微波干燥条件对杏脯干燥特性与品质的影响

目的:提高杏脯的干燥效率及产品品质。方法:分别用转盘式微波炉(RMD)和微波对流耦合干燥机(MCD)干燥杏脯，考察微波功率、微波发射方式、切分程度及物料是否转动对杏脯干燥特性、焦化率、色值、感官品质及复水特性的影响，并与传统热风干燥(HD)进行比较。结果:与HD的1 040 min(16块)和840 min(48块)相比，微波干燥显著缩短干燥时间，不同微波干燥条件下所需的干燥时间为40～400 min;脉冲比越大或功率越高或物料尺寸越大，干燥所用时间越短，在MCD中控温微波干燥耗时最长。无论是在RMD还是不控温MCD中静态干燥，杏脯均出现严重的烧焦现象，焦化率为17%～100%,物料转动时焦化率高于静态干燥的，而在MCD中控温静态干燥避免了物料的烧焦现象，且MCD中控温静态干燥的杏脯色值和感官评价最接近HD的，复水比与HD仅相差3.45%～5.17%,获得最高的感官评价分(87.2分)。结论:MCD中控温静态干燥可以作为杏脯的高效干燥方法。

Effects of different microwave drying conditions on drying characteristics and quality of preserved apricots

Objective: This study aimed to improve the drying efficiency and product quality of preserved apricot. Methods: The preserved apricots were dried using the rotary microwave oven (RMD) and the microwave coupled with convection dryer (MCD). The effect of microwave power, microwave emission mode, cutting and material movement on drying characteristics, the scorching rate, color and sensory quality were investigated and compared with traditional hot air drying (HD). Results: Compared with 1 040 min (16 pieces) and 840 min (48 pieces) of HD, the drying time was significantly shortened by microwave drying, ranging from 40 to 400 min. The drying time could be shorten by large pulse ratio, high power or large material size, and the longest drying time was in MCD temperature controlled microwave. Both RMD and MCD static drying caused serious charring phenomenon in apricots, with the char rate ranging from 17% to 100%, which was higher than that in static drying. However, the char phenomenon was avoided in MCD static drying, and the color value and sensory evaluation of apricots in MCD static drying were closest to HD. The rehydration ratio was only 3.45%~5.17% different from HD, and the highest sensory evaluation score (87.2 points) was obtained. Conclusion: MCD temperature-controlled static drying can be used as an efficient method for apricots.