Ultrasound and gamma-irradiation assisted development of starch-fatty acid complex: Impact of palmitic acid and stearic acid on structural, functional properties of Corypha umbraculifera L. starch

The aim of this study was to investigate the influence of pretreatments, such as irradiation or ultrasonication, on the formation of complexes between talipot starch and fatty acids (FA), alongside an analysis of changes in the structure, functional properties, and in vitro digestibility of starch-FA complexes. Two different fatty acids, palmitic acid (C16:0) and stearic acid (C18:0) were considered. Ultrasonicated starch exhibited a higher complexing index (CI) than both native and irradiated samples. The FTIR spectra of the FA-complexed starches revealed new peaks at 2843 cm −1 and 1707 cm −1 , indicative of carbonyl and symmetric stretching of the CH 2 and CH 3 groups of the FAs, respectively, which confirmed the starch-FA complex formation. The complexing of FA significantly reduced the swelling index of talipot starch. Among tested FA-complexed starches, native starch complexed with palmitic acid had the highest pasting profile. The crystallinity of FA-complexed starches changed from A-type to a mixture of A and V-type. The rheological analyses showed that FA-complexed starches had decreased storage and loss moduli. The gel hardness and paste clarity of talipot starch underwent substantial reduction with increasing CI, with the impact more pronounced in the case of pre-ultrasonicated samples. The FA complexing of talipot starch reduced digestibility while increasing resistant starch (RS) content. The pre-ultrasonicated starches exhibited notably higher RS content, reaching 58.77% and 59. 13% for palmitic and stearic acid-complexed talipot starch, respectively.