Physicochemical properties and sensory acceptability of sugar free chocolate formulations added with fish oil and probiotics

Metabolic syndrome is a worldwide multifactorial disorder associated with central obesity through a high caloric intake and a sedentary lifestyle. Metabolic syndrome increases the risk of type 2 diabetes (T2D) disease. A strategy proposed by the food industry to reduce this problem is the generation of low-caloric products using sweeteners, which are compounds that can substitute sucrose because of its sweet taste. Likewise, nutraceuticals can prevent diseases related to metabolic syndrome. Thus there is an interest in the market for the development of functional foods added with nutraceuticals such as omega-3 (w-3), polyunsaturated fatty acids (PUFAs) from fish oil (FO), and probiotics (Prob). Chocolate has been considered an adequate vehicle to deliver w-3 PUFAs and Prob due to its ingredients' protective properties. However, little information is reported on developing sugar-free chocolate formulations added with Prob and FO. Therefore, the present thesis evaluated the physicochemical properties and the sensory acceptability of sugar-free chocolate formulations added with FO and Prob. In the first phase, the effect of microencapsulated Prob strains [Lactobacillus plantarum 299V (L299V) and Lactobacillus acidophilus La 3 (DSMZ 17742)] on the physicochemical properties (texture, instrumental color, and water activity) and consumer' acceptability of two different sugar-free dark chocolate formulations was evaluated. The combinations of sweeteners used were polydextrose + inulin (Pol+Inu) and isomalt + stevia (Iso+Stev). The viability of Prob resulted in 1.2X109 CFU per serving size (12 g) of dark chocolate. Likewise, Prob addition alone (without sugar replacement) did not affect the physicochemical properties and sensory acceptability of dark chocolate; however, sweeteners addition significantly affected the product's physicochemical and sensory acceptability chocolates added with Iso+Stev showed the nearest characteristics as compared with the control. In the second phase, the effect of sugar replacement, as well as Prob and FO addition on the physicochemical effect (texture, instrumental color, rheology, and water activity) and consumer' acceptability of different milk chocolate formulations was evaluated. A mixture of Iso+Stev as sugar replacer was used. Chocolates added with Prob contained 2x107 CFU per serving size. Prob addition increased the whiteness index (WI), decreased hardness, and modified the rheological properties, increasing the shear stress of chocolates. Furthermore, FO addition did not affect the WI values, decreased hardness, and generated a liquid-like rheological behavior. FO, Iso+Stev+FO, and Iso+Stev+Prob+FO contained 107.4±12.8 mg, 142.9±17.9 mg, and 133.78±8.76 mg of ω-3 PUFAs per chocolate portion, respectively. The substitution of sucrose using Iso+Stev decreases WI values, and the combination Iso+Stev and Iso+Stev+Prob showed the nearest hardness values compared with the control. Also, sugar substitution and ω-3 PUFAs addition (Iso+Stev+FO) showed a similar flow behavior as compared with the control. Finally, sugar-free chocolates added with Prob and FO (Iso+Stev+FO+Prob) showed higher acceptability as compared with FO+Prob. Based on these results, the Iso+Stev+Prob milk chocolate formulation showed a promising sugar-free product with adequate acceptability by consumers. Likewise, Iso+Stev increased the stability of ω-3 PUFAs (Iso+Stev+FO and Iso+Stev+Prob+FO) during processing compared with chocolates containing sucrose and FO. However, other sources of FO should be tested in chocolate formulations to improve their sensory acceptability. More rheological and textural analyses are needed to understand better the particle-particle interaction of the new ingredients added in the chocolate matrix and improve chocolates' texture. Likewise, the formulations presented herein should be further investigated to determine their potential impact on the prevention and treatment of type 2 diabetes.

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