An edible red seaweed (Pyropia orbicularis): influence of vacuum drying on physicochemical composition, bioactive compounds, antioxidant capacity, and pigments

Drying kinetics, proximate composition, dietary fiber, total phenolic compounds, pigments, amino acid profile, and antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity) of a red edible seaweed (Pyropia orbicularis) subjected to vacuum drying at five temperatures (40-80 A degrees C) were evaluated. The experimental drying curves were satisfactorily fitted to the Weibull model. The total dietary fiber (TDF) of this seaweed presented a value of 64.37 g (100 g)(-1) d.m. The ratio IDF:TDF was 81.1%. The values for protein ranged between 22.34 and 24.92 g (100 g)(-1) d.m. in dried seaweed, and His, Thr, and Pro were the most abundant amino acids. The chlorophyll a content was higher than that for chlorophyll b. Total phenolic content (TPC), phycoerythrin and phycocyanin contents, and carotenoid content as well as antioxidant capacity showed an increase at 70 A degrees C. Moreover, at 70 A degrees C, Delta E presented a value of 15.66. Correlations between the TPC and DPPH values (r (2) = 0.899) as well as lightness and hue angle (r (2) = 0.776) were found during food drying. This work provides important information about the chemical composition and nutraceutical properties of the Chilean edible red seaweed, P. orbicularis.