Thin layer drying characteristics and chemical properties of two local plantain varieties

Abstract

Abstract Plantain (Musa paradisiaca) is a key staple in Ghana, yet postharvest losses persist due to poor preservation. Drying offers a practical remedy, but data on cultivar-specific kinetics and chemical characteristics are limited. This study examined thin-layer drying behaviour, modelling, moisture diffusivity, activation energy, composition and microbiological quality of Apem and Apantu plantains with and without blanching. Sliced samples (5 mm) were blanched (90°C, 3 min) or untreated, then dried at 70°C for 6 h under uniform conditions (±0.5°C). The drying temperature of 70°C was selected because it balances rapid moisture removal with preservation of nutritional quality, operating within the typical range (60-80°C) used for starchy tropical crops while avoiding thermal degradation of heat-sensitive nutrients. Moisture declined mainly in the falling-rate phase. Unblanched samples reached lower final moisture (6.85–8.76%) than blanched ones (18.48-18.87%), with unblanched Apantu performing best. Diffusivity ranged from 7.87×10-6 to 1.26×10-5 m2/s, while activation energy was 24.86-32.71 kJ/mol. Blanching reduced diffusivity and increased energy, especially in Apem. The Page model best described most data (R2>0.998). Unblanched Apantu retained superior nutrients (ash 2.56%, protein 2.22%, fibre 1.87%), whereas blanching caused major leaching losses in minerals, protein and fibre. Colour retention improved with blanching in Apantu. Microbial counts remained within safe limits despite post-blanching contamination risks. Overall, unblanched Apantu proved optimal, highlighting the need for cultivar-specific drying strategies to enhance quality, reduce losses and support Ghana’s plantain industry through improved processing efficiency and commercial adoption opportunities.