Chain Length and Degree of Saturation of Cooking Fats Influence the Inherent Glycemic Potential of Dietary Starches

Lipid-induced digestive resistance could be an affordable management strategy to lower the glycemic amplitude of dietary starch. This study evaluated the influence of fatty acid (FA) composition, chain length, and saturation of five cooking fats—ghee (GH), coconut oil (CO), sunflower oil (SO), mustard oil (MO), and til oil (TO)—on the inherent glycemic potential (IGP) of starches from pearl millet (PM) and rice. Starch–lipid (S-L) complexes were analyzed using in vitro starch hydrolysis kinetics. The inclusion of cooking fats in starches resulted in higher resistant starch (RS) content, which was attributed to the formation of stable S-L structures. Fourier transform infrared spectroscopy and x-ray diffraction revealed that GH and MO-induced complexes exhibited longer and shorter starch molecule assemblies in PM and rice, which ultimately limited the IGP to 57.13% and 58.87%, respectively. Subsequently, the in vitro glucose diffusion assay validated the lesser glucose bioavailability from MO-induced starch complexes in the system, revealing the correlation among chain length and degree of saturation of cooking fats in the context of IGP of dietary starches. Henceforth, by understanding these S-L interactions, newer food prototypes could be designed in the near future.