Modification of tuna (Katsuwonus pelamis) hydrolysates with galangal active ingredients: Enhancing flavor and functional properties.

Marine protein hydrolysates hold great promise for functional foods, but undesirable flavors often limit their application. This study aimed to enhance both the sensory and functional properties of tuna (Katsuwonus pelamis) hydrolysates by introducing galangal (Alpinia officinarum) active ingredients. Eight preparation routes were designed to generate galangal-flavored peptide-rich bases (GPBs) with different addition strategies. GPBs contained flavonoids and polysaccharides derived from galangal, and exhibited stronger xanthine oxidase inhibitory (XOI) activity compared with tuna hydrolysates, while preserving tuna-derived peptide sequences associated with antihypertensive and other bioactivities. Volatile profiling and sensory evaluation confirmed a reduction in fishy off-odor and bitterness, accompanied by characteristic gingery and caramel-like notes. Route S2, in which tuna and galangal were hydrolyzed separately before alkaline extraction of the mixture, was identified as the optimal preparation strategy, achieving a favorable combination of flavor improvement, retention of peptides associated with potential bioactivities, relatively higher polysaccharide and flavonoid contents, and enhanced XOI activity. Simulated digestion and colonic fermentation demonstrated that GPB prepared by route S2 modulated gut metabolites differently from tuna hydrolysates, suggesting altered gut metabolic profiles compared with tuna hydrolysates. These results reveal that galangal active ingredients effectively enhance both flavor and functional potential of tuna hydrolysates, providing a practical approach for developing peptide-based functional foods with improved sensory attributes.