Drying Characteristics and Microbiological Quality Assessment of Solar-Dried Tomato

Mavis Owureku-Asare; Ibok Oduro; Firibu K Saalia; Charles Tortoe; Jonathan Ampah; Kingsly Ambrose

doi:10.1155/2022/2352327

Drying Characteristics and Microbiological Quality Assessment of Solar-Dried Tomato

Int J Food Sci. 2022 Oct 28:2022:2352327. doi: 10.1155/2022/2352327. eCollection 2022.

Authors

Mavis Owureku-Asare¹, Ibok Oduro², Firibu K Saalia³, Charles Tortoe⁴, Jonathan Ampah⁴, Kingsly Ambrose¹

Affiliations

¹ Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, Indiana, USA.
² Department of Food Science and Technology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
³ School of Engineering, University of Ghana, Accra, Ghana.
⁴ Food Research Institute, Council for Scientific and Industrial Research, Accra, Ghana.

Abstract

Tomato (Lycopersicon esculentum) is an important vegetable used in cooking most local foods in Ghana. At the peak season of harvesting, high loses are incurred because of the absence of tomato processing facilities to store, process, and extend the shelf life of fresh tomatoes. Solar drying has been proven to be a more efficient and low-cost method of enhancing quality and adding value to tomato and other vegetables. However, there are concerns about the functionality and quality of the dried products by consumers due to the methods of drying used. In this study, a passive mixed-mode solar dryer suitable for drying tomato was adapted and used to investigate the dehydration characteristics and microbiological quality of the dried tomato. The efficiency of a passive solar dryer was evaluated and used in the processing of fresh tomato to powder. The processing involved the pretreatment of 6 mm slices of fresh Roma variety of tomato by dipping in potassium metabisulfite solution and ascorbic acid solution. The moisture content, moisture ratio, and dehydration rate of solar-dried tomato were assessed. The 24 h dryer efficiency of 24.2% facilitated the drying process of tomato (final moisture content of 12-14%). Aerobic mesophile counts were lower in solar-dried tomato pretreated with potassium metabisulfite (3.90 CFU/g) compared with sun-dried samples (4.85 CFU/g). Solar-dried tomato powder is safer for consumption compared with open sun-dried tomato samples.