The effect of different nixtamalisation processes on some physicochemical properties, nutritional composition and glycemic index

The objective was to evaluate corn tortillas made from three nixtamalisation processes including Traditional with lime (TNP), Classic with ashes (CNP) and Ecological with Ca salts (ENP), and their effect on mineral content (Ca, Fe, K, and Mg), chemical composition, resistant starch (RS), and glycemic index (GI). ENP with calcium propionate and carbonate had higher fat values than tortillas from CNP. EPN and CNP presented the higher dietary fibre, explained by the highest pericarp retention. In TNP the pericarp and external layers were lost during the cooking, steeping and washing steps and had lower crude fiber. The amount of RS increased in nixtamal and tortillas independently of nixtmalisation processes. Annealing of starch was shown by the increase of onset, peak and final gelatinisation temperatures in nixtamalised products compared with untreated maize. Gelatinisation was higher for calcium propionate ENP and 1% ash CNP. Native maize changed from A-type to V-type pattern in nixtamalised products denoting the formation of amylose-lipid complexes. Overall, nixtamalisation processes and salts used increased RS. The GI was affected by chemical composition in tortillas and amount of RS. Tortillas made from ENP Ca propionate and ENP 1% ash CNP can be classified as low GI foods.