Development of Value-Added Chocolate with Oat and Evaluation of Its Physiological Properties

Abstract

This study was performed to investigate the physicochemical properties of oat chocolate. Oat samples were roasted at various temperatures (0, 80, 120, 160 and 200 °C) for 15 min. Oat chocolates were made by using three natural antioxidants (green tea, lavender and cactus). The acid value, Hunter's color, pH, total acidity and sensory evaluation of oat chocolates were determined. Results showed that the acid value of roasted oat flour significantly decreased with increasing roasting temperature. Its sensorial characteristics, such as color, taste, smell and overall preference were increased relative to a temperature rise. As for oat chocolate mixture, its acid value significantly decreased as more antioxidants were added (p < 0.05). The lowest acid value was recorded with chocolate lavender flour after 7 d at 1%. Findings showed that the sensory characteristics of products containing antioxidants, such as green tea and cactus, were superior to the control treatment within 7 d. A product including 0.5% green tea marked the best sensory score among antioxidants. Compared cost among three antioxidants, green tea was the cheapest. In the end, 0.5% green tea was selected as the optimal antioxidant to make high-quality oat chocolate. An end product by mixing green tea (0.5%) and oat was made. With respect to Hunter's color L (whiteness), a (redness) and b (yellowness), L and a levels were higher when green tea was added. However, an opposite result was expressed in b level. In terms of pH value and total acidity, the control (without antioxidant) and product with 0.5% green tea (G-0.5) were statistically identical with each other. There was difference in acid value among specimens. The acid value of G-0.5 was lower than that of the control up to 7 d, resulting in lower acid value than the ready-made product (D-Co.). When sensory characteristics were assessed, G-0.5 scores were higher than other specimens, including the control and ready-made products (D-Co. and H-Co.) up to 6 d after the manufacturing date. As a result, the addition of 0.5% green tea increased the antioxidative effect, as well as the sensory acceptability of oat chocolate.