Effect of the drying air conditions on the drying rate and milling quality of a long-grain rice variety

Abstract

This work aims to study the effect of different drying air conditions on the drying rate and milling quality of a Uruguayan long-grain rice variety. It was observed that increasing the drying air temperature or lowering the drying air relative humidity decreased the milling quality. At temperatures above glass transition, this effect was greater. However, it was possible to dry the rice at a drying rate of up to 3 percentage points of moisture per hour (on a dry basis) maintaining a high milling quality. This was achieved when a 1-hour tempering was performed after drying. At higher drying rates, the milling quality decreased sharply even when tempering was performed. These results aim to contribute to the understanding of the drying process, allowing its optimization by increasing the drying rate without losing milling quality.

Keywords:
rice; rice drying; drying rate; milling quality; glass transition