Comparative study of instrumental properties and sensory profiling of low-calorie chocolate containing hydrophobically modified inulin. Part 1: Rheological, thermal, structural and external preference mapping

Low-calorie chocolate was prepared using replacement of sucrose by hydrophobically modified inulin (dodecenyl succinylated inulin) as biopolymeric surfactant at different levels (100:0, 75:25, 50:50, 25:75, and 0:100%). The instrumental parameters of produced chocolates before and after storage were compared with their sensory evaluation. Morphological assay showed that the lowest modified inulin ratio allowed an increase in frequency of surface crystals upon storage with progress of blooming phenomenon. However, higher levels of modified inulin were more effective in enduring blooming. Replacement of lowest inulin ratio increased elastic modulus of stored chocolate, with a more solid-like behavior. However, viscoelastic parameters of stored chocolates with higher modified inulin contents remained similar to the levels obtained for non-stored samples. Thermal analysis revealed that enthalpy increased in stored chocolate containing lowest modified inulin content due to post crystallization, while substitution of modified inulin at higher levels seemed to slow down this process. Upon storage, V-type crystal was transformed to VI-type form in chocolate formulated with the lowest modified inulin proportion, while chocolates with higher inulin contents showed the slowest change in polymorphic transformation. Quantitative descriptive analysis revealed that increasing inulin content resulted in good textural and color appearance. Partial least squares showed that blooming, mass forming, cracking and powderiness attributes were responsible for lower consumer acceptance of chocolate.