Sensory-Driven Optimization of Carob (Ceratonia siliqua L.)-Enriched Jelly Candies Using Response Surface Methodology and Sensory Profiling

Abstract

A multivariate sensory analytical methodology integrating response surface methodology, descriptive sensory analysis and principal component analysis was developed and validated for optimizing carob-enriched jelly candy formulations. Preliminary experiments compared three carob incorporation strategies in a pectin-based gel matrix, demonstrating that coating with carob flour provided the most suitable technological approach, whereas direct flour incorporation and syrup concentrations above 1% adversely affected product texture. Based on these findings, a central composite design was applied to optimize carob syrup (0.5–1.5%) and coating carob flour (30–70%) levels. Response surface methodology identified odor and texture as the hedonic sensory responses most significantly affected by formulation, with maximum overall acceptability predicted at 0.52% carob syrup and 31.4% coating carob flour. Descriptive sensory analysis revealed brown color intensity and hardness as the principal discriminating attributes among formulations, while carob odor and flavor differentiated only a subset of samples with high panel reproducibility. Principal component analysis further confirmed distinct sensory profiles associated with the combined effects of coating and syrup concentrations. The optimized formulation (desirability = 0.63) exhibited a balanced sensory profile characterized by moderate brown color, good elasticity, and low carob aroma intensity, while maintaining physicochemical and sensory stability during 15 days of storage, with moisture loss below 2% and no perceptible quality deterioration. The study revealed meaningful relationships between formulation parameters and the sensory and hedonic characteristics of carob-based gummy candies, demonstrating the value of a sensory-driven approach to formulation assessment.