真空冷冻干燥条件对多谷物全粉品质影响的研究

Effect of Vacuum Freeze-drying on the Quality Characteristics of Blended Whole Cereal Flour

为获取高品质的多谷物全粉制品,将青麦仁、玉米、青豆三种鲜食谷物混合配比磨浆后,采用真空冷冻干燥方式对其进行干燥处理,以预冻温度、物料厚度、干燥时间为试验因素,从营养品质及物理特性两方面对谷物粉进行考察,并结合感官评价,采用加权平均的方法确定真空冷冻干燥最佳工艺参数。研究表明,多谷物粉最优质量配比为青麦仁、玉米和青豆按3:3:4比例混合,各因素对产品综合品质的影响强弱顺序为干燥时间>物料厚度>预冻温度,在预冻温度-40℃,物料厚度5 mm,干燥时间35 h条件下,测定多谷物全粉中四类营养物质含量分别为维生素C 40.73×10^(-2) mg/g,类胡萝卜素6.25μg/g,蛋白质18.36%,总黄酮1.12 mg/g,此种条件下制得的多谷物全粉产品品质优良、溶解性、复水性较好,吸湿率较低,色泽均一、颗粒细腻、有特有的香气,其吸湿性为5.25%,溶解性为19.67%,复水率为200.68%,综合感官品质得分为96。

To obtain high-quality blended whole cereal flour product, fresh green wheat berry, corn, and green bean were mixed and milled, followed by vacuum freeze-drying. The cereal flour was analyzed for nutritional characteristics, physical properties, and sensory evaluation, using pre-freezing temperature, material thickness, and drying time as experimental factors. The weighted average method was used to determine the optimal operating parameters for vacuum freeze-drying process. The results indicated that the optimum ratio of green wheat berry, corn, and green bean was 3：3：4, and the effects of these three factors on the overall index score were in the decreasing order of drying time material thickness pre-freezing temperature. Under the optimal drying conditions（pre-freezing temperature：-40 ℃, material thickness： 5 mm, and drying time： 35 h）, the composition of vitamin C, carotenoids, proteins, and flavonoids of the blended whole cereal flour were 40.73×10^（-2）mg/g, 6.25 μg/g, 18.36%, and 1.12 mg/g, respectively. Under the aforementioned optimal conditions, the prepared blended whole cereal flour had high quality, good solubility（19.67%）, good rehydration ratio（200.68%）, low hygroscopicity（5.25%）, uniform color, fine particles, and unique aroma, with a comprehensive sensory quality score of 96.