Document Type : Original Article
Authors
1 Agricultural Engineering Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
2 Agricultural Engineering Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
3 Research Institute of Forests and Rangelands, Agricultural Research, Education and Extension Organization (AREEO), Tehran, Iran
Abstract
Production of dried Rosa flower bud with high quality of color and essential oil is concerned for related industries. Six methods of drying process contain shade drying, indirect solar dryer, cabinet dryer in three levels of inlet air temperature (40, 50, 60 oC) and freeze dryer were compared together in order to dry flower bud. Kinetics of drying, color indices and total phenol were determined in three replications and compared for the sixth drying methods. Results showed that the highest intensity of drying was occurred in cabinet dryer (60 oC) and the lowest was occurred in freeze dryer. The phenol reduction percentage buds which dried in cabinet dryer (40, 50, 60 oC), solar dryer and freeze dryer were respectively, 12, 17, 21.7, 26 in comparison with control (Shade drying). The maximum color index (L*) in the inner and outer petals of dried buds was observed in freeze dryer. This index in the inner and outer petals of dried buds which dried in cabinet dryer (50 oC) was 5 and 1.93 percents less than petals which dried in cabinet dryer (60 oC). The prolongation of drying process was caused to decrease the brightness of petals. The maximum value of a* index (25.61) was in the outer petal buds which dried in cabinet dryer (50 oC). The b* index in the outer and inner petal bud that dried in cabinet dryer (50 oC), solar dryers and in shade did not have significant difference.
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