Innovative Craft Beers Added with Purple Grape Pomace: Exploring Technological, Sensory, and Bioactive Characteristics

Abstract

Purple grape juice produces a significant amount of grape pomace (GP) as a by-product, which can be reused as a raw material in producing craft beers with bioactive properties. The objective of this study was to produce craft beers with the addition of GP during the fermentation process to evaluate the incorporation of bioactive compounds, aiming at using a by-product generated in the production of grape juice. Craft beer was produced, incorporating GP at concentrations of 1%, 5%, and 10% (w/w), and the physicochemical, technological, bioactive, and sensory properties were evaluated. The beers with the highest concentrations of GP (10% w/w) exhibited higher bioactive concentrations, including phenolic compounds (308 mg GAE/L), flavonoids (0.05 g of quercetin/L), anthocyanins (754.6 mg cyanidin-3-glucoside/L), and antioxidant capacities, as measured by DPPH (1878.2 µM Trolox/L), ABTS (4294.5 µM Trolox/L), and FRAP (844.7 mg ascorbic acid/L) methods. Adding GP promoted lower brightness (62.2) and intensified the a*, b*, and chroma parameters (18.0, 10.1, and 20.6, respectively), with the pigments of GP contributing to changes in the color parameters. However, increased sedimentation was observed under both conditions analyzed (4 °C and 25 °C), due to the higher presence of particulate matter from GP (3.4% and 3.7%, respectively). In general, for sensory analysis, while the knowledge of beneficial effects did not significantly change emotional responses, there were distinct emotional profiles associated with different beer samples. Utilizing GP for the bioactivation of beer is a positive approach to enhance its overall properties and an effective way to address issues related to the disposal of this by-product.

Keywords

• by-product
• grape pomace
• bioactivation
• phenolic compounds
• beverages