Structural, chemical, and functional properties in breadfruit ( <i>Artocarpus altilis</i> ) flour induced by single and combined heat-moisture and lactic acid fermentation treatments

Breadfruit (Artocarpus altilis) flour is a promising substitute to wheat flour; however, its native form exhibits low swelling capacity, high gelatinization temperature, and rapid retrogradation. This study examined the effects of heat – moisture treatment (HMT), fermentation with Lactobacillus plantarum, and their combination on the physicochemical and functional properties of breadfruit flour. HMT was performed at 100°C for 16 h (30% moisture), and fermentation was carried out at 37°C for 24 h. Fermentation significantly enhanced viscosity with peak and final apparent viscosities increasing by 36–41% and 16–18%, respectively. Additionally, fermentation increased the swelling volume by 15–22%, while syneresis decreased by 23–35%. In contrast, HMT and combined HMT – fermentation reduced viscosity by more than 99% and swelling by 39–45%, but increased solubility by 81%, suggesting structural compaction and limited hydration. The gel hardness of the fermented flour decreased by 83–84% compared with the native flour, whereas HMT-treated flours exhibited no gel formation. Color analysis showed a slight increase in whiteness (~2%) following fermentation but a 22% reduction in lightness after HMT, mainly due to Maillard browning. All treatments maintained the native B-type crystalline pattern without introducing new functional groups. Overall, fermentation produced the most favorable functional properties, enhancing viscosity, swelling, and freeze – thaw stability, while HMT yielded thermally stable but less functional flour. These findings demonstrate that fermentation and combined modification effectively enhance the physicochemical versatility of breadfruit flour, broadening its potential application in bakery, gluten-free, and thickened food formulations.