Kinetics of Phenolic Compounds Modification during Maize Flour Fermentation

Abstract

This study aimed to investigate the kinetics of phenolic compound modification during the fermentation of maize flour at different times. Maize was spontaneously fermented into sourdough at varying times (24, 48, 72, 96, and 120 h) and, at each point, the pH, titratable acidity (TTA), total soluble solids (TSS), phenolic compounds (flavonoids such as apigenin, kaempferol, luteolin, quercetin, and taxifolin) and phenolic acids (caffeic, gallic, ferulic, p-coumaric, sinapic, and vanillic acids) were investigated. Three kinetic models (zero-, first-, and second-order equations) were used to determine the kinetics of phenolic modification during the fermentation. Results obtained showed that fermentation significantly reduced pH, with a corresponding increase in TTA and TSS. All the investigated flavonoids were significantly reduced after fermentation, while phenolic acids gradually increased during fermentation. Among the kinetic models adopted, first-order (R2 = 0.45–0.96) and zero-order (R2 = 0.20–0.82) equations best described the time-dependent modifications of free and bound flavonoids, respectively. On the other hand, first-order (R2 = 0.46–0.69) and second-order (R2 = 0.005–0.28) equations were best suited to explain the degradation of bound and free phenolic acids, respectively. This study shows that the modification of phenolic compounds during fermentation is compound-specific and that their rates of change may be largely dependent on their forms of existence in the fermented products.

Reduction in the Cocoa Spontaneous and Starter Culture Fermentation Time Based on the Antioxidant Profile Characterization

“…In addition, the pH tended to decrease at the end of the fermentation process (in SF, it reached 4.48, and in SC, it reached 4.34; see Table S2). The results are similar to those obtained by De Vuyst and Weckx [47], where the decrease was in the range of 4.5-5 (well-fermented beans), and in the study of Calvo et al [39], who recorded pH values from 4.5 to 4.8, which can be explained by the activity of the fermenting bacteria (lactic and acetobacter) that promote the incorporation of organic acids [36,[48][49][50]. Following the behavior of internal pH, Afoakwa et al [51] and Dewandari et al [49] consider that a pH close to 5.0 is related to cocoa with better aromatic and sensory profiles; in our study, a pH of 4.9 and 5.5 (Figure 3) was observed in SF between 48 and 96 h, while in SC, it was between 48 and 72 h, indicating a difference in the final cocoa quality [39]; the data are presented in the Supplementary Material (Table S2).…”

Effects of Five Different Lactic Acid Bacteria on Bioactive Components and Volatile Compounds of Oat

“…According to previous reports, flavonoids can be transformed into free forms in the fermentation process of soybean and tea, but a decrease in the total amount may not indicate a decrease in biological activity. Bound and free flavonoids decreased during the fermentation of corn and other grains [ 37 ]. Researchers attributed this to the metabolism of these compounds during microbial fermentation, such as the degradation/polymerization of flavonoids into dihydroxy flavonoids analogues and the activity changes of enzymes, including glycosidase, glycosyltransferase, tannase, esterase, and hydrolase [ 34 ].…”

Integrated Microbiomic and Metabolomic Dynamics of Fermented Corn and Soybean By-Product Mixed Substrate

“…Therefore, many processing technologies like physical and chemical methods have been applied to corn and soybean-based foods to enhance the nutritional value of the final products. However, these processing tools are un-environmental friendly and lose nutrients ( 6 ).…”