Effect of different post-harvest treatments on free amino acid content in Fucus vesiculosus

The effect of different post-harvest treatments (fresh, freezing and air- drying) and storage duration on free amino acid (FAA) content of brown seaweed Fucus vesiculosus were studied. The FAA profile of thalli algae was studied every 3 months over 1 year. The FAA were extracted in ethanol/water (70: 30) solution, purified by ion exchange chromatography, derivatized and determined using hight-performance liquid chromatography. Free amino acid profile was significantly (p<0.001) different among the fresh, freezing and air-drying seaweeds. Long-term storage of seaweeds for 12 months in both dried and frozen form contributed to increased levels of free amino acids. The total free amino acid content increased from 285.80 mg/100 g dry matter of fresh seaweeds to 597.38 mg/100 g dry matter of dried seaweeds and to 473.84 mg/100 g dry matter of the frozen form. The total content of essential amino acids increased from 49.65 mg/100 g dry matter in fresh seaweeds to 130.45 mg/100 g dry matter of dried seaweeds and to 106.70 mg/100 g dry matter of frozen seaweeds. The content of glutamic acid responsible for the taste increased from 132.36 mg/100 g dry matter of fresh seaweeds to 169.50 mg/100 g dry matter of dried seaweeds, and to 242.00 mg/100 g dry matter of frozen seaweeds. Thus, the long-term storage of dried and frozen seaweeds contributes to the improvement of their qualities.