Hot-air drying characteristics and energetic requirement of the edible brown seaweedDurvillaea antarctica

Abstract

The drying characteristics of edible seaweed Durvillaea antarctica subjected to hot-air drying at 40, 50, 60, 70, and 80°C were investigated. Desorption isotherm was performed to estimate the equilibrium moisture content. Ten mathematical models were applied on the drying kinetics. The effect of drying temperatures on the proximate composition in this seaweed was also evaluated. Drying process resulted in an apparent increase of the ash and crude protein contents as compared to fresh sample. Midilli-Kucuk model presented the best-fit quality on drying curves. An effective diffusional coefficient from 0.74 × 10−9 to 2.37 × 10−9 m2 s−1 was determined. At last, the energy consumption and efficiency value at 80°C were 13.54 kWh kg−1 and 34.57%, respectively. Furthermore, it is possible to estimate the hot-air drying conditions and obtain a dehydrated product as alternative to solar drying. Practical applications Durvillaea antarctica is a brown seaweed, which has proving to be very significant in terms of its nutritional value and bioactive compounds, which can benefit human health. For this reason, it is expected that its commercialization and consumption will increase strongly. Usually, D. antarctica requires of a drying process due to large amount of water that contain in its fresh state. Traditionally, it is dried under the sun but this operation can cause losses of material, degradation of nutritional values and poor quality on this seaweed. The use of a convective dryer with controlled conditions can be a good alternative to explore for this seaweed. Several mathematical modeling have been widely used for analysis of drying of various marine products such as seaweed to determine the best operation conditions and to understand the water transfer mechanisms from seaweed to surrounding air.