EFFECTS OF TEMPERATURES ON PHYSICOCHEMICAL PROPERTIES OF CELERY (Apium graveolens L.) SLICES DRIED BY INFRARED DRYER

In this study, drying characteristics, color values, and optimum thin layer drying model of celery slices were determined by drying them in a temperature-controlled infrared dryer. Changes in surface area and sphericity of celery slices throughout the drying process were also determined. Present findings revealed that temperature was a significant criterion for drying the celery slices. Decreasing drying times were observed with increasing drying temperatures. Drying operations were carried out at three different temperatures (50, 60, and 70 ºC). The longest drying time (7.25 hours) was observed at 50 ºC and the shortest drying time (4.25 hours) was achieved at 70 ºC drying temperature. The closest fresh color values to the color values of the fresh product were obtained from 60 ºC drying temperature. In terms of chroma values, the closest value to the fresh product was observed again at 60 ºC. The most used Page, Midilli-Küçük, Yagcıoglu, and Jane Das thin-layer drying models were used to generate drying curves of celery slices. Among these models, the Midilli-Küçük model yielded the greatest R2 value, thus it was selected as the best thin-layer drying model for celery slices.