Influence of Physical, Chemical, Enzymatic, and Fermentation Modifications on the Physicochemical Characteristics and Microstructure of Jack Bean (Canavalia ensiformis) Flour

Jack bean (Canavalia ensiformis) is a protein- and carbohydrate-rich legume with limited food application due to poor physicochemical properties and beany flavour. This study examined the effects of physical, chemical, enzymatic, and fermentation modifications on the functional and structural characteristics of jack bean flour. Treatments included autoclaving–cooling (one and two cycles), annealing, microwave–cooling, heat moisture treatment, acid hydrolysis, pullulanase debranching, and combined fermentation–autoclaving. Modified and native flours were evaluated for colour, pasting properties, starch digestibility, and microstructure using scanning electron microscopy (SEM). The modifications significantly influenced flour characteristics, with pullulanase debranching (DP) showing the most desirable attributes: higher peak viscosity (11.50 cP), lower setback viscosity (3.50 cP), and reduced starch digestibility (33.02%). SEM images revealed disrupted and porous granule structures, especially in enzymatically and fermentatively modified samples. Overall, the modification treatments enhanced thermal stability, reduced retrogradation, and improved the functional potential of jack bean flour. These findings highlight its suitability for use in functional foods, bakery formulations, and plant-based ingredients, supporting industrial applications in starch-based product innovation.