Optimization of Drying Conditions for Quality Dried Tomato Slices Using Response Surface Methodology

Abstract

The response surface method was used to investigate the results of experiment designed with the Box‐Behken approach to make known the effects of air temperature, air velocity and sample thickness, on drying time, lycopene content, ascorbic acid content, non‐enzymatic browning and color of dried tomato slices. Three levels of temperature (40 to 60C), air velocity (1.0 to 2.0 m/s) and sample thickness (7 to 11 mm) were used for the experiment. The desirability index technique was used to predict the ideal drying condition. At the best conditions of 44C air temperature, 2.0 m/s air velocity and 7.72 mm sample thickness, drying time was 527 ± 76 min, lycopene content was 62.7 ± 4.3 mg/100 g dry matter, ascorbic acid content was 3.07 ± 0.14 mg/g dry matter, brightness value was 62.92 ± 2.18, ratio of redness to yellowness was, 0.78 ± 0.05 and the non‐enzymatic browning index was 0.55 ± 0.06 absorbance unit. Practical Applications The research took practical desires of minimum drying time and non‐enzymatic browning and maximum values of lycopene content, ascorbic acid, color brightness and redness to yellowness ratio into consideration. These quality indicators are of topmost importance to the food industries involved in tomato drying. The quality of dried products obtained using response surface methodology provides industries with optimized conditions for improving the quality of dried tomatoes. The dried product is a valuable ingredient in the preparation ready to enjoy soups, sauces and pizzas.

Influence of process parameters on the energy requirements and dried sliced tomato quality

“…Quality of dried food products is generally assessed by its nutritional value, acceptability and safety. The degree of acceptability of dried products majorly depends on color and taste attributes and drying as welair condition (drying air temperature, air velocity, and air relative humidity) and moisture content. For sliced vegetables, the optimal selection of drying conditions depends on the total drying duration whereas the price of the dried product depends on its final quality .…”

“…For sliced vegetables, the optimal selection of drying conditions depends on the total drying duration whereas the price of the dried product depends on its final quality . These optimal conditions also help in preserving the product nutrient, minimize energy requirements for drying, operation cost with marginal upturn in economic input and gross reduction in greenhouse gas (GHG) emissions …”

“…Some studies on energy requirements for drying of sliced agricultural products such as, pepper slices; onion slices; sliced banana, mango, potato, apple; ginger slices revealed that by increasing air temperature at constant sample thickness and air velocity, the energy requirements, drying duration, and dryer energy consumption decrease, thus increase in drying rate. Similarly, experimental studies have been done on drying conditions for quality sliced dried products using different drying systems . In Nigeria, the interest in studies that investigate process conditions and energy requirements for good dried quality of tomato is recent.…”

Recent developments in drying of food products

“…Where MR is moisture ratio, M t is moisture content at any given time (kg water kg-1 solids), M e standing for equilibrium moisture content (kg water kg-1 solids) and M 0 representing the initial moisture content. Abano et al [1] investigated the drying characteristics like air velocity, drying time, etc. of tomato slices using RSM modeling technique and the ideal drying condition is predicted using desirability index technique.Akpinar [3] investigated the drying characteristics of mint leaves using an indirect forced convection solar dryer.…”

Optimization of Drying Conditions ofXanthosoma sagittifolium(Tannia) Tubers in Tray Dryer Using Response Surface Methodology

“…However, this method is extremely weather dependant, and the final product might be contaminated with dust, sand, insect and other foreign materials (Midilli ; Abano et al . ). To improve the quality of the product industrial drying methods like hot air drying, which utilizes closed equipment should be used in place of sun drying (Doymaz and Pala ; Ertekin and Yaldiz ; Misha et al .…”