Monthly variation in the chemical composition of Eisenia arborea J.E. Areschoug

The brown alga Eisenia arborea is the second most abundant brown alga along the western coast of the Baja California Peninsula of Mexico. Samples of E. arborea were collected in Bahía Asunción, BCS, over 10 months. Chemical composition was analyzed from dried alga (%, dw): moisture (10.34%), protein (9.44%), ash (24.77%), lipids (0.60%), fiber (5.22%), and carbohydrates (49%). Gross energy was 9.8 kJ g^-1. Seven minerals were analyzed and the four most abundant were K, Na, Mg, and Ca, ranging from 907 to 7,946 mg.100 g^-1. The concentrations of six vitamin levels were also determined: A, C, E, D_3, B₂, and B₁. Seventeen amino acids were analyzed and the most abundant were glutamic acid, aspartic acid, and leucine. Total fatty acids ranged from 21 to 65 mg.100 g^-1 (dw). Individual concentrations were also determined for arachidonic acid, alpha linolenic acid, linoleic acid, eicosapentaenoic acid, and docosahexaenoic acid. Saponins, cyanogenic glycosides, and alkaloids were not detected. Our results suggest that E. arborea is a good candidate to be tested as supplement food for animals, including humans. It contains essential amino acids, is low in lipids and fiber, and could be a source of vitamins and minerals.