Comparative Efficacy of Brown Seaweed (Sargassum spp.) extract and Butylated Hydroxyanisole (BHA) on the Oxidative Stability of Dried Stolephorus delicatulus During Storage

The study evaluated the effectiveness of a natural antioxidant extracted from locally sourced brown seaweed, Sargassum spp., compared to the synthetic antioxidant Butylated Hydroxyanisole. Stolephorus delicatulus is highly susceptible to lipid oxidation during storage, leading to rancidity and financial losses for artisanal traders on the Kenyan South Coast. Despite its bioactive potential, Sargassum spp. remains underutilized locally, mainly serving as bait in traditional basket traps (Dema). This study explored a safer bio-based alternative to synthetic antioxidants, hypothesizing that phlorotannins in Sargassum spp. would provide comparable preservative effects to BHA due to their strong radical-scavenging properties.

The study was conducted at the Mwazaro fish processing site in Shimoni using climate-smart drying infrastructure. Bioactive compounds were extracted from Sargassum spp. through ethanol-water maceration and concentrated using a rotary vacuum evaporator at 40°C. Three sample groups - seaweed extract-treated, BHA-treated, and untreated control - were stored for three months under ambient conditions. Laboratory analyses at KMFRI evaluated Peroxide Value (PV), Thiobarbituric Acid Reactive Substances (TBARS), and Total Volatile Basic Nitrogen (TVB-N). Sensory quality was assessed using a 5-point hedonic scale by expert fish processors.

Data were analyzed in R using two-way ANOVA and Tukey’s HSD test at p < 0.05. Both Sargassum spp. extract and BHA significantly reduced PV, TBARS, and TVB-N increases compared to the control, with no significant differences between treatments. Sensory scores also showed better acceptability in treated samples. Overall, Sargassum spp. extract demonstrated strong potential as a sustainable natural antioxidant for preserving dried fish and reducing post-harvest losses in coastal fisheries.