Milk-clotting and hydrolytic activities of an aspartic protease from Salpichroa origanifolia fruits on individual caseins

• Published in: International journal of biological macromolecules Vol. 192; pp. 931 - 938
• Main Authors: Rocha, Gabriela Fernanda, Cotabarren, Juliana, Obregón, Walter David, Fernández, Graciela, Rosso, Adriana Mabel, Parisi, Mónica Graciela
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.12.2021
• Subjects: Animals; Aspartic Acid Proteases - chemistry; Aspartic Acid Proteases - isolation & purification; Bioactive peptides; Casein; Caseins - chemistry; Cheese - analysis; Chemical Phenomena; Enzyme Activation; Fruit - chemistry; Fruit - enzymology; Hydrolysis; In silico analysis; Kinetics; Milk - chemistry; Milk-clotting activity; Plant Extracts; Salpichroa origanifolia; Solanaceae - chemistry; Solanaceae - enzymology; Structure-Activity Relationship; Salpichroa origanifolia; Milk-clotting activity; Casein; Bioactive peptides; In silico analysis
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2021.10.004

In recent years, many attempts have been made to find new plant proteases to make artisan cheeses. The global increase in cheese consumption, together with a lower supply and increasing cost of calf rennet, religious factors (Islam and Judaism) and food choices (vegetarianism) have led to the search for suitable rennet substitutes for milk clotting. This study describes the milk-clotting and hydrolytic activities of an aspartic protease from Salpichroa origanifolia fruits (SoAP) on individual caseins to explore its potential use as an alternative to animal rennet. The milk-clotting index obtained for SoAP was 8.4 times lower than that obtained for chymosin. SoAP showed a higher degree of hydrolysis on α-casein than on the other fractions under the proposed conditions. RP-HPLC, mass spectrometry analyses and sequencing of the hydrolysates allowed identifying five peptides from α-casein, one peptide from β-casein, and three peptides from k-casein. In silico analysis showed that the peptides identified may display a wide variety of potential biological activities. These results demonstrate the possibility of using SoAP for the manufacture of new types or artisan cheeses, with the simultaneous added value of the potential health-promoting benefits of the bioactive peptides generated during the hydrolysis. •An aspartic protease, named SoAP, was purified from Salpichroa origanifolia fruits.•SoAP showed good caseinolytic and milk-clotting activities.•The milk-clotting index of SoAP was like other plant proteases.•SoAP hydrolysed α-casein more effectively than β-casein and κ-casein.•Five peptides from α-casein, one from β-casein and three from k-casein were identified.•A wide variety of potential biological activities were predicted by in silico analysis.