Nutrient composition and antioxidant activity of gonads of sea urchin Stomopneustes variolaris

•Nutritional composition of the species reported first time in Visakhapatnam coast.•Alternative source for PUFA and natural anti-oxidants.•Potential candidate for nutraceutical industry.•Gonads of S. variolaris were rich in essential amino acids.•Gonads of S. variolaris were rich in ω-3 fatty acids. The study investigated, for the first time, proximate nutritional composition and antioxidant activity of gonads from the sea urchin, Stomopneustes variolaris, inhabiting the coastal area of Visakhapatnam (India). Moisture, ash, proteins, lipids and carbohydrate content were 77.53%±0.80, 3.76%±0.25, 12.10%±0.41, 4.98%±0.36 and 1.63%±0.18, respectively, based on dry weight. The gonads were rich in essential amino acids (ca. 32.1% of total amino acids) with the most predominant being phenylalanine, lysine and valine. The essential to non-essential amino acid ratio was 0.5. Polyunsaturated fatty acids (PUFA) constituted 22.01%±2.2 of total fatty acids. The ω6:ω3 ratio was 0.94. Total phenol content of the gonad was 9.90±0.01mg GAE/g and the IC50 of the extract, using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, was 57.81μg/ml.