In vitro digestibility, peptide profile, and bioactivities of water lentil (duckweed) protein compared to commercial protein isolates

Water lentils (duckweeds) are a promising protein source, however their digestibility and potential to release bioactive peptides remain underexplored. This study investigated, for the first time, the in vitro digestibility of proteins from water lentil protein concentrates (WLPCs) and their associated by-products obtained through chemical or electrochemical purification, in comparison with the initial native water lentil powder (IP) and commercial protein isolates (egg white, whey, and soy), using the INFOGEST protocol. Following the intestinal phase of the digestion, WLPCs exhibited moderate digestibility, likely due to protein denaturation during extraction, whereas the bioaccessible fraction (∼38 %) of IP showed high digestibility. Peptide profiling further revealed that IP produced a more diverse peptide pool than WLPCs and their by-products. Regarding bioactivity, intestinal digestate supernatants from IP, whey and soy protein isolate showed the strongest ACE inhibition, while WLPCs exhibited the highest DPP-IV inhibition. These findings indicate that water lentil protein purification does not necessarily improve digestibility, but they confirm the potential of water lentil proteins as a valuable source of bioactive peptides.