Challenges in determining protein quantity and quality in four seaweed varieties

Given the growing population, the need for protein diversification, food security and efficient use of natural resources, seaweeds make a sustainable and favourable protein source, especially in the plant-based alternative protein sector.Seaweeds can grow in saline conditions and produce protein-rich biomass along with various bioactive components.Research available thus far has examined the overall nutritional profile of different seaweed species [1].Comparative studies exploring the differences in nutritional profiles, particularly the protein content and amino acid composition, within different commercially available species of seaweeds are rare.The present study investigates the variation in protein content and amino acid composition in four selected commercially available seaweeds namely, sea lettuce, kombu, wakame and nori from three different suppliers which are offered for human consumption.Variation in protein content by Kjeldahl method was observed between the four different species and within the three suppliers.The results from Kjeldahl revealed lower protein quantities in comparison to reference values even when seaweed species specific protein conversion factors were used for the estimation of protein content [2].Amino acids were determined after derivatizing the samples using the silylation reagent MTBSTFA by GC-MS.Both essential and non-essential amino acids were identified, and sea lettuce contained the highest content of essential amino acids.The findings of the present study confirm that seaweeds are a high-quality protein source with essential amino acids such as valine, leucine, isoleucine, methionine, threonine, and phenylalanine.