Abstract

SALINAS-MORENO, Yolanda; LOPEZ-REYNOSO, José de J.; GONZALEZ-FLORES, Guadalupe B.  and  VAZQUEZ-CARRILLO, Gricelda. Phenolic compounds of maize grain and their relationship with darkening in dough and tortilla. Agrociencia [online]. 2007, vol.41, n.3, pp.295-305. ISSN 2521-9766.

Some maize varieties and hybrids cultivated in the State of México become dark when made into dough and tortillas. The cause of this darkening is not known, but phenolic compounds in the grain could be involved. The objectives of this study were to determine whether the content of phenolic compounds in maize grain is related to darkening of dough and tortillas made from the evaluated maize varieties, and to obtain the profile of phenolic acids in samples of maize whose dough and tortillas exhibit this phenomenon. Ten samples of maize selected for the color of their tortillas were used: five were classified as samples that darken (MQO) and five were classified as samples that do not darken (MQNO). The content of free (FL) and total (FT) phenols was quantified in the endosperm and pericarp of the raw grain, as well as in dough and in tortillas following the method of Folin-Cicalteu; the phenolic acid profiles was obtained with high precision liquid chromatography (HPLC). The highest concentration of FL and FT was found in the grain pericarp, with no significant differences between the MQO and MQNO. In the endosperm a higher concentration of these compounds was found in the MQO than in the MQNO. This same trend was observed for dough and tortilla, where FT content of the latter was 39% higher in MQO than in MQNO. In the raw-grain pericarp and endosperm of both groups of samples p-cumaric, ferulic, and sinapic acids were observed; the proportion of ferulic acid was higher. These same acids were found in the free phenol extract from dough of both groups of samples.

Keywords : Phenolic acids; maize; nixtamalization; darkening; tortilla.

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