Color, chlorophyll, caffeine, and water content variation during yerba mate processing

The objective of this research was the determination of color (L, a and b values, hue, chroma and DeltaE), chlorophylls, caffeine and water contest variation during industrial processing of yerba mate (Ilex pm paraguariensis Saint Hillarie). For leaves, the greatest variation in color, total chlorophyll concentration (> 80%) and water content (approximately 70%) was found during blanching, operation performed with hot gases at temperatures above 500 degreesC. On the contrary, caffeine loss (about 20%) ill leaves mainly occurred during hot air drying, carried out in two stages, with inlet air temperatures about 110 degreesC. Moisture content variation in twigs were more important in the drying steps, the values being strongly dependent on twig diameter.