Development of a complementary-frequency strategy to improve microwave heating of gellan gel in a solid-state system

Abstract

As a helpful step towards the future development of a solid-state microwave system that can dynamically control microwave source parameters to deliver better heating performance, a complementary-frequency heating strategy has been developed and will be discussed here. The proposed complementary-frequency heating strategy is based on potential microwave heating uniformity enhancement through microwave frequency shifting during heating has shown promise to improve the microwave heating performance. The average temperature and heating uniformity results of this strategy were compared to conventional heating strategies like Fixed-Frequency and Sweeping-Frequency strategies. Typically, the Complementary-Frequency strategy could selectively use specific frequencies in the microwave heating process. These frequencies could be identified based on their associated complementary temperature profile of the top surface of the food product collected by a thermal imaging camera and sequenced in a specific order dictated by a predefined algorithm. The results indicated that both the Sweeping-Frequency and the Complementary-Frequency strategies could uniformly heat food products more than the Fixed-Frequency strategy. Meanwhile, the Complementary-Frequency strategy can trade-off microwave power absorption efficiency and heating uniformity to deliver a higher heating rate than the Sweeping-Frequency strategy does. • Complementary heating patterns were utilized to develop the frequency-shifting strategy. • The Complementary-Frequency strategy can be developed to balance efficiency and uniformity. • The Complementary-Frequency strategy could improve the microwave heating performance.