Effect of sand roasting, microwave, ultrasonic, enzymatic, and thermal treatments on the different functional properties of the cowpea milk

Plant milk alternatives are consumed all over the world and are known for their functional active components. This study investigated the effect of various physical (sand roasting, heating, pressure cooking, freezing, ultrasonics, and microwave), chemical (pH shifting, additive and salt addition), and biochemical (germination and α-amylase) treatments on the crucial functional properties of the cowpea milk (CPM). The sand-roasted sample has exhibited the maximum browning index. Foaming capacity (FC) and stability, emulsifying capacity (EC), oil absorbance and water holding capacity were examined, along with the phenolics, flavonoids and % DPPH inhibition tests were undertaken. Results indicated that the heat-treated CPM showed maximum foaming capacity (30.55%), the α-amylase-treated sample exhibited the highest emulsifying capacity (EC) (53.6%), and the germinated CPM showed the highest phenolic content (64.62 μg GAE/mL), flavonoid content (23.14 μg QE/mL), and antioxidant activity (40.8% DPPH inhibition). High-resolution mass spectrometry (HR-MS) profiling of bioactive compounds (BACs) in CPM has confirmed the formation of several key bioactive metabolites in the milk. The predominant phenolic-based metabolites identified include kaempferol, ferulic acid, gallic acid, β-ionone, and ethyl palmitoleate, with retention times (RT) ranging from 0.7 to 27 min. These findings highlighted the multifaceted functionality of CPM post-treatments, and this legume milk is a functional food that could be the best dairy replacer.