Influence of Onopordum platylepis Murb. as a Vegetable Coagulant on the Production and Bioactivity of Peptides in Murcia al Vino Cheese

The bioactive potential of dairy-derived peptides has attracted increasing interest due to their capacity to exert antioxidant and antihypertensive effects. This study investigated three artisanal cheeses manufactured with animal rennet (CTRL), Onopordum platylepis extract (OP), or a mixture of both coagulants (AR/OP) to compare their peptide profiles and associated bioactivities. Water-soluble extracts were analyzed to identify precursors and released bioactive peptides, and in vitro assays were performed to assess antioxidant activity and angiotensin-converting enzyme (ACE) inhibition. The analysis of precursors suggested a predominance of antioxidant sequences in CTRL and ACE-inhibitory precursors in OP, with AR/OP showing intermediate values. However, direct peptide identification confirmed that the AR/OP mixture produced a wider range of peptides with antioxidant activity, while OP and AR/OP exhibited similarly high levels of ACE-inhibiting peptides. These results were consistent with in vitro assays, which confirmed AR/OP as the most active sample for antioxidant potential and OP, closely followed by AR/OP, as the strongest for ACE inhibitory activity. Overall, the integration of precursor analysis, peptide identification, and experimental validation highlights the influence of the coagulant on the generation of bioactive peptides, suggesting that the use of Onopordum platylepis Murb. (O. platylepis) alone or in combination with animal rennet may enhance the functional properties of cheese.