Abstract:

【Objective】 The experiment was carried out to study the factors affecting intermittent microwave drying on maize seeds, to research the optimal conditions for drying maize seed. 【Method】 Many factors affecting seed moisture content and seed germination in the processing of microwave drying were studied, which included time ratio of intermittent microwave, primary moisture of seed, loading weight in drying and microwave drying power. 【Result】 Microwave drying power and time ratio of intermittent microwave were the key factors affecting intermittent microwave drying on maize seeds. The preferable time ratio of intermittent microwave was 10% on the condition of 700W or 800W of microwave output power. But in continuous drying, the seed moisture shouldn’t be more than 16.38% at 800W output power and not more than 17.29% at 700W output power. On the condition of discontinuous microwave drying, maize seeds of primary moisture content 18% can be dried with output power 800W and 10% or 20% time ratio of intermittent microwave. In different processing times of discontinuous microwave drying, drying times could be calculated with formulation y1=23.9160e-0.1426x1+ 3.4943e-0.0114x1 (10% of time ratio of intermittent microwave) and formulation y2=2.0466+11.1693e-0.2457x2 + 9.306e-0.2457x2 (20% of time ratio of intermittent microwave) respectively, for maize seed moisture reduced from 18% to 13.5%. The biggest drying rate was observed when loading weight was 300 g, but the damage of seed was the most serious at this very moment. 【Conclusion】 There were many factors affecting drying seed efficiency, such as microwave drying power, time ratio of intermittent microwave, primary seed moisture, loading weight in processing, and pattern. Selecting proper conditions and mode of microwave processing according to the above results, the purpose of ensuring seed drying efficiency and planting value could be achieved.

Key words: intermittent microwave, drying characteristics, maize seed, germination percentage