USE OF SOLAR COLLECTORS FOR DRYING MINT LEAVES (Mentha spicata L.)

Abstract

Today, the use of medicinal and aromatic herbs has increased as people move away from synthetic products that have harmful side effects, contain chemical substances that are used as preservatives and treatment agents. Mint leaves (Mentha spicata L.) are included in this group of herbs and they are used in fresh and dried forms. Two drying ovens and a shade-drying method were used in the experiment made for drying mint leaves. Plastic hot water pipes were, coming from the solar collectors, were installed under one of the drying ovens in order to identify the effect of solar collector on the drying process. With the help of hot water, the temperature of the leaves rose up to maximum 53.1 degrees C during operation. This temperature was 14.2 degrees C to 15.1 degrees C higher than the leaf temperature achieved in other drying ovens. Increasing the leaf temperature with solar collectors has shortened the drying time of the leaves. In the drying oven with hot water pipes, the moisture of mint leaves decreased from 86,40 % to 10.61 % in 14 hours, in comparison to wet (fresh) basis, The moisture level on dry-basis decreased from 6.35 g water / g dry matterleaf moisture to 0.12 g water / g dry matter level in 14 hours. This drying time was 4 hours shorter than the other drying ovens, Shortened drying time, improved product quality and decreased energy consumption for drying will increase the aromatic properties of the product as well as its market value.