Moth bean (Vigna aconitifolia) starch is modified in its dry state (110 °C for 8 h, 14% moisture) using various ratios of organic acids (citric acid and stearic acid) in solvent free (solid–solid) reaction mode. Apparent amylose content is observed to increase in organic acid treated starches. Modified starches show lower swelling power than native starch. Scanning electron micrographs display rough granules surface for treated starches. Crystalline polymorphic pattern of moth bean starch is unaffected by organic acid treatment and dry heating. However, relative crystallinity increases after dry modification. Pasting properties indicate reduction following hydrolysis and loss of granular strength. Resistant starch (RS) content increases as an effect of the modification. This novel modification provides different functionality as compared to aqueous protocols and also provides a clean alternative to replace acid hydrolysis process with concentrated mineral acids.