Utilisation de la pepsine de poulet et de la ficine du figuier comme agents coagulants du lait.

Abstract

The aim of the present work is the characterization of extracted ficin from fig latex (Ficus carica) and the extracted pepsin from chicken proventriculus. This characterization mainly targeted the determination of activity and coagulant force. Also, the proteolytic activity and the types of interactions involved in the formation of gels in comparison with animal rennet studied. On the other hand, a test of the use of ficin and pepsin in the coagulation of the milk as a substitute for rennet in the preparation of a soft cheese type "Camembert" was performed. The main results obtained have shown that the extract of ficin exhibits coagulant activity of 121,69 UP and a force coagulant 1/42059. For chicken pepsin coagulant activity is 18.61 UP and the force coagulant 1/6041. In addition, the proteolytic activity was estimated at 469.7 μg and 117 μg tyrosine equivalent per ml of enzyme for ficin and pepsin. The study of the interactions involved in the formation of ficin and pepsin gels showed the preponderance of hydrophobic bonds, followed by hydrogen bonds and the calcium bonds. The soft cheeses type "Camembert" obtained with ficin, or pepsin presented large similarities on the map color, smell and taste compared to control cheese (microbial substitute). Nevertheless, some differences were found including the level of bitterness and texture for both enzymes. We report on the other hand, that cheese yields are 33.25% and 37.82% in the case of ficin and pepsin respectively. These yields are relatively low compared to the control cheese estimated at 38.41%. These results reflect the ability to override the rennet by ficin and/or chicken pepsin in the cheese manufacturing. However, this study deserves to be extended to other cheeses and pursued for reason to improve yields and cheese quality.