喷淋预冷工艺参数对荔枝降温特性的影响  

Effects of different spray precooling parameters on cooling characteristics of litchi

作　　者：吕恩利[1] 陈明林 刘妍华 郭嘉明[1] 黄浩[1] 虞新新 李鹏飞[1] Lü Enli;Chen Minglin;Liu Yanhua;Guo Jiaming;Huang Hao;Yu Xinxin;Li Pengfei(College of Engineering, South China Agricultural University, Guangzhou 510642, China;Engineering Fundamental Teaching and Training Center, South China Agricultural University, Guangzhou 510642, China)

机构地区：[1]华南农业大学工程学院,广州510642 [2]华南农业大学工程基础教学与训练中心,广州510642

出　　处：《农业工程学报》2018年第24期292-298,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点研发计划子任务(2018YFD0701002);广东省省级(基础研究及应用研究重大)项目(2016KZDXM028);广东省科技计划项目(2017B020206005);广州市科技计划项目(201704020067);国家自然科学基金项目(51108194)

摘　　要：为掌握喷淋预冷工艺参数对荔枝降温特性的影响,搭建了荔枝喷淋预冷试验平台,以"淮枝"荔枝为试验材料,研究了喷淋温度和喷淋流量对单层荔枝果实以及多层荔枝果实喷淋预冷降温特性的影响。试验结果表明:单层荔枝预冷,喷淋温度越低,冷却系数越大,7/8预冷时间越短,果实温度均匀性越差,选择(5±0.5)℃,能够保持较好预冷均匀性和较快的预冷速度;喷淋流量增大,冷却系数先增大后趋于稳定,7/8预冷时间先缩短后趋于平缓,与喷淋流量呈二次函数关系,果实温度均匀性提高,临界喷淋流量为5.9 L/(s·m^2);多层荔枝堆叠时,果实离喷头越近,冷却系数越大,7/8预冷时间越短,果实温度均匀性越好,相对预冷时间与层数呈二次函数关系,临界预冷层数为4;研究结果为荔枝喷淋预冷装置的设计及单层与多层荔枝预冷应用提供参考。To investigate the effects of spray precooling parameters on the cooling characteristics of litchi fruit, a spray precooling test platform was established.“Huaizhi” litchi fruit was chosen as raw materials for this study. The effects of spray temperature and spray flow rates on the cooling coefficient, 7/8 cooling time, and cooling uniformity, as well as the characteristics of multilayer litchi spray cooling, were studied. For spray precooling of single layer litchi, the lower the spray temperature was, the bigger the cooling coefficient was, the shorter the 7/8 cooling time was, and the worse the temperature uniformity of the fruit was. When the spraying temperature was less than (5±0.5)℃, the 7/8 precooling time was shortened, and the precooling unevenness increased significantly (P<0.05). The effects of spray temperature to achieve rapid precooling was limited. Therefore, a spray temperature of (5±0.5)℃ could be chosen in the actual precooling process, and it could maintain the precooling uniformity and accelerate precooling rate of litchi. With the increase of pray flow rate, the cooling coefficient initially increased and then stabilized, and the 7/8 precooling time initially shortened and then leveled gently, and the fruit temperature uniformity increased. The 7/8 precooling time had a quadratic function relationship with the spray flow rate. The 7/8 precooling time decreased slowly when the spray flow was higher than 5.9 L/(s·m^2). This was because the contact area between the litchi and cold water increased more slowly than the flow rate. Therefore, the flow rate of litchi spray precooling could be selected to be 5.9 L/(s·m^2), which could improve the precooling efficiency and reduce the energy consumption of the pump. When multilayer litchi fruits were stacked, the closer the spray nozzle was, the bigger the cooling coefficient was, the shorter the 7/8 precooling time was, and the better the temperature uniformity was. The relative precooling time had a quadratic function relationship with th

关 键 词：果实 温度 流量 荔枝 喷淋预冷 降温特性 

分 类 号：S375[农业科学—农产品加工] TS255.3[农业科学—农艺学]