Influence of nixtamalization time and solid-state fermentation on masa starch: Morphology, structure, and physicochemical properties

Abstract

In this paper, the effect of two cooking times of nixtamalization (30 and 90 min) and solid-state fermentation masa was investigated. The morphological analysis of the starch grains showed that longer nixtamalization times (90 min) lead to greater damage. The reducing sugars content increased 5.9 times at 90 min compared to 30 min nixtamalization during solid-state fermentation (SSF). The pH value at the end of SSF was below 4.5 for both nixtamalization times. In terms of the thermal properties, it was observed that at 90 min of nixtamalization, the starch granules presented greater gelatinization degree (50.94 %). Furthermore, in the SSF decreased maximum viscosity 4.8 times at 90 min than 30 min. The X-ray diffraction pattern showed nanocrystals with orthorhombic crystal structure in starch, relative crystallinity decreased at 0.9354 and 0.876 in the 30 and 90 min of nixtamalization respectively with SSF. Finally, infrared spectrum, changes were observed in the starch groups of the masa. In conclusion, the nixtamalization time changed the morphology, the production of reducing sugars and lactic acid, thermal properties, and viscosity during SSF, possibly due to the changes that the starch undergoes, making it more susceptible to the enzymatic activity of the microorganisms as lactic acid bacteria mainly.