干燥方法对速食薏米粉干燥特性与品质的影响

采用微波干燥(MD)、微波对流干燥(MCD)、热风干燥(HAD)和传统烤制法(TR)4种干燥方法对高压汽蒸熟制薏米进行干燥制备速食薏米粉,考察4种干燥方法对薏米的干燥特性,并比较其对薏米粉色泽、营养成分、冲调特性和感官评价的影响。结果表明:在干燥特性方面,MCD所用时间最短,仅为26 min,其次为TR,为35 min,HAD所用时间最长,为90 min,且MCD的平均干燥速率最高。在色泽方面,选用MCD方法处理的样品颜色偏黄,更接近于新鲜薏米粉的色泽。在营养化学组分特性方面,干燥后的薏米粉中灰分、粗脂肪、蛋白质、总糖和还原糖的含量均有损失,其中MD对灰分和总糖损失最少;MCD对蛋白质和还原糖的保留最好;TR干燥后的粗脂肪含量最高为7.02 g/100 g。冲调特性方面,MCD制备的产品堆积密度最低,休止角最小,流动性最好,水合能力最高;TR制备的薏米粉的润湿下沉性和分散性时间最短,结块率和吸湿率最低。MCD 样品获得最高的感官评价分84.8分。综合评价相对HAD和TR,MCD干燥速率快、品质好。

Effect of Drying Methods on Drying Characteristics and Quality of Instant Coix Seed Flour

The instant coix seed flour was prepared by microwave drying (MD), microwave convection drying (MCD), hot air drying (HAD) and traditional roasting (TR) and their drying and rehydration characteristics, color, nutritional compound, solubility property and sensory evaluation were compared. The results showed that in terms of drying characteristics, MCD took the shortest time, only 26 min, followed by TR, 35 min, and HAD had the longest time, 90 min. And MCD had the highest average drying rate. In terms of color, the sample treated by MCD method was yellowish, which was closer to the color of fresh coix powder. In terms of nutritional compound, drying caused the lost of the contents of ash, crude fat, protein, total sugar and reducing sugar in dried coix seed flour. MD had the least loss of ash and total sugar, MCD had the best retention of protein and reducing sugar, and TR had the highest content of crude fat of 7.02 g/100 g. In terms of solubility property, MCD prepared products had the lowest bulk density, the lowest angle of repose, the best fluidity and the highest hydration ability, while TR prepared coix powder had the shortest wettability and dispersibility time, and the lowest caking rate and moisture absorption rate. MCD samples obtained the highest sensory values of 84.8. Through comprehensive evaluation, MCD with the highest drying efficiency and the best quality.