Kaffir Lime Leaf (Citrus hystricDC.) Drying Using Tray and Heat Pump Dehumidified Drying

Abstract

Desorption isotherms of mature kaffir lime leaves are determined and a nonlinear regression program was applied to the experimental data to fit with any of the four moisture sorption isotherm models. It was found that the modified Halsey model could fit the best. Tray and heat pump-dehumidified drying of kaffir lime leaves were conducted and it was found that the modified Page model was the most effective one. The drying constant was fitted to drying air temperature using the Arrhenius model. Effective moisture diffusivities were determined using the drying data. Heat pump-dehumidified drying reduced drying time and provided dried kaffir lime leaves with higher amount of citronellal than tray drying.

Microwave blanching and drying characteristics of Centella asiatica (L.) urban leaves using tray and heat pump-assisted dehumidified drying

“…The results agreed with the previous research (Phoungchandang et al 2003;2009;Phoungchandang and Saentaweesuk 2011). The exponent (N) was added to drying constant and drying time of the NT model to increase the dependence of temperature and relative humidity of the drying air (Phoungchandang 2008;Phoungchandang et al 2008a, b;2009). The K values increasing with temperature obtained from HPD were higher than that from TD because of the lower RH of drying air at the same drying temperature (Table 5).…”

“…(17) and Table 5). They were determined by fitting the experimental data in terms of ln(MR) versus t (Chottanom and Phoungchandang 2005;Phoungchandang et al 2008a, b;2009;Potisate and Phoungchandang 2010). The results revealed that microwave blanching and higher drying temperature provided higher D eff in both TD and HPD.…”

“…However, various types of products have been dried in experimental heat pump dehumidified dryers. Dried products include biomaterials (Alves-Filho and Strommen 1996), sawn rubber wood and bananas (Prasertsan and Saen-saby 1998), banana (Chua et al 2001), holy basil leaves (Phoungchandang et al 2003), garlic (Boonnattakorn et al 2004), mangoes (Chottanom and Phoungchandang 2005), ginger (Hawlader et al 2006;Phoungchandang et al 2009;Phoungchandang and Saentaweesuk 2011), composite food products (Rahman et al 2007), red pepper (Alves-Filho et al 2007), protein (AlvesFilho et al 2008), kaffir lime leaves (Phoungchandang et al 2008a), white mulberry leaves (Phoungchandang et al 2008b) and ivy gourd leaves (Potisate and Phoungchandang 2010).…”

“…The results revealed that microwave blanched C. asiatica leaves dried in HPD at 40 to 50°C contained the highest total phenolics and at 40°C increased % inhibition by 6.1 % ( Table 6). The microwave blanching and HPD provided the highest total TD tray dryer and HPD heat pump-assisted dehumidified dryer (n03) phenolics and % inhibition due to short drying time and also low drying temperature (Table 5) (Phoungchandang et al 2003;Phoungchandang et al 2008a;2009).…”

“…In this work, the general approaches of Sun and Woods (1994) for wheat, Phoungchandang et al (2008a) for kaffir lime leaves and Phoungchandang et al (2008b) for white mulberry leaves were adopted and developed from the review of isotherm determination in Sun and Woods (1993) for wheat. This involved fitting 4 well-established forms for the sorption model to the desorption data for C. asiatica leaves in order to establish the best fit.…”