Zuhriyan Ash Shiddieqy Bahlawan, Satriyo Krido Wahono, Megawati, Ria Desiriani, Maulida Zakia, Indrasukma Permanadewi, Agung Kurnia Yahya, Achmad Yanuar Maulana, Andri Cahyo Kumoro
Solid-state fermentation using Rhizopus oligosporus offers a promising strategy to improve the nutritional and functional quality of sorghum flour. This study investigated the effects of varying inoculum concentrations (1–4%, v/w) on the physicochemical, structural, and functional properties of sorghum flour during 48 h of fermentation. The results demonstrated a significant reduction in extractable condensed tannin content, with a maximum decrease of approximately 79.07%. Fermentation was also associated with an increase in protein content from 7.01% to 8.12%, enhanced DPPH radical scavenging capacity, and increases in total phenolic acid- and flavonoid-related parameters. Functional properties were also modified, characterized by reduced water solubility index (WSI) and viscosity, while water absorption index (WAI) and swelling power (SP) remained relatively stable. Structural analyses using FTIR and SEM indicated fermentation-associated modifications in the sorghum flour matrix, accompanied by progressive microstructural changes that may influence molecular accessibility. In addition, fermentation induced measurable color changes, characterized by increased lightness (L*) and a shift toward yellowish hues, which may be associated with changes in phenolic-related compounds during fermentation. Overall, the results demonstrate that R. oligosporus fermentation is associated with compositional, structural, and functional changes in sorghum flour. These findings highlight the potential of controlled fungal fermentation as an approach to develop sorghum-based ingredients with modified nutritional and functional characteristics. © 2026 The Authors.
Department of Chemical Engineering, Universitas Negeri Semarang, Semarang, 50229, Indonesia; Food Technology and Bioprocess Laboratory, Universitas Negeri Semarang, Faculty of Engineering, Semarang, Indonesia; Research Center for Food Technology and Processing - National Research and Innovation Agency Republic of Indonesia (PRTPP - BRIN), Yogyakarta, 55861, Indonesia; Research Center of Nanotechnology Systems, National Research and Innovation Agency (BRIN), South Tangerang, 15314, Indonesia; Department of Chemical Engineering, Politeknik ATI Padang, Padang, 25171, Indonesia; DAU G-LAMP Project Group, Institute of Natural Science, Dong-A University, Busan, 49315, South Korea; Department of Chemistry, Dong-A University, Busan, 49315, South Korea; Department of Chemical Engineering, Faculty of Engineering, Universitas Diponegoro, Semarang, 50275, Indonesia
