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 Process- ing (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 per- ceived 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.