Chemical and sensorial characterization of Tejate, a Mexican traditional maize-cocoa beverage, and improvement of its nutritional value by protein addition

Tejate is a Mexican traditional beverage elaborated with nixtamalized maize (Zea mays L.), cocoa (Theobroma cacao L.) beans, cacao flowers (Quararibea funebris), and mamey sapota fruit seeds (Pouteria sapota) that is considered a refreshing drink with satiety properties. Local formulations show a high content of minerals, but a relatively low protein content. The aim of this study was to identify a standardarized formulation but conserving physicochemical and sensorial ethnic identity of traditional Tejate, and to improve its nutritional value with the addition of protein without modifying its sensorial profile. A 2^4–1 fractional factorial design with central point was used to vary ingredients concentration and the amount of ash used for maize nixtamalization instead of lime (calcium hydroxide) was 75 g/100 g (w/w) of wood ashes in 2 L water. The standardized traditional formulation (TF) was selected through a sensory analysis with an expert panel: 20 g of cacao flowers, 30 g of mamey sapota fruit seeds, and 100 g of cocoa beans per kg of maize nixtamalized with 6% of ash. Whey protein concentrate (80% of protein) or soy protein isolate (88% of protein) were added to the TF at 1, 2, and 2.5%. The addition of 1% soy protein isolate increased TF protein content without modifying its physicochemical parameters, and improved the beverage stability during cold storage. The protein-rich Tejate formulation could be used as a functional beverage maintaining its ethnic identity.