Rheological, bioactive and sensory properties of dark chocolates elaborated with stevia sweetener and freeze-dried berries

• Stevia sweetener increased viscosity, yield strength and hardness of chocolates. • Increased thermal stability was observed in chocolates with the incorporation of dehydrated blueberry and blackberry powders. • The physicochemical and sensory properties of the dark chocolates were influenced by the type of berries incorporated (goldenberry, blueberry and blackberry). The chocolate industry is progressively seeking to incorporate novel ingredients in order to satisfy the demand for innovative products. Nevertheless, the modification of formulations in chocolates can result in alterations to their properties. This study aimed to evaluate the rheological, bioactive and sensory properties of dark chocolates by adding freeze-dried berries and stevia sweetener. The chocolate tablets were formulated with four dried berry pulps and three doses of stevia sweetener. It was found that the addition of stevia at any of the concentrations tested increased the viscosity (2.97 ± 3.84 Pa-s), yield strength (11.6–17.6 Pa), and hardness (42.06 ± 3.10 N) of the chocolates, benefiting the texture and heat resistance of dark chocolates. Moreover, the incorporation of stevia resulted in enhanced thermal stability and antioxidant capacity, indicating a probable enhancement in product quality. The chocolates containing blackberry and a stevia sweetener concentration of 0.2 % received the highest ratings for color (7.46 ± 0.20), while those containing blueberry and a stevia sweetener concentration of 0.4 % received the highest ratings for texture and flavour (7.66 ± 0.90). In conclusion, this work demonstrated that the incorporation of stevia sweetener and dehydrated berry pulp can improve the physicochemical and sensory characteristics of dark chocolates, improving their thermal stability and sensory acceptability.