Drying characteristics and water desorption isotherm of Ulva spp. using different drying methods
Fecha
20182018
Institución
Resumen
Green algae belonging to the genera Ulva (Chlorophyta) are common seaweeds distributed
worldwi de. They possess an interesting nutritional composition making their commercial
exploitation attractive to produce functional food ingredients. However, to obtain a product
suitable for industrial processing it is necessary to control the preservation and drying
conditions. The aim of this work was to establish the effect of different drying methods on
drying characteristic, desorption Isotherms and color of green seaweeds genus Ulva from
Region of Coquimbo, Chile. Four different drying conditions were used: freeze-drying
for 390 min; sun
content was determined by a gravimetric technique. The surface color of the samples were
measured using a HunterLab colorimeter and the CIE L*, a* and b* colour scale. Drying
results showed that different drying methods had significant effects on the drying
characteristics and kinetics. The CD had the best drying characteristics with the shortest
drying time and the fastest drying rate. Monolayer moisture content evaluated by the BET
model corresponded to the moisture content at which local minimum integral entropy value
was observed for sorption processes. Brightness parameter (L*) of the product increased its
value independent of the applied drying method, where FD stood out due to its increase,
whereas the chromatic coordinates ( a* and b*) showed a different pattern, these values
decreased in all treatments compared to the control sample (p <0.05). This work provides
an important information about the drying characteristics by application of different drying
methods to the Chilean edible green seaweed, Ulva spp.
Keywords: Ulva spp., drying methods, water desorption isotherm, surface color