Effect of sample properties and infrared power on the penetration depth of infrared radiation into Carum carvi L.

In recent years, infrared radiation (IR) has been considered as one of the suitable methods for drying and decontamination of different spices. However, the low penetration depth of the IR limits its use for food processing in the industry. Due to the importance of Carum carvi as a spice with medical properties, this research aimed to determine the effect of the sample’s structure (powder and seeds), water activity (0.24, 0.56 and 0.89) and the power of IR emitter (222 to 960W) on the penetration depth of the IR into Carum carvi For this propose, the heat fluxes received by copper black body that placed under samples with different thickness was measured. Afterward, the penetration depth was calculated through a mathematical model. The results indicated while aw of the sample, the IR power, and their interaction had a significant effect on the penetration depth of the IR, the structural properties of the sample had no significant effect on it. Increasing the infrared power to 601W enhanced the penetration depth in all of the samples. The highest penetration depth into the powder and the seeds of Carum carvi with aw 0.24 was achieved at the IR power of 601W, and was recorded 4.07±0.27 and 3.85±0.23mm while the samples with aw 0.89 were shown the highest penetration depth when they were irradiated by IR power of 845W) 4.12±0.18 and 4.09±0.13mm). According to the results, determining of IR penetration depth in the spice can be used to determine of their optimal thickness during the infrared food process.