Influence of pulsed vacuum drying on drying kinetics and nutritional value of corn kernels

摘要

Effects of different drying temperature (45, 50, 55, 60, and 65 degrees C), vacuum duration time (VDT; 7, 11, 15, and 19 min) and pulsating cyclic time (PCT; 7:2, 11:3, 15:4 and 19:5 min min(-1)) on the drying characteristics and quality of corn kernels were investigated. Reduce the PCT could enhance the whole drying process. Weibull distribution function has high fitting precision for describing the pulsed vacuum drying (PVD) kinetics of corn kernels (R-2.99). TheE(a)value under PVD was calculated as 36.9 kJmol(-1). Meanwhile, the main nutritional components of corn showed declining trend with the increase of temperature and PCT, while it oscillated with the prolonged VDT. The total score decreased with the heightening of drying temperature and fluctuated with the extension of VDT and PCT parameters. Considering the total drying time and quality comprehensive score of corn, the optimal drying parameters was confirmed at 50 degrees C with the pulsing ratio of 7:2 min min(-1). Practical Applications Corn is treated as an important crop because of its various nutritional ingredients and has been commonly cultivated all over the world. Due to its water-rich characteristics, fresh maize kernels would subject to various deterioration reactions during storage and hence reduce the content of nutrients. However, the samples have high compactness and tough epidermal structure, which limited the water diffusion efficiency during processing. Pulsed vacuum drying technique has been widely applied to agricultural products drying in China benefiting from its high heating efficiency. Currently this technology is successfully used in lemon, wolfberry, Chinese ginger, and seedless grape. This study will help in revealing the impact of PVD parameters on drying characteristics and quality of maize kernels, which is of great significance to optimize the processing efficiency through the alternative pressure circulation and consumer acceptance of dried products.