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.

Phytochemical components and amino acid profile of brown seaweed Durvillaea antarctica as affected by air drying temperature

“…During drying at all temperatures between 40 and 80°C, a significant degradation of the chlorophyll pigments was observed with a minimum level of 59% of the initial chlorophyll content occurring at 60°C, while the least degradation occurred at 50°C with an average retention of 87%. It was also observed in a previous work (Uribe et al 2017) that the final dried products at these two temperatures had no-significantly different water contents (9%) with respect to fresh weight, but moisture diffusivities were 1.42 9 10 -9 m 2 /s at 60°C being higher than that at 50°C (1.04 9 10 -9 m 2 /s). Consequently, a moisture ratio of around 0.1 was achieved in 120 and 240 min at 60 and 50°C respectively, indicating for a similar moisture loss preponderance of drying temperature over drying time.…”

“…Drying temperature between 40 and 80°C (Table 1) showed in general no significant influence on dietary fibre content, except for an observed significant drop in SDF at 70°C, which could be occurring within a critical temperature range where the soluble dietary fibres could be more vulnerable to chemical destruction due to prolonged drying at a relatively high temperature. Drying time to achieve equilibrium moisture content at 70°C was around 220 min that was nearer to the corresponding drying time at 60°C (240 min) than to that at 80°C that was around 170 min (Uribe et al 2017).…”

“…In the Chilean coast, it can be found from Coquimbo to Cape Horn (Mansilla et al 2012). It can measure up to 15 m and has a dark greenish-brown or yellowish-brown colour, consisting of two parts: the fronds of the plant called cochayuyo or chamisso, with a typical width between 3 and 12 cm, and the stem (known as hulte) that is usually consumed as a fresh product (Uribe et al 2017). As reported by Chile Central Bank in 2015, an average of 2000 tons of cochayuyo has been exported annually between 2010 and mid-2015, with a peak in FOB value of 5,261,665 US$ in 2014.…”

Hybrid solar dryer for sugar‐palm vermicelli drying

“…Accordingly, the results indicate that there is an increase in fat and protein content when processing the sugar-palm starch into dry vermicelli. This is because, during the drying process, there is significant moisture removal, which increases the concentration of other nutrients (Uribe et al, 2017). Therefore, hybrid solar drying is able to increase the content of other nutrients in addition to reducing the moisture content of vermicelli.…”

Equilibrium Moisture and Drying Kinetics Modelling of Macroalgae Species Ulva ohnoi and Oedogonium intermedium

“…Many studies in the literature have used diffusion modelling approaches to successfully represent macroalgae drying [15][16][17][18][19]. Other drying studies utilising diffusion-based modelling of algae include several covering the drying kinetics of the microalga Arthrospira platensis (Cyanobacteria) [20,21].…”