因。为保持混浊梨汁的品质,本研究以酥梨为实验材料,采用微波处理对破碎前的酥梨进行处理。讨论了微波时间、功率对混浊梨汁的酶活及色值的影响,结果表明微波处理是一种有效的钝化多酚氧化酶活性的方法。在微波时间、功率单因素实验的基础上,结合抗坏血酸浸泡处理设计正交试验。得出微波功率对多酚氧化酶活性有显著影响,最佳工艺条件是在微波功率720W、微波时间20s、用3mM抗坏血酸浸泡15min,在此条件下,不仅能较好的保持果汁的色泽,降低多酚氧化酶的活性还能使果汁中总酚得到较好的保存。

The browning of pear juice was one of the major technical challenges during storage and processing.It reduced the value of pear juice such as the appearance,flavor and other quality.The browning of pear juice was made of enzymatic and non-enzymatic browning,and the enzymatic browning is the main cause browning during processing.In this paper,the effects of microwave pretreatment on pear processing were explored by studying the polyphenol oxidase （PPO） characteristics and color in crisp pear.The combined pretreatments of microwave and ascorbic acid could maintain the good quality with the reduced amount of ascorbic acid and also reduce or avoid scalding hot cooked smell.The microwave pretreatment parameters for cloudy pear juice were as follows：microwave outpower 720W,processing time 20s,the ascorbic acid concentration 3mM,and soaking time 15min.