Effect of Drying on the Color of Tarragon (Artemisia dracunculus L.) Leaves

Abstract

The effect of drying conditions on the color of tarragon (Artemisia dracunculus L.) leaves was studied. Tarragon leaves were dried at temperatures of 40 to 90°C with a constant airflow of 0.6 m/s. The samples were collected at 7%, 10%, 20%, and 30% moisture content wet basis for evaluation of the color change. The color parameters of fresh and dried leaves were measured by a colorimeter. The individual parameters of L*a*b* and L*C*h°color systems were evaluated and h°proved to be the best parameter to monitor color change. The smallest change of the color parameters was observed at 40°C, in which temperature was low, and also at 90°C, when drying time was short. The biggest change occurred at the temperatures of 50 to 70°C. Most of the color change happened before the material reaches 35% moisture content. The combination of drying time and temperature defines the change of color.

Evaluation of seven different drying treatments in respect to total flavonoid, phenolic, vitamin C content, chlorophyll, antioxidant activity and color of green tea (Camellia sinensis or C. assamica) leaves

“…The L* value of freeze drying treatment was the highest among all dried leaves (25.2), while sun drying revealed the lowest L* (20.1) value among dried treatments (P<0.05). High temperature and long drying time is the most effective factors in color damage during drying (Arslan and Ozcan 2008;Arabhosseini et al 2011;Rahimmalek and Goli 2013). Similar results were also obtained for b*( Table 1).…”

Effect of Drying Method on Sensory Characteristics and Essential Oil Composition of Thyme ( Thymus Vulgaris L.)

“…Ziele suszone w warunkach naturalnych zawierało znaczny udział barwy żółtozielonej i żółtooliwkowej, co, jak podaje Arabhosseini i wsp. [4], może wynikać z rozkładu chlorofilu na skutek długiego czasu trwania tego procesu.…”

Heat pump assisted drying of agricultural produce—an overview

“…loss of vitamin C, and changes of colour (Arabhosseini et al 2010) and appearance that might not be desirable. For example, air-drying is the most common method in the drying of foodstuffs but this method leads to serious injuries such as the worsening of the taste, colour and nutritional content of the product, decline in the density and water absorbance capacity and shifting of the solutes from the internal part of the drying material to the surface, due to the long drying period and high temperature (Yongsawatdigul and Gunasekaran 1996;Lin et al 1998;Maskan 2001).…”