ISHS Acta Horticulturae 501: II WOCMAP Congress Medicinal and Aromatic Plants, Part 2: Pharmacognosy, Pharmacology, Phytomedicine, Toxicology
PRESENCE OF MILK CLOTTING PROTEINASES IN CYNARA SCOLYMUS L. CV. GREEN GLOBE (ASTERACEAE) |
| Authors: | B. Llorente, C. Brutti, C. Cimino, S. Vairo Cavalli, C. Natalucci, N. Caffini |
| Keywords: | Artichoke, Aspartic proteinases, Asteraceae, Cynara scolymus cv. Green Globe, Milk clotting enzymes |
| Abstract:
Proteolytic enzymes are widely employed in food industry, including cheese manufacture. The coagulant most widely used for cheese making is animal rennet, which contains chymosin, an aspartic protease responsible for milk clotting. The flowers of cardoon (Cynara cardunculus L.) are traditionally used in the Mediterranean region for cheese making. Different species are described for the genus Cynara, but only C. cardunculus is referred to be used in cheese making. The present paper deals with the presence of milk clotting activity in different organs of the artichoke (Cynara scolymus L., cv. Green Globe). The presence of proteinases has been investigated by determining the proteolytic and milk clotting activities of crude extracts of different parts of the inflorescence in various stages of development, as well as of leaves and roots. Although all the preparations showed a certain extent of proteolytic activity, only those of adult leaves, pappus, and immature and mature flowers were able to clot milk. The extracts of the violet parts of mature flowers (violet styles and stigmas) exhibited optimum activity at acid pH values (90% of maximum activity at pH 3.5–5.0) which was strongly inhibited by pepstatine A, suggesting the presence of aspartic proteinases. This extract had low thermal stability at temperatures above 45°C. Isoelectric focusing followed by zymograms on haemoglobin at pH 4.0 reveals the presence of several proteolytic components (pI range 5.0–5.5). Proteolytic activity is absent in zymograms from gel electrophoresis made in denaturating-non-reductive conditions (SDS-PAGE without  -mercaptoethanol), suggesting a polymeric nature for the active fractions.
| |
Download Adobe Acrobat Reader (free software to read PDF files) | |
