三种形态叶菜真空预冷过程的比较研究

A Comparative Study of Three Types of Vegetables During the Vacuum Precooling Process

摘要:

本研究以结球甘蓝、白菜和菜心为对象，针对其形态结构差异，在不同预冷终压和处理量条件下对样品进行真空预冷处理，探讨蔬菜包裹形态、紧密程度，叶片非叶脉部分面积占表面积比例和叶片厚度等特点对预冷过程时间、失重率和温差的影响。结果表明，结球甘蓝、白菜、菜心均可经过真空预冷实现快速冷却，在预冷终压500 Pa、处理量2400 g条件下，三种叶菜均能在25 min以内降至4 ℃。但不同压力和处理量条件下，结球甘蓝、白菜和菜心在预冷时间、失重率和温差方面均存在显著性差异（p<0.05）。包裹形态和紧密程度在影响预冷时间和预冷温差方面起主要作用，叶片组织特性包括叶片非叶脉部分面积占表面积比例和叶片厚度则对预冷失重率有较大影响。叶菜的形态结构是影响预冷效果的重要因素，真空预冷压力和处理量的设置需结合蔬菜形态结构特性设定。

Abstract:

Cabbage (Brassica oleracea L. var. capitata L), Chinese cabbage (B. rapa pekinensis), and flowering cabbage (B. campestris L. ssp.chinensis var.utilis Tsen et Lee) were treated with vacuum precooling under different precooling final pressures and processing loads. The effects of leaf wrapping shape, compactness, non-vein leaf ratio, and leaf thickness on the precooling time, weight loss rate, and temperature difference were investigated. The results showed that three types of leafy vegetables (2400 g) were quickly cooled by vacuum precooling to 4℃ in less than 25 min with a precooling final pressure of 500 Pa. Significant differences (p < 0.05) in cooling time, weight loss, and temperature differences among cabbage, Chinese cabbage, and flowering cabbage were observed during the vacuum cooling process at various pressures and processing loads. The wrapping shape and compactness of cabbages affected the precooling time and temperature, and the other tissue characteristics of leaves, including the non-vein ratio and thickness, had major effects on weight loss during vacuum precooling. The morphological structure of the leaf was an important factor affecting the vacuum precooling process, and the final pressure and processing load during vacuum cooling could be determined based on the morphological characteristics of the specific vegetable.