Grape pomace (i.e., the residual skins, seeds, and pulp left after vinification) retains up to 70% of the fruit’s original phenolic compounds and is also rich in dietary fiber. As such, because this by-product is generated in large quantities worldwide and its disposal is both technologically problematic and costly, reusing it as a food ingredient could simultaneously mitigate environmental burdens, lower winery waste-management expenses, and enhance the nutritional profile of fortified foods. In this context, this study investigated the nutritional enrichment of dark chocolate by incorporating flour produced from red (cv. Syrah) and white (cv. Arinto) grape pomace at three levels (5, 10, and 15% w/w). Formulated chocolates and controls were manufactured under industrial tempering conditions and subsequently analyzed for protein, lipids, sugars, dietary fiber, total phenolic content, antioxidant capacity (DPPH and ORAC), color, texture, and consumer perception (hedonic test). All fortified samples showed higher fiber and antioxidant activity than the control, with “White_15” showing higher fiber content (43.1%) and “Red_5” for ORAC (69,483 µmol TE/100 g) and DPPH (6587 µmol TE/100 g). Dietary fiber showed an increase in content with the increase in grape pomace incorporation, regardless of the type (red or white). Texture softening was observed in all fortified chocolates independently of the incorporation level or type (red or white). Principal Component Analysis (PCA) and hierarchical clustering confirmed clear separation between control and fortified chocolates based on the parameters analyzed. Sensory evaluation with untrained panelists revealed good overall acceptability across all formulations. These findings demonstrate that grape pomace flour can be effectively valorized as a functional ingredient in dark chocolates, supporting circular economy practices in the wine and confectionery sectors while delivering products with enhanced health-promoting attributes (nutritional and antioxidant).

The sensorial perception of dark chocolate has been studied and is commonly related to cocoa varieties’ post-harvest or manufacturing process. Although physical and chemical changes during the transformation of cocoa into chocolate are known, there is still a gap concerning the impact of heat transfer on sensory evaluation. This work aimed to apply experimental measurements and numerical simulations in a comparative study of the thermal behaviour of dark chocolate during refrigeration and evaluate its impact over physical properties and sensory evaluation. Temperature presented an initial phase with high cooling rate, shorter at 10 °C due to the higher temperature difference. After, a steady phase was observed at 10 °C, followed by a temperature decrease until 8000 s. The behaviour at 25 °C did not present such plateau, increasing from 27.1 °C to 27.5 °C, a consequence of the dissipation of latent heat during phase transition and the short temperature gradient. Numerical simulations were more correlated to experimental data at 25 °C, presenting a temperature difference < 2 °C. The instrumental evaluation of appearance presented a higher luminance of chocolate surface at 25 °C cooling temperature, which may indicate a higher propensity for occurring fat bloom during storage. Sensory evaluation revealed no significant differences on appearance, texture, and flavour/aroma between cooling at 10 °C and 25 °C.