Temporal Texture Profile and Identification of Glass Transition Temperature as an Instrumental Predictor of Stickiness in a Caramel System

Stickiness is an important texture attribute in many food systems, but its meaning can vary by person, product, and throughout mastication. This variability and complexity makes it difficult to devise analytical tests that accurately and consistently predict sensory stickiness. Glass transition temperature (T-g) is a promising candidate for texture prediction. Our objective is to elucidate the temporal profile of stickiness in order to probe the relationship between T-g and dynamic stickiness perception. Nine caramel samples with diverse texture and thermal profiles were produced for sensory testing and differential scanning calorimetry. Sixteen trained panelists generated stickiness-relevant terms to be used in a subsequent temporal dominance of sensation (TDS) test with the same panelists. Following the TDS study, these panelists also rated samples for overall tactile and oral stickiness. Stickiness ratings were then correlated to TDS dominance parameters across the full evaluation period and within the first, middle, and final thirds of the evaluation period. Samples with temporal texture profiles dominated by tacky, stringy, and enveloping attributes consistently received the highest stickiness scores, although the correlation strength varied by time period. T-g was found to correlate well with trained panelist and consumer ratings of oral (R-trained(2) = 0.85; R-consumer(2) = 0.96) and tactile (R-trained(2) = 0.78; R-consumer(2) = 0.79) stickiness intensity, and stickiness intensity ratings decreased with T-g of completely amorphous samples. Further, glassy samples followed a different texture trajectory (brittle-cohesive-toothpacking) than rubbery samples (deformable-tacky-enveloping). These results illuminate the dynamic perception of stickiness and support the potential of T-g to predict both stickiness intensity and texture trajectory in caramel systems. Practical Application Sensory texture is critical to consumer acceptance and challenging to measure. Reliable instrumental predictors of sensory texture aid the food scientist by providing a time-effective method for screening sample prototypes and streamlining the product development and refinement process. This study shows that the glass transition temperature (T-g) is strongly correlated to oral and tactile stickiness ratings in caramel systems. Additionally, initial physical state of the caramel samples (glassy, rubbery, or intermediate state) can predict the dominant temporal texture profile. Based on these findings, T-g shows strong promise as a metric for prediction of sensory texture profile with possible applications in confectionary and other low moisture food systems.