Physicochemical and functional modifications induced by purple corn flour (Zea mays L.) and their sensory...

The incorporation of functional ingredients, such as purple corn flour, into bakery products has attracted considerable attention due to its high content of bioactive compounds with potential health benefits. However, technological limitations and possible impacts on sensory acceptance still represent significant challenges. This study aimed to evaluate the effects of purple corn flour incorporation on the physicochemical, functional, and sensory properties of loaf bread, as well as to examine the relationship between compositional changes and consumer acceptance.

Five bread formulations were developed: one control formulation (100% wheat flour) and four formulations with partial replacement of wheat flour at levels of 15 and 30% using purple or yellow corn flour. The analyses included proximate composition, total phenolic content, antioxidant activity, and instrumental texture profile. Phenolic compounds were identified by high-performance liquid chromatography (HPLC). Sensory acceptance was evaluated by 100 consumers using a 9-point hedonic scale. Partial least squares regression (PLS-R) was applied to correlate compositional parameters with sensory responses.

The incorporation of purple corn flour, particularly at the 30% substitution level, significantly increased protein content (15.59 ± 1.33 g/100 g), dietary fiber (2.04 ± 0.05 g/100 g), total phenolic compounds (ranging from 58.22 ± 1.11 to 243.22 ± 9.57 μg GAE g^-1), and antioxidant activity. HPLC analysis identified gallic and chlorogenic acids, with catechin as the predominant phenolic compound. Higher substitution levels resulted in increased hardness and adhesiveness. Sensory evaluation indicated that breads containing 15% substitution showed acceptance comparable to the control, whereas 30% substitution significantly reduced consumer preference. Multivariate analysis demonstrated that acceptance was positively associated with carbohydrate and energy content, while fiber, lipid, and moisture contents were negatively correlated with perceived quality.

Moderate incorporation of purple corn flour represents a viable strategy to improve the nutritional and functional profile of bread while maintaining acceptable sensory quality. These findings reinforce the importance of balancing formulation strategies with consumer perception and support the application of purple corn flour in the development of functional bakery products.