Evaluating the nutraceutical and antioxidative potential of alginate beads entrapped marine diatoms

Abstract

Diatoms are a rich source of diverse bioactive compounds, suggesting substantial nutraceutical and biotechnological potential. The present study evaluates and compares a detailed biochemical and metabolic assessment, including protein, carbohydrate, phenolic content, chrysolaminarin, flavonoids, pigments, total lipid, biodiesel, polysaccharide estimation, and various antioxidative enzyme assays, within the entrapped alginate beads (referred to as 1) three different marine diatom species: Chaetoceros gracilis, Thalassiosira weissflogii, and Cylindrotheca sp. versus their free-cell counterparts (referred as 2). Fatty acid profiling revealed that CY2 has a high content of PUFAs at 42.91 %, with EPA constituting 31.03 %. Additionally, T2 exhibited the highest DHA content at 0.733 %. Biochemical assessment demonstrated that T2 has the highest protein content (127.34 ± 0.15 mg g^-1) and CY1 has the highest chrysolaminarin content (163.97± 1.71mg g^-1), while CY2 exhibits the highest carbohydrate content at 6.90± 0.21 mg g^-1. In this study, fucoxanthin was highest in T2 (4.34 ± 0.12 mg g^-1) and carotenoids were highest in CY1 (27.01 ± 1.50 mg g^-1 respectively). DPPH was highest in C1 (51.85 TE g DW ^-1), while ABTS activity was maximum in T1 (158.83 TE g DW⁻¹). Sustaining a balanced intake of n-6 and n-3 PUFAs is crucial for maintaining nutritional value. In the present study lipid nutritional quality shows CY2 has the lowest AI and TI values followed by T2 which contribute to various health benefits. Overall, the findings demonstrate that immobilized diatoms, which are eco-friendly and reusable, can serve as sustainable sources of essential nutrients and antioxidants. This research paves the way for their application in human health and fosters a more sustainable and circular economy within the nutraceutical sector, highlighting their potential to enhance food security, improve health outcomes, and promote environmentally friendly practices in the industry.