Improving resistant starch formation in cassava starch through v-amylose complexation with fatty acids and phenolic compounds

Amylose forms V-type inclusion complexes with guest molecules, resulting in resistant starch type 5 (RS5), but the structural and functional properties of these complexes, which simultaneously incorporate lipids and polyphenols in cassava starch are not well understood. This study examined the effects of stearic acid, lauric acid, gallic acid, and quercetin, used individually and in combination, on V-amylose complex formation, crystalline structure, physicochemical properties, and starch fractions of cassava starch. The starch was modified via heat-moisture treatment with 10 % of each compound. The co -application of fatty acids and polyphenols significantly elevated the complexing index from 1.98 % (native starch) to 50.09 % in cassava starch with lauric acid and quercetin, and 47.75 % with stearic acid and quercetin. X-ray diffraction results showed a crystalline transition from A-type to a mixture of A- and V-type patterns, confirming the formation of V-amylose inclusion complexes. Differential scanning calorimetry showed elevated gelatinization temperatures and enthalpy values, suggesting enhanced thermal stability. Fourier-transform infrared spectroscopy detected shifts in absorption bands, supporting the formation of a stabilized tertiary structure. These transformations decreased rapidly digestible starch (RDS) and increased the slow digestible starch (SDS) and RS fractions. The combination of stearic acid and quercetin exhibited the most prominent synergistic impact, producing the lowest RDS (64.13 %) and the highest RS levels (6.88 %). These results highlight the potential of amylose–lipid–phenolic complexation as an effective strategy to enhance RS5 formation and improve the functional quality of cassava starch.