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

摘要:

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6.25 μg/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。

Abstract:

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.