Broa, an Ethnic Maize Bread, as a Source of Phenolic Compounds

Abstract

Maize is an important source of phenolic compounds, specially hydroxycinnamic acids, which are widely known for their antioxidant activity and associated health benefits. However, these effects depend on their bioaccessibility, which is influenced by the different techniques used for food processing. Several traditional products can be obtained from maize and, in Portugal, it is used for the production of an ethnic bread called broa. In order to evaluate the effect of processing on maize phenolic composition, one commercial hybrid and five open-pollinated maize flours and broas were studied. The total phenolic content and antioxidant activity were evaluated by the Folin-Ciocalteu and ORAC assays, respectively. The major phenolics, namely ferulic and p-coumaric acids (in their soluble-free, soluble-conjugated and insoluble forms), insoluble ferulic acid dimers and soluble hydroxycinnamic acid amides were quantitated. Results show that the total phenolic content, antioxidant activity and hydroxycinnamic acids resisted traditional processing conditions used in the production of broas. The content in soluble-free phenolics increased after processing, meaning that their bioaccessibility improved. Portuguese traditional broas, produced with open-pollinated maize varieties, can be considered an interesting dietary source of antioxidant compounds due to the higher content in hydroxycinnamic acids and derivatives.

Shedding Light on the Volatile Composition of Broa, a Traditional Portuguese Maize Bread

“…Thus, these results suggest that phenolic compounds may: (1) act as antioxidants, inhibiting lipid oxidation reactions in both maize flours (Figure 2) and broas (Figure 4), (2) inhibit amylases and yeast fermentation (Supplementary Figure S4) and (3) act as pro-oxidants during baking, increasing the levels of Maillard and caramelization volatiles (Supplementary Figure S5). As previously reported [41], some insoluble phenolic compounds may become soluble after maize processing to broas, increasing their content in soluble phenolic compounds. Therefore, the increasing levels of phenolic compounds during bread making may have contributed to their action as pro-oxidants, thus increasing the level of Maillard derivatives.…”

“…Phenolic compounds of maize flours and broas were extracted with 50% aqueous ethanol, and the major soluble phenolic compounds (ferulic acid, p-coumaric acid, diferuloyl putrescine, p-coumaroyl feruloyl putrescine, dicoumaroyl spermidine and bis-diferuloyl putrescine) were quantitated by HPLC-DAD (high-performance liquid chromatography coupled to a diode array detector), following the procedures previously described [38,41].…”

Arabinoxylan from Corn Fiber Obtained through Alkaline Extraction and Membrane Purification: Relating Bioactivities with the Phenolic Compounds

“…The antioxidant activity is most likely due to the presence diverse of hydroxycinnamic acids, such as ferulic and p-coumaric acid in solution; they are both known antioxidants and their antioxidant activity in terms of ORAC has been previously reported as 15.6 ± 1.10 and 23.0 ± 2.7 µmol TEAC/mg for ferulic and p-coumaric acid, respectively [7]. Other hydroxycinnamic acid derivates compounds like dicoumaroyl spermidine, an amide derivate, as well as dehydrodiferulic acid, a ferulic acid dimer, both still present in the purified extract with pre-separation (see Table S1), have been reported to contribute to the antioxidant activity of maize flours [16].This means that the lower the concentration of these acids in the solution, the lower the antioxidant activity. As expected, the purified extracts that had a lower concentration of ferulic and p-coumaric acid (they were also less rich in phenolic compounds) also presented the lowest antioxidant activity.…”

Improvement of wheat cookies’ nutritional quality, by partial substitution with common bean and maize flours, sustained human glycemia and enhanced satiety perception

“…The presence of common bean flour also improved the cookies’ final phenolic content and antioxidant activity, Table 3. Although maize flour, also contributed to total phenolic content of the final formulated cookie, 1.50–2.76 mg/g dry weight, (Bento‐Silva et al., 2021), the higher proportion of raw common bean flour compared to the maize flour (2.5:1) and the high level of phenolic compounds in the Moleiro common bean variety, 3.36 mg GAE/g dry weight (Mecha et al., 2020), anticipated an higher contribution of common bean flour to the final phenolic composition of common bean enriched cookies.…”