Production and characterisation of dual-function antioxidant and anti-inflammatory peptides from edible bird’s nest (EBN) protein hydrolysates

Edible bird’s nest (EBN) is a high-protein source that holds the potential for the development of hydrolysates with valuable health benefits. This research aimed to produce natural antioxidant and anti-inflammatory hydrolysates (EBNH) derived from EBN protein through enzymatic hydrolysis. EBN protein was digested using three proteases (alcalase, flavourzyme and trypsin). The alcalase-generated EBNH showed higher peptide content, a favourable degree of hydrolysis and desired bioactivities. Response surface methodology, including single-factor design, Plackett-Burman design, and Box-Behnken design, was adopted to optimise the alcalase hydrolysis conditions. Statistical results confirmed the adequacy of the models in maximising the antioxidant and anti-inflammatory activities of EBN at a 95% confidence level. Under the optimised conditions (enzyme/substrate ratio (E/S ratio) of 2% (w/w), hydrolysis temperature of 55 °C, and pH 7), EBNH with antioxidant and anti-inflammatory activities of 64.36% and 37.99% were produced, respectively. The optimised EBNH remarkably improved the antioxidant activity by 1.58-fold and the anti-inflammatory activity by 2.0-fold compared to the unhydrolysed EBN protein. Liquid chromatography-tandem mass spectrometry analysis characterised 35 peptides in EBNH, which were categorised into 9 groups with various functional properties, including antioxidant, anti-inflammatory, antihypertensive, anti-diabetic, neuroprotective, immunomodulatory, anticancer, and antiviral activities. The simulated gastrointestinal digestion had minimal impact on the antioxidant activity of EBNH but partially reduced its anti-inflammatory activity (from 36.42 to 16.15%). Overall, EBNH holds promise as a potential food product with good antioxidant and anti-inflammatory activity.