Pineapple drying: mathematical modelling and experiments using high-precision system and a greenhouse-type solar dryer

Abstract

The most economical option for preserving agricultural products has been solar drying. However, new knowledge and technology are currently required for drying large quantities of products, where quality and food safety are requirements that dehydrated products must meet. Performance optimization of solar dryers according to the characteristics of the product and the environment is especially required. The main goal in this research was to generate basic knowledge to improve the management of solar drying of pineapple (Ananas Comosus, L.) under greenhouse–type dryers. Two drying experiments were carried out to generate thin-layer models for pineapple fruit. The first used a high-precision laboratory dryer at the University of Hohenheim, Germany. Pineapple drying curves were obtained under constant air temperatures, relative humidity and air velocity. The second experiment was conducted in a greenhouse-type solar dryer at Silpakorn University, Nakhon Pathom, Thailand. Pineapple drying curves were determined under variable conditions of air temperature, relative humidity and air velocity. It was found that the thin-layer mathematical model proposed by Hasibuan and Daud predicts adequately the moisture content measurements of the product in both experiments.