基于低温预处理的非油炸胡萝卜脆片的干燥工艺研究

Research on Drying Technology of Non-Fried Carrot Chips Based on Low Temperature Pretreatment

由于新鲜胡萝卜木质素含量较高,经预干燥-压差膨化干燥后获得的制品存在质地坚硬、口感差的问题,文章采用冷冻对新鲜胡萝卜进行干燥预处理,在不同温度(4、–5、–9℃和–16℃)条件下对胡萝卜片进行预处理12 h,然后采用热泵干燥、红外压差膨化干燥的组合干燥法进行胡萝卜片干制加工,探究低温预处理对热泵干燥动力学、胡萝卜脆片色泽、膨化度、复水特性的影响规律,并优化预干燥后含水率的水平,以期提高干燥后胡萝卜脆片的品质以及口感。结果显示,低温处理能够显著提高胡萝卜的干燥速率和膨化度,而预干燥的含水率也会作用于干制品的膨化水平,并且随着预干燥含水率的降低,胡萝卜的复水性越好。胡萝卜脆片的最优干燥工艺为使用–16℃对胡萝卜片进行预处理,通过热泵干燥将胡萝卜片的含水率干燥到30%,随后进行压差膨化,能够得到满足预期的胡萝卜脆片。

Due to the high lignin content of fresh carrots,the products obtained after pre-drying and explosion puffing drying suffer from issues such as a hard texture and poor taste.In this study,freezing was employed to dry fresh carrots,and the carrot slices were pretreated at different temperatures(4,–5,–9℃,and–16℃)for 12 hours.Subsequently,a combined drying method involving heat pump drying and infrared explosion puffing drying was utilized for drying the carrot slices.The impact of low-temperature pretreatment on the drying kinetics of heat pump,color retention,swelling degree,and rehydration characteristics of carrot slices was investigated in order to optimize the moisture content level after pre-drying.This optimization aimed to enhance the quality and taste of dried carrot slices.The results demonstrated that low-temperature treatment significantly improved both the drying rate and swelling degree of carrots.Additionally,it was found that the moisture content during pre-drying also influenced the swelling level of dry products,lower moisture content resulted in better rehydration properties for carrots.The optimal process for producing carrot chips involved pretreating them at–16℃followed by reducing their moisture content to 30%through heat pump drying before conducting explosion puffing drying to obtain desired carrot chips.