# Shedding Light on the Volatile Composition of _Broa_, a Traditional Portuguese Maize Bread
## 3 Results and Discussion
### Characterization of the Volatile Composition of Broas
#### 3.4.3 _Broas_' Sensory Analysis and Volatile Composition  
The results obtained from a consumer sensory evaluation of _broas_[43] were retrieved and compared here with their volatile composition, in order to determine the volatile compounds that might contribute to _broas_ sensory characteristics. The sensory analysis scores are presented in Supplementary Table S9 and the correlations among these scores and _broas_' volatile compounds are presented in Supplementary Table S10. As previously reported [43], the sensory analysis revealed poor discrimination among the 11 samples prepared from traditional maize varieties. The _broa_ prepared from the commercial maize flour (B12) showed the lowest mean scores for all the evaluated attributes ('appearance','smell and odor', 'texture', 'taste and aroma', 'color' and 'global appreciation'). In addition, the majority of the negative comments were attributed to this sample, including 'dry texture', 'weak typical flavor', 'wheat bread flavor', 'with a weak maize flavor' and 'no history'. As previously discussed, the commercial _broa_ was distinguished from all the traditional _broas_ (Figure 5 and Table 4), essentially due to its higher contents in volatiles derived from lipid oxidation reactions, such as 2-octenal, which was very strongly and negatively correlated (R = -0.746, \(p\) < 0.01) with 'taste and aroma' scores. This aldehyde contributes to fatty, nutty, waxy and green notes [20; 51]. This sample was also characterized by higher contents in benzyl alcohol, an extremely aroma-active compound associated with pleasant notes [15; 17; 20]. However, benzyl alcohol has been described in rye breads as a major factor responsible for their intense and bread-like flavors [16], and thus can contribute to a more bread-like flavor in _broas_. Hence, it may contribute to aroma characteristics in _broas_ that are not typical of this type of bread, giving rise to some of the negative comments described above. It can also be responsible for a bitter taste [79], which was also referred to as a negative characteristic of this particular _broa_. The _broa_ B8 scored higher for the majority of the sensorial attributes ('color','smell and odor', 'texture' and 'global appreciation') and was often described by the consumer panel as 'the tastiest' and 'with a good maize flavor'. This sample belonged to cluster 1, together with B6 and B7, characterized by higher contents in compounds resulting from the baking process associated with positive notes [19; 20; 21; 24], particularly maltol, 1-furfurylpyrrole and 2-acetylpyrrole. Interestingly, these compounds have not been reported as abundant in other breads [20], but have been described in popcorn [24; 36], extruded maize products [14] and tortilla chips [80], suggesting that they can have a contribution to the characteristic-maize-based foods, and particularly _broas_' sweet aroma. Significant positive correlations were found between 'taste and aroma' scores and pyranones content (maltol and 3-hydroxy-2,3-dihydromaldol). Despite the relatively high odor threshold of 9 mg/kg (water), maltol was very abundant in the B8 sample, which showed the highest maltol content of all _broas_ (Supplementary Table S5). It has a caramel-like odor and enhances the sweet taste of food [21]. In contrast, B12 showed the lowest contents of maltol of all _broas_, which also supports its importance on _broas_ 'taste and aroma'. B1 showed the second lowest contents in maltol and had the lowest contents in 3-hydroxy-2,3-dihydromaldol of all _broas_. Some of the comments attributed to B12, such as 'weak typical flavor' and 'weak aroma and flavor' were also attributed to B1, which was the sample with the lowest 'taste and aroma' scores among all _broas_ prepared from traditional maize flours. As previously discussed, F1 was differentiated from all the other traditional maize flours (Table 3 and Figure 3) due to its higher contents in volatiles from lipid oxidation, in particular 2-octenal (_E_).