Functional and conformational properties of proteolytic enzyme-modified potato protein isolate

BACKGROUND Potato protein hydrolysates (PPHs) were preparedwith Alcalase on intact potato protein isolates (PPI), with differenthydrolysis times (0.5-4 h), and functional and conformational properties of resultant hydrolysates were investigated. RESULTS The degree of hydrolysis changed during incubation. Peptide bond cleavage increased and hydrolysis progressed rapidly. Gel electrophoresis showed that, by increasing the hydrolysis time, peptides with an apparent molecular weight below 20 kDa increased. It also revealed that, among potato protein components, patatin was more sensitive to Alcalase (R) hydrolysis than protease inhibitors. Enzymatic hydrolysis significantly enhanced the solubility and foam capacity of PPHs, but impaired foam stability (P < 0.05). Limited enzymatic hydrolysates (0.5PPH) at the interface improved the emulsion activity and stability index. These emulsions also had the smallest z-average and polydispersity index and showed the highest zeta potential. Fourier-transform infrared spectrometry (FTIR) analysis indicated extensive disruption of hydrogen bonds in PPHs, besides augmentation of alpha-helices and beta-turns, and a decline in the beta-sheets in the secondary structure of the PPHs was shown. CONCLUSION Potato protein isolate, especially 0.5PPH, has good functional and conformational properties. Overall, our results provide new insights into the use of potato protein hydrolysates as a functional food component in the food industry. (c) 2019 Society of Chemical Industry