PHYSIOCHEMICAL, BIOCHEMICAL AND PHYTOCHEMICAL PROFILING OF SODIUM ALGINATE AND ITS ROLE AS A SEED COATING POLYMER TO ENHANCING SEED QUALITY IN OKRA (ABELMOSCHUS ESCULENTUS)

Abstract

Sodium alginate, a naturally occurring polysaccharide extracted from brown marine algae, has emerged as a promising biopolymer for sustainable agricultural applications. This study investigated the extraction, characterization, and functional evaluation of sodium alginate derived from Sargassummyriocystum and assessed its potential as a biodegradable seed-coating polymer for improving seed quality traits in okra (Abelmoschusesculentus L.). The extraction yielded 25% sodium alginate. Physicochemical characterization revealed medium viscosity (90 cP), an alkaline pH (7.20), a blackish-brown colour, and high water-absorption capacity. Biochemical analysis indicated a high carbohydrate content (70%) with negligible protein and lipid fractions, while phytochemical screening detected only saponins, indicating high purity. ICP–MS analysis revealed a high sodium content (200,000 ppm), confirming the sodium alginate form, and FTIR analysis verified the structural integrity and purity of the extracted alginate through characteristic O–H and C=O absorption bands with high transmittance (>95%). The extracted alginate was infused with selected biomolecules and applied as a seed-coating polymer. Among the treatments, T14 exhibited the best performance, recording 96% germination, 40.58 cm seedling growth, 0.463 g dry matter production per 10 seedlings, higher vigour indices I and II, and only 2% abnormal seedlings. In contrast, the uncoated control (T0) showed the lowest germination (86%), seedling growth (30.34 cm), dry matter production (0.343 g per 10 seedlings), vigour indices, and the highest proportion of abnormal seedlings (9%). These findings demonstrate that sodium alginate derived from S. myriocystum is an effective, eco-friendly alternative to synthetic polymer and microplastic-based seed coatings. As a natural hydrocolloid, it significantly enhances seed quality attributes and holds considerable promise for sustainable and environmentally responsible agricultural practices.