Effect of drying temperature, airflow rate and flower types on dried saffron flower quality

Abstract

The separating of saffron stigma from fresh flowers is the most important and the most difficult step of saffron harvesting. The separating of saffron stigma is done with the hand labor, and it have time-consuming and costly. The saffron flowers will be decay if separating of saffron stigma is not done quickly.  Drying is one method of keeping saffron. The dried saffron flowers have the higher shelf life, and there have more time for separating of stigma. The main object of this study was to determine the best saffron flower drying method. Therefore, the effect of variables including drying temperature in three levels (40, 50 and 60 °C), airflow rate in two levels (0.5 and 1 m/s) and three levels of flowers (buds, semi opened and fully opened) were investigated on the amount of crocin (stigma color), saffronal (fragrance) and picrocrocin (bitter taste). The results showed that the amount of crocin decreased and the amount of saffronal increased with increasing of drying temperature. The best conditions for flowers drying were obtained with 50 °C drying temperature and 0.5 m/s airflow rate. The dried saffron flower buds had the higher amount of saffronal than dried flowers of semi opened and fully opened.