| Abstract: | Lima bean (Phaseolus lunatus) starch was modified using pyroconversion to produce non‐digestible starch and the functional properties of the pyrodextrinized starches were evaluated. Reaction conditions included: starch/2.2 M HCl ratio (80:1 and 160:1, w/v); temperature (90°C and 110°C) and reaction time (1 and 3 h). “In vitro” indigestible starch and color difference (ΔE) were determined and used as response variables. The optimum product was recovered from native starch treated with a 160:1 starch/HCl ratio, at 90°C for 1 h, which produced modified starches containing 49.5% indigestible starch and ΔE of 18.86. Starch pyrodextrinization decreased the amount of enzymatically available starch through formation of atypical glycosidic bonds that are not digested by the amylases and maltooligosaccharidases in the small intestine of humans. Compared to the P. lunatus native starch, the pyrodextrinized starch exhibited increased paste and gel clarity (52.7%T), solubility (88.7%), and swelling power (26 g water/g starch), a higher gelatinization temperature range (72.5–89.8°C) and lower viscosity. This process can be considered a promising treatment for production of resistant starch (RS) from P. lunatus. |
