Drying and extraction process of lemongrass ("Cymbopogon citratus")

Lemongrass (Cymbopogon citratus) is one of the most used plants in Mexico folk medicine for treating nervous and gastrointestinal disturbances. Tray drying is an efficient alternative to preserve perishable food as lemongrass; however, the choice of drying conditions is determinant in order to provide plants with better quality after harvesting. The objective of this study was to show the effect of different drying conditions on the performance of extracts and quality attributes of extract of C. citratus. A randomized experimental design 3(2) with three replications was used, the factors studied were surface areas (2, 4 and 6 cm(2)) and drying air temperature (40, 60 and 80 degrees C), the experimental unit was lemongrass leaves with a length of 60 +/- 3 cm, and he results were analyzed using ANOVA (p <= 0.05). The results indicated that the drying kinetics of lemongrass were affected (p <= 0.05) by the air temperature and surface area during drying, while color parameters (L, Hue, Chroma, DE) increased with drying time. As size increase from 2 to 6 cm(2), luminosity of lemongrass samples increased slightly, whereas Hue and Chroma value increased for all temperatures. However, the greatest color difference (from 5.2 to 6.9) was observed in dehydrated lemongrass samples at 40 degrees C. The statistical analysis of drying results showed significant effect (p <= 0.05) on extraction degree of lemongrass. The extract color and pH were influenced significantly (p <= 0.05) by solvent and sample type of extraction process. The experimental values of the antioxidant activity (DPPH method) were 87.29 % and 63.6 % for the aqueous and ethanolic extract, respectively. Moreover, the lemongrass extract had no significant antimicrobial effect on yeast (Saccharomyces cerevisiae).