The Impact of a Combined Infrared-Hot Air System on the Thawing Process and Quality Attributes of Carrots

Vegetables are perishable and cultivated seasonally. The aim of this study was to employ a combined thawing through hot air-infrared system, while investigating the effects of temperature, airflow velocity, and infrared radiation power on thawing time and the quality attributes of thawed carrots. In this research, carrot samples, having been washed and shaped using a cylindrical mold measuring 22.5 mm in diameter and 12 mm in height, were subjected to freezing at -18°C for 48 hours. Thawing parameters were air temperature (30°C and 40°C), airflow velocity (0.5  and 5 m/s), and infrared power (100 and 300 watts). The sample thawed at 25°C was control sample. Data analysis showed that reciprocal effect of increasing temperature, power of the radiation source and air flow speed had a significant effect on the thawing time, vitamin C, β-carotene, the thawing loss, and pH (P≤0.05). This system was able to significantly reduce the thawing time this time for the control sample was 47.66 minutes and for the shortest thawing time, the treatment 8 (F5P300T40) was 6.23 minutes. The lowest pH value was related to treatment 7 (F0.5P300T40) 5.81 and the highest value was related to treatment 1(F0.5P100T30) 6.15. The highest amount of β -carotene was related to treatment number 8 (F5P300T40) 48.12 mg/100g and  the lowest amount was related to treatment 5 (F0.5P100T40) 14.03 mg/100g. The highest amount of vitamin C was related to treatment 4(F5P300T30) 12.36 mg/100g and the lowest amount was related to treatment 1(F0.5P100T30) 3.68 mg/100g. . In the thawing loss, the highest amount was related to treatment 1 (F0.5P100T30) 19.7% and the lowest amount was related to the control sample7.44%. . Due to the low start-up cost, shorter process time and favorable quality, hybrid defrosting is widely used in the food industry.