Nutritional composition and phenolic contents of Gracilariopsis longissima, Padina tetrastromatica and Ulva intestinalis from the Bay of Bengal, Bangladesh coast

Abstract

Seaweeds have become the focus of experts in recent years due to their biological characteristics and the variety of uses they have for both humans and animals. Biochemical composition, amino acids, fatty acids, and phenolic components were analyzed to explore the nutritive value of Gracilariopsis longissima, Padina tetrastromatica, and Ulva intestinalis from the Bay of Bengal, Bangladesh coast. Proximate composition and mineral content were determined according to the AOAC method. The high-performance liquid chromatography amino acid analysis system was used for the amino acid analysis and the fatty acid profile of the extracted oils was assessed as their methyl esters. The Folin–Ciocalteu technique was used to estimate the phenolic content and the aluminum chloride colorimetric technique was used to calculate the total flavonoid content. The three different species of seaweed had significantly different proximate compositions (P < 0.05), with G. longissima having the highest protein content. Except for sulfur, the mineral contents were likewise considerably higher (P < 0.05) in G. longissima. Although the amounts of the essential amino acids were greater than 50 % of the total amino acids in the three studied seaweed species, the total amino acid composition of these three species differed significantly (P < 0.05). The findings indicated that lipid levels were low in all the assessed species, but unsaturated fatty acid levels were high, with G. longissima exhibiting the highest amounts. The results showed that, compared to the other species, G. longissima had a substantially higher (P < 0.05) level of total phenolic and flavonoid content. The three studied seaweed appear to be excellent for nutrition based on their overall nutritional profiles. However, due to high protein, unsaturated fatty acid, essential amino acid, and total phenolic and flavonoid content, G. longissima is the most promising seaweed that will be helpful for pharmaceutical and multifunctional food applications.