响应面试验优化酶解辅助喷雾干燥制备怀山药粉工艺

为获取溶解性和冲调性较好的怀山药粉，改善怀山药粉的喷雾干燥效果，以普通怀山药为原料，采用酶解辅助喷雾干燥的方法制备怀山药粉，并用响应面法优化酶解液的喷雾干燥条件。分析热风温度、热风流量、进料流量的变化情况对怀山药出粉率的影响规律，并对怀山药粉的基本成分含量及特性指标进行测定。结果表明：在α-淀粉酶添加量0.2%、温度70 ℃、pH 7.0、酶解时间45 min的条件下，怀山药中可溶性固形物得率达82.79%，当酶解液真空浓缩至质量分数17%时，对其进行喷雾干燥，在热风温度180 ℃、热风流量28.60 m3/h、进料流量1 060 mL/h条件下，怀山药出粉率最高达到37.59%，且制得怀山药粉冲调性好，色泽风味佳，含水率小于5%，适于长期贮存。因此，酶解与喷雾干燥相结合的方法制得怀山药粉品质较优。

Response Surface Optimization of the Preparation of Chinese Yam Powder by Enzymatic Hydrolysis Followed by Spray Drying

The purpose of this work was to obtain Chinese yam powder with better solubility and reconstituability through
enzymatic hydrolysis followed by spray drying. The optimization of spray drying parameters for improved drying efficiency
was carried out by using response surface methodology (RSM), where the effects of air-inlet temperature, hot air flux and
feed flow rate on the powder yield of dried yam were analyzed. Proximate composition and properties of the power product
were determined. Results showed that the total soluble solids content of yam hydrolysate was 82.79% when the hydrolysis
was performed using 0.2% α-amylase for 45 min at 70 ℃ and initial pH 7.0; after subsequent vacuum concentration to
17%, the hydrolysate was spray dried at an air-inlet temperature of 180 ℃, air flow rate of 28.60 m3/h, and feeding rate of
1 060 mL/h, resulting in a powder yield of 37.59% with good solubility, color and flavor, water content smaller than 5%, and
high suitability for long-term storage. Therefore, the combination of enzymatic hydrolysis and spray drying method allows
the production of higher-quality Chinese yam powder.