Papain Hydrolysates of Lupin Proteins with Antioxidant, Antimicrobial, and Acetylcholinesterase Inhibitory Activities

Dietary proteins are no longer just nutritional ingredients in our food. During hydrolysis, some of the released peptides may possess properties that favor the health of the human body. In our study enzymatic hydrolysis of lupin proteins was performed using papain. Three enzyme-to-substrate ratios were set for three different duration times. The SDS-PAGE of the samples was performed. Each hydrolysate was studied for the degree of hydrolysis (DH), acetylcholinesterase (AChE) inhibitory, antimicrobial, and antioxidant activities (AOA, according to four spectrophotometric methods). The DH varied from 9.06 +/- 0.20 to 27.97 +/- 0.37%. According to the results, the best AOA was measured by the ABTS method (from 0.76 +/- 0.03 to 1.15 +/- 0.46 M TE/100 g protein). All the hydrolysates displayed AChE inhibitory activity (IC50), which varied between 155.58 +/- 1.87 and 199.63 +/- 0.41 mg/g protein. To the best of our knowledge, this is the first report of the acetylcholinesterase inhibitory activity of lupin protein hydrolysates. In conclusion, lupin proteins prove to have a high potential to serve as a source of bioactive peptides.