Experimental study on the continuous production of velvet bean-based bioactive peptides in a membrane reactor and bioactivity mapping

This study investigates the continuous production of bioactive peptides from fermented velvet bean (Mucuna pruriens) using a cost-effective enzymatic membrane reactor. The optimal operating conditions for continuous hydrolysis were residence time of 9 h, enzyme-to-substrate ratio of 10%, and the use of a 5-kDa PES membrane for separation. The resulting permeate exhibited notable antioxidant activity with DPPH and FRAP assay values of 0.28 and 0.12 mg AEAC/mL, respectively, and an angiotensin-converting enzyme (ACE) inhibition of 83.28%. Further fractionation of the permeate with a 2-kDa membrane led to increased antioxidant activity and ACE inhibition, with resulting half maximal inhibitory concentration (IC50) values of 7.6 and 0.6 μg protein/mL, respectively. Liquid chromatography-mass spectrometry was used to identify peptide sequences from the <2-kDa fraction, which were matched with the BIOPEP-UWM™ database. The results revealed that the fermented velvet bean peptides were predominantly dipeptidyl peptidase (DPP)-4 inhibitors and ACE inhibitors. The combination of a stirred tank reactor and membrane separation has the potential to enable the continuous production of bioactive peptides from velvet bean through the use of a freely suspended enzyme system. This reactor design offers an alternative solution to the existing delay in commercializing bioactive peptides, by (i) simplifying the industrial process development for continuous bioactive peptide production, (ii) eliminating the need for enzyme immobilization, and (iii) eliminating batch-to-batch variability in product quality and unproductive time associated with batch-wise production.