Quality variation management for drying process in Thai agro-industry

Abstract

Drying process is a very important process for Thai agro-industry. It is used to preserve agricultural products in order to prolong their shelf lives by reducing their moisture content to the quality target. However, a major problem related to the quality of the dried product is still found. The dried product cannot be reduced the moisture content to its target. Therefore, this aim of this dissertation is to manage the quality variation for drying process in Thai agro-industry. This dissertation is conducted with four types of the dried product as paddy rice, cassava chip, tobacco, and longan. All of them are important commercial product for Thailand. This dissertation begins with finding the drying time for each drying phase. After that, fuzzy c-means clustering is selected to organize the raw materials into the same clusters. It can help to reduce the dried product quality variation from the variety of the raw material. As a result, three clusters as low, medium, and high moisture content are the optimal number of clustering. After clustering, the raw materials are transferred to the drying process which can be divided into three phases as heating, drying with a constant drying rate, and drying with falling rate phases. The optimal drying temperature level and the mathematical model representing the behavior of the moisture content during the drying period are obtained. Moreover, adjustment drying temperature period is added and proposed by this dissertation to minimize the dried product quality variation.