Abstract: To obtain a more energy-efficient thawing approach, quick-frozen maize was thawed by microwave field technology in either a continuous or intermittent mode under conditions of varying number of maize ears in this paper. The regularity of temperature change in different parts of maize ear and its effect on microwave energy absorption were explored. The results showed that different parts of maize ear displayed identical temperature change trend during both continuous and intermittent thawing. The surface of maize ear exhibited the highest temperature, followed by grain temperature and cob temperature during the early stages of thawing. As the thawing time was prolonged, the central temperature of maize cob was promptly elevated, forming a temperature gradient from the central axis of maize cob to the surface of ear. In comparison with continuous thawing, intermittent thawing resulted in more even temperature distribution and higher microwave energy absorption, which rose as the number of maize ear was increased and tended to remain stable at 50.2% until the number of maize ear reached 4.

Key words: quick-frozen maize, intermittent microwave thawing, microwave absorption efficiency