Extraction and Comparative Characterization of Starch from Seed Kernels of Two Mango Varieties in Rajshahi

Mango seed kernels represent an underused agro-waste stream with potential as a sustainable starch source. This study compares starch extracted from two Bangladeshi cultivars, Mangifera indica ‘Gopalbhog’ and ‘Fazli’, to elucidate varietal effects on yield and physicochemical behavior. Mature fruits (10 kg per cultivar) were treated; kernels were preconditioned in 0.5% (w/v) sodium bisulfite (1:2 kernel:solution) for 24 h at 4 °C, wet-milled (800 rpm, 10 min), screened (100 mesh), and the starch separated by cold settling (12 h, 4 °C). Drying was performed at 70 °C for 36 h. Structural and functional properties were quantitatively characterized through FTIR (4000–500 cm⁻¹), UV–Vis (200–1400 nm), and gravimetric water absorption capacity (WAC) analyses to establish structure–function relationships between the cultivars. Starch yields were 25.2% (‘Gopalbhog’) and 20.8% (‘Fazli’), while WAC values were 152.2% and 146%, respectively. FTIR crystallinity indices (A₁₀₄₇/A₁₀₂₂) were 0.77 (‘Gopalbhog’) and 0.75 (‘Fazli’), indicating slightly greater short-range order in ‘Gopalbhog’. UV–Vis λmax values were 211 nm (A = 1.122) and 213 nm (A = 0.532). The higher order of ‘Gopalbhog’ reflects reduced hydratability, whereas ‘Fazli’s higher swelling suggests complementary applications in films, coatings, and hydrogels.