Physicochemical properties and antioxidant capacity of purple Mashua yogurt

Abstract

Objective: To determine the physicochemical characteristics and antioxidant potential of yogurt optimized with Tropaeolum tuberosum (“purple mashua”). Methodology: Natural yogurt was prepared and mashua puree was added in five different concentrations (16.67, 33.45, 50.04, 66.33 and 83.55 g per liter of yogurt); the optimum concentration was determined using the cut-off point graphical method. The physicochemical properties (pH, titratable acidity, density, syneresis and viscosity), the antioxidant potential by ABTS+ assay, the amount of total polyphenols by Folin-Ciocalteu colorimetric reaction were evaluated. Results: The concentration of optimized pure de mashua purpura added to plain yogurt was 55.67 g. Its physicochemical properties were as follows. Its physicochemical properties were: pH: 4.40, titratable acidity 0.61 % lactic acid, density 1.051 g/cc, syneresis 39.62 and viscosity 998.63 cp. It presents an antioxidant activity of 420.56 uMol ET and total polyphenols of 951.36 mg Gallic Acid Equiv. per 100 grams of yogurt. Conclusions: With the inclusion of 55.67 g of purple mashua puree and 19.62 g of stevia per liter of plain yogurt, an acceptable product is produced with a similar color to commercial blackberry yogurt. In addition, the product improves its physicochemical properties and antioxidant capacity.