Characterization of Sago Starch Complex with Ferulic Acid Isolated from Corn Cob and Evaluation of Antioxidant Activity
ABSTRACT. Corncob is one of agro-food by-products, a potential source of natural antioxidants and functional food ingredients, rich in ferulic acid and dietary fibre. In this study, ferulic acid was isolated from corncobs after alkaline pretreatment using a multi-step extraction process and structurally verified, providing a suitable bioactive compound for baruk sago (SB) starch complexation. FTIR analysis showed characteristic absorption peaks at 3379-3387 cm⁻¹, indicating interactions between FA and starch. XRD results revealed a transformation of the native SB starch crystalline structure and a marked decrease in crystallinity from 40.31% to 8.60% after complexation. SEM observations demonstrated morphological changes from predominantly smooth, oval, and compact granules to a looser gel structure in the starch–FA complex. In vitro antioxidant evaluation using the DPPH radical scavenging assay showed that the SB starch–FA complex exhibited higher scavenging activity compared to native SB and pre-gelatinized (SBG) starch. These findings confirm the successful incorporation of FA into SB starch and demonstrate that complexation significantly modifies physicochemical properties and enhances antioxidant capacity, highlighting its potential application as a functional food ingredient and nutraceutical material. Keywords: Antioxidant, characterization, sagu baruk, starch-ferulic acid complex