A study of the effect of the drying process on the composition and physicochemical properties of flours obtained from durian fruits of two ripening stages

Abstract

Summary: Durian cv. Monthong with two ripening stages (unripe and fully ripe) was subjected to microwave vacuum drying (MWD) at 5.49 W g-1 and hot air drying (HAD) at 60 °C. With an increase in ripening degree, the starch content was significantly (P ≤ 0.05) decreased from 40.08-40.42% to 9.44-11.76%. X-ray diffraction indicated that the crystalline pattern was changed from starch to sucrose. The starch granule morphology of durian flour was conserved for both drying conditions. Peak gelatinisation temperatures of MWD and HAD flours were increased significantly (P ≤ 0.05) from 56.71-57.32 to 60.71-61.23 °C. Using different drying methods, MWD flour had less a*-value (P ≤ 0.05) than HAD flour. The peak viscosity and trough of the HAD unripe durian flour (5.92 RVU and 3.45 RVU, respectively) were significantly (P ≤ 0.05) lower than those of the MWD unripe durian flour (34.32 RVU and 11.57 RVU, respectively). © 2013 Institute of Food Science and Technology.