Physicochemical, Morphological, and Pasting Diversity of Native Sago Starch Samples from Seventeen Indonesian Regions

Sago is an important tropical crop that provides important benefits to humans because of its high starch content. Sago starch varies in structure and function depending on its origin. However, data regarding the physical, structural, viscosity, and functional properties of native Indonesian sago starch from diverse geographical sources remain limited. This study aimed to characterize the physical, structural, and pasting properties of local Indonesian sago starch. Physical analysis revealed a bright color (L* values of 75.54–91.95), positive a* values (0.60–6.03) indicating redness, and positive b* values (2.57–18.57) indicating yellowness. SEM analysis showed sago starch granules ranging from oval to elliptical, with average diameters of 22.23–35.30 μm; larger granules were associated with greater swelling and higher viscosity. Pasting properties (RVA) revealed significant differences in peak viscosity, ranging from 1028 to 5057 cP. Based on pasting behavior, sago starch samples from different origins were categorized into five clusters. Cluster 1 (Lingga, Luwu, Sentani) showed high swelling, low thermal stability, and high retrogradation. Cluster 2 (Tembilahan, Pontianak) exhibited low swelling and high granular stability. Cluster 3 (Timika) was prone to disintegration but formed a rigid gel. Cluster 4 (Indragiri Hilir, Banjarmasin, Banda Aceh, Halmahera, Mamuju, Kendari, Central Moluccas, East Luwu, Meranti) displayed an intermediate profile with distinct degradation. Cluster 5 (North Luwu and Biak) showed low to moderate viscosity and retrogradation. FTIR spectra indicated that the sago starch retained its native structure. Integrated analysis suggests that native Indonesian sago starch samples from various geographical regions exhibit substantial variation in physicochemical and functional properties. These structural and functional properties provide a preliminary basis for evaluating the potential uses of the starch in region-specific food and industrial applications.