Upcycling Blackberry Juice Pomace into Fruit Beer: Effects of High Pressure Processing on Polyphenols, Colour, Volatile Profile and Sensory Analysis

The integration of fruit by-products into brewing represents a promising strategy to enhance sustainability within the beverage sector. This study evaluates the use of dried blackberry (Rubus fruticosus L.) juice pomace, either untreated or pre-treated by High-Pressure Processing (HPP), as an ingredient in fruit beer production. A portion of the blackberry pomace was dried at 50 °C and incorporated into a beer formulation named “control beer” (CB), while another portion of the blackberry pomace was subjected to HPP at 600 MPa for 3 min, dried at 50 °C and incorporated into a beer formulation named HPPB. The beers were analysed for their physicochemical parameters, colour properties, total phenolic content, antioxidant capacity (UV–Vis and EPR), and volatile composition (HS-SPME-GC-MS). A trained sensory panel (n = 8) assessed descriptive attributes. HPP significantly affected the colour of the dried pomace and resulted in beers with higher lightness (L*) but lower redness (a*) and total phenolics. CB exhibited higher antioxidant capacity, whereas HPPB showed increased levels of fruity esters. Sensory analysis confirmed that HPPB was perceived as significantly more fruity in both orthonasal odour and flavour (p < 0.05). No significant differences were detected in beer oxidative stability by EPR. These findings demonstrate that HPP-treated blackberry pomace can modulate the sensory profile of fruit beers despite reducing phenolic retention, and that upcycled by-products can support the development of sustainable, specialty beers.