Evaluation of the Effects of Fermentation with Natural Sourdough on the Phytic Acid Content of Corn Flour Produced in Guinea

Abstract

In Guinea, iron and zinc deficiencies represent a major public health problem, exacerbated by the consumption of cereal-based foods rich in phytic acid, which reduces the bioavailability of these minerals. Natural fermentation of flours offers a simple approach to improving this availability. This study aimed to evaluate the effects of corn flour fermentation with a natural starter on phytic acid levels and fermentation parameters. The resulting flour was mixed with distilled water (1 : 1, 1 : 2, and 1 : 3 (w/v)). These suspensions were used to perform three fermentation conditions: fermentation with starter consisting of sterilized corn flour suspension and natural sourdough (2, 5, and 10%) (FFL); spontaneously fermented flour (FFS), composed of an unsterilized corn flour suspension without a starter; and a control composed solely of sterilized corn flour suspension without the addition of sourdough (FT). The results obtained show that after 48 h of fermentation, the pH varied from 5.71 ± 0.0071 to 3.41 ± 0.057, and the acidity evolved from 4.68 ± 0.062 to 13.63 ± 0.035 g/L in the samples (FFL, 1 : 3, 10%). A similar trend was observed in the samples (FFS, 1 : 3), where the pH went from 5.96 ± 0.0035 to 3.53 ± 0.0245 and the acidity from 2.04 ± 0.057 g/L to 11.37 ± 0.014 g/L. In FFS and FFL, a significant variation (p < 0.05) in phytic acid contents was observed; it went from 0.369 g/100 g in raw flour to 0.249 ± 0.057, 0.230 ± 0.071, and 0.196 ± 0.106 g/100 g in FFS samples with flour/water ratios of 1 : 1, 1 : 2, and 1 : 3 after 48 h of fermentation, respectively. FFL samples showed a variation, reaching 0.102 ± 0.028 g/100 g in the sample (FFL, 1 : 3, 10%). The present study shows that natural fermentation is significantly more effective than spontaneous fermentation in reducing phytic acid.