山核桃坚果热风干燥特性及其工艺参数优化

Hot-air drying characteristics and technical parameters optimization of kernel hickory(Carya cathayensis Sarg.)

针对山核桃坚果热风干燥质量难以控制、干后品质差等问题,采用单因素试验方法,研究了热风温度、装载量及风速对山核桃坚果干燥特性的影响。通过3因素5水平的二次回归正交试验,分析了热风温度、装载量及风速与干燥过程单位时间干燥速率、单位质量干燥能耗以及干后物料蛋白质保存率、不饱和脂肪酸保存率、感官品质指标综合分值的关系,建立了二次回归数学模型,分析了3因素对各指标影响的显著性;利用多目标非线性优化方法,确定了山核桃坚果热风干燥的最佳工艺参数组合,即热风温度为72℃,装载量为0.08kg,风速为65m/min。在此条件下,单位时间干燥速率为0.458%/min、单位质量干燥能耗为5.986kWh/kg、蛋白质保存率为92.12%、不饱和脂肪酸保存率为90.65%、感官品质指标综合分值为32.89分,综合评分为0.802。研究结果为山核桃坚果的干燥和工业化生产提供一定的理论依据。

According to the proplems of difficult control for hot-air drying process and poor quality of dried hickory kernels（Carya cathayensis Sarg.）,the effects of drying temperature,material load and airflow rate on hot-air drying characteristics of kernels were investigated by the single factor experimental method.The quadratic regression orthogonal experimental method with three factors and five levels for each factor was employed.Drying temperature,material load and airflow rate were the influence factors,and dehydration rate,energy consumption of drying process,protein retention ratio,unsaturated fatty acid retention ratio and synthetic score of sensory quality indicator of dried kernels were the experimental indices.The relationships between the experimental indices and the influence factors were analyzed.The regression mathematical models describing the relations between the experimental indices and the influence factors were established to analyze the influence degree of the factors on the experimental indices.The optimal combination of technological parameters for drying materials was obtained by multi-objective nonlinear optimization method.The optimal parameters were as follows：hot-air temperature 72℃,material load 0.08 kg,and airflow rate 65 m/min.Under these conditions,dehydration rate was 0.458%/min,energy consumption was 5.986 kW？h/kg,protein retention ratio was 92.128%,unsaturated fatty acid retention ratio was 90.65%,comprehensive score for sensory quality indicator was 32.89,and overall score was 0.802.The results can provide a theoretical basis for drying and industrialized production of hickory kernels.