Effect of duration and drying temperature on characteristics of dried tomato (Lycopersicon esculentum L.) Cochoro variety

Abstract

The objective of the present study was to standardise the duration and temperatures of the conventional oven drying methods for best physical and sensory characteristics of dried tomato. The experiment consisted of two factor factorial design (3*2) with three levels of drying temperature (70°C, 80°C and 90°C) and two levels of drying duration (7 and 8 hours) with three replications. An improved and high yielding variety (Cochoro) of tomato released in 2007 for processing and widely grown in Ziwai (Maki), Ethiopia was used. Prior to drying, individual tomato fruits were washed and sliced into uniform thickness (8mm); then, the slices were placed on to the drying trays in a single layer to facilitate uniform drying in hot air oven set at predetermined temperatures per the respective treatments. Data were collected on different physical and sensory attributes and analysed using SAS software (version 9.2). The results showed that titratable acidity, total soluble solids and water absorption capacity were significantly (p≤0.001) increased due to the interaction of degree of temperature and duration of oven drying. In contrast, pH and water activity decreased as the drying temperature and duration increased. Drying at 70°C for 7 hours produced dried tomatoes with the highest sensorial acceptability and physical attributes while higher temperatures (80, 90°C) and longer duration (9 hours) significantly detract the quality of dried tomato. Hence, it is possible to add value and preserve tomatoes through oven drying at the right temperature and optimum duration.