Microstructural Changes and In Vitro Digestibility of Maize Starch Treated with Different Calcium Compounds Used in Nixtamalization Processes

Abstract

Maize starch dispersions (5 g/100 mL water) are treated with Ca(OH)2 (0.2 g/100 g starch), emulating the traditional nixtamalization process, and with CaCl2 or Ca(CO)3 (1.0g/100 g starch) salts, emulating ecological nixtamalization processes. The effect of these calcium compounds upon the in vitro digestibility of maize starch is evaluated in comparison to an untreated starch dispersion used as control. The Ca(OH)2 treatment significantly increases the rapidly digestible starch (RDS) fraction (from ≈33 to 64%) and significantly decreases the slowly digestible starch (SDS) fraction (from ≈63 to 30%), while both salt treatments lead to significant decreases in the RDS fraction (from ≈33 to 17%) and significant increases in the SDS fraction (from ≈63 to 76%), and resistant starch (RS) fraction (from ≈2.8 to 6.8%), compared to the untreated control. The mechanisms responsible for causing changes in the digestible starch fractions are not fully elucidated. Optical micrographs and different analytical methods (rheology, attenuated total reflection Fourier transform infrared, X‐ray photoelectron spectrometry and nuclear magnetic resonance) are used to explore the molecular organization of untreated and the different calcium‐treated samples. It is found that the disruption of insoluble remnants (ghosts) by alkali treatment and the formation of calcium‐mediated cross‐linking structures play an important role in the in vitro digestibility and microstructural changes of maize starch.

Characterization of Corn Starch‐Calcium Alginate Xerogels by Microscopy, Thermal, XRD, and FTIR Analyses

“…[ 33,34 ] The shifting to distant positions may be reflecting the formation of calcium‐mediated ordered structures. [ 35 ] Table 3 also presents the intensity ratios R h / a and R o / a for the xerogel variations. The magnitude of both ratios increased with the starch content.…”

Calcium Biofortification of Crops–Challenges and Projected Benefits

“…Calcium carbonate and Ca chloride have also been used as nixtamalization agents, and experiments conducted on maize plants showed that treatment with these agents could lead to modifications in the digestibility of resistant and soluble starches (Roldan-Cruz et al, 2020). Cooking reduces the oxalate content of the food by discharging losses into the cooking water (Savage et al, 2000).…”

El maíz y la nixtamalización: modificación de sus componentes, técnicas de proceso y enriquecimiento de tortilla.

“…(2020) 60 asegura que brinda mayor viscosidad debido a que, de acuerdo a estudios de digestión in vitro, contiene mayor almidón de lenta digestión, así como más almidón resistente, en comparación con el tratamiento tradicional, lo cual beneficia la cantidad de fibra de la tortilla.…”