Characterization and digestogram modeling of modified elephant foot yam (Amorphophallus paeoniifolius) starch using ultrasonic pretreated autoclaving

Abstract Native elephant foot yam starch (EFYS) is highly digestible, and it is not recommendable for consumption by diabetic and obese people. To address this problem, the current study focuses on the amendments in various properties (such as functional properties, whiteness index, amylose content, morphology, and digestion) of EFYS using ultrasonication (US) and US pretreated autoclave (AL) modification with varied time viz. 15, 30, and 45 min. Both the treatments enhanced the water absorption, swelling power, and solubility of EFYS. US‐assisted AL treatment was responsible for increasing the resistant starch (RS) fraction and the highest increment was observed in US‐AL45 EFYS (39.13 ± 1.19 %) as compared to the native counterpart (30.65 ± 1.06 %). Molecular aggregations were observed in all US‐AL EFYS, whereas US treatment broke the agglomerations and increased the intergranular spaces. FTIR analysis revealed the highest increase in ordered to amorphous starch (1047/1022 cm −1 ) in US‐AL45 EFYS followed by native and others modified EFYS. The highest increase in amylose content was notable in US‐AL45 (10.02 ± 0.08 %) as compared to other native and others treated EFYS. To understand the kinetic behavior of the native and modified EFYS, first‐order kinetics, Michaelis–Menten, Paolucci Jeanjean, Logistic, and Weibull models were applied. The digestogram models highlighted the highest digestibility in native EFYS, preceded by US, US‐AL 15, US‐AL 30, and US‐AL 45 EFYS. US‐AL 45 EFYS showed the highest change in all the functional properties as compared to native and other modified EFYS. Practical applications Owing to the prevalent lifestyle diseases, a continuous evolution in nutritional behaviors has emerged. Although starch imparts consistency and quality to the commercial food products, its high digestibility results in harmful effects to diabetic and obese patients. Elephant foot yam is considered as a unique source of starch and its modification leads to a decrease in enzyme hydrolysis while making it health beneficial. Ultrasonic pretreated autoclaving is one such potential physical modification treatment which can facilitate toward decrease in enzyme digestibility of elephant foot yam starch (EFYS), yet enhancing its swelling properties that in turn leads to the growth of functional food processing industry. The findings of the study highlight the enzyme digestogram modeling of US and US‐AL modified EFYS in order to shed light on the mechanism that regulates them.