Influence of Processing Methods on Okra (Abelmoschus Esculentus) Mucilage Content, Physicochemical Properties, and Antioxidant Activity

Yap, Carolyne Kar Ying (2026) Influence of Processing Methods on Okra (Abelmoschus Esculentus) Mucilage Content, Physicochemical Properties, and Antioxidant Activity. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

Okra (Abelmoschus esculentus) is recognized for its high mucilage content, which contributes to its characteristic viscosity and functional properties. This study investigated the influence of boiling (100°C, 20 min), roasting (160°C, 20 min), salting (2% NaCl), and acidification (0.001 M HCl) on okra mucilage content, physicochemical properties and antioxidant activity, using fresh okra as a control. Physicochemical properties including pH, moisture content, color and texture profile analysis (TPA) were evaluated. Samples were then dried at 40°C and milled into powder for extraction of mucilage using hot water and ethanol to determine yield, viscosity and water-soluble polysaccharide (WSP) content. Methanolic extracts were prepared from the powder to analyze the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activities (DPPH and FRAP). Results showed that boiling significantly increased (p < 0.05) moisture content while reducing textural properties such as hardness, gumminess, and chewiness. It also resulted in the highest mucilage yield, whereas roasting produced a comparatively high yield. However, both boiling and roasting caused reduction in mucilage viscosity, where roasting producing the lowest mucilage viscosity (92.00 mPa·s). In contrast, acidification preserved viscosity more effectively (225.00 mPa·s). All processing methods significantly reduced (p < 0.05) in TPC, TFC, DPPH and FRAP activities, while the salt treatment was the only method that significantly increased the TPC. Correlation analysis revealed a significant negative correlation between mucilage yield and viscosity (r = −0.625), showing a trade-off extraction efficiency and functional quality. Furthermore, DPPH scavenging activity correlated strongly with TFC (r = 0.836). Overall, thermal processing enhances mucilage yield but compromises structural integrity and antioxidant potential, likely due to polysaccharide depolymerization and phenolic degradation. Among the processed samples, boiling enhances extraction, the acidification preserves mucilage quality by yielding the highest viscosity, while salting retains the highest antioxidant activity.