Temperature and Quality Characteristics of Infrared Radiation–Dried Kelp at Different Peak Wavelengths

Abstract Drying experiments on kelp (seaweed species) were conducted using air drying (AD) and infrared radiation drying (IRD) at different emission peak wavelengths of 2.4, 3.0, 5.0, and 6.0 µm. Temperature characteristics of the dried kelp were determined in terms of temperature distribution and surface–interior temperature variation. Rehydrated ratio, color, and texture before and after rehydration were measured to evaluate the quality of dried kelp products. Dielectric properties were also studied to observe the characteristics of rehydrated dried products. The results indicated that the total drying time required for IRD products was approximately 120 min, reduced by 56% compared to AD (275 min). Infrared-dried products at 2.4 μm wavelength and AD products were found to be more uniform from the thermal images and had higher rehydration ratios compared to others. IR-2.4 rehydrated products were the closest to blanched samples in hardness, springiness, cohesiveness, and chewiness. This research work concluded that infrared radiation drying has potential to be used for drying of kelp. Keywords: Air dryingDielectric propertiesInfrared dryingKelpQuality ACKNOWLEDGMENTS The authors thank Senttech Infrared Technology Co., Taizhou, China for technical assistance. Notes Results are mean ± standard deviation; values followed by different letters in the same column are significantly different (p < 0.05). Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/ldrt.