Optimization of Fortified Milk Chocolate Formulation with Chia Seed Oil, Vitamin D3, and Calcium by Surface Response Method

In the present research, the optimization of formulation of fortified chocolate using Chia seed Oil as source of Omega-3, vitamin D3 and calcium was investigated by surface response method.Different amounts of calcium (60, 95 and 130 mg), vitamin D3 (0.5, 0.75 and 1 μg) and Chia Oil (1, 3 and 5 mg) were added to the chocolate in the 20 formulations designed by Design Expert software and the sensory properties of the fortified chocolates were then tested by the evaluators. Based on the analysis of response surface method, 24 optimized samples were proposed by the software, all of which contained Omega-3 in the minimum range (1 mg) and calcium in the maximum range (130 mg) and three formulas were selected that they differed only in the amounts of vitamin D3 (0.5, 0.75 and 1 μg). Texture and thermal analysis, colorimetery, moisture, water activity and peroxide value tests were performed on these samples at first and 3 months later. Evaluation of sensory properties showed that the taste, texture and overall acceptance parameters of fortified chocolates were reduced compared to control (p <0.05). The whiteness index and water activity compared to the control were increased and decreased, respectively. However, the hardness and the peroxide values of the treatments were not changed significantly with respect to the control. The start temperature of melting of the fortified chocolate decreased compared to the control, while their melting points were the same. Due to taste and flavor of Omega-3, the overall acceptability of the fortified chocolates seems to decrease.