Separation of the Proteolytic Enzymes from Fig Tree Latex and its Utilization in Gaziantep Cheese Production

Abstract

In this study ammonium sulphate fractionation, gel filtration and ion-exchange chromatography methods were applied to separate proteolytic enzymes from the milk clotting enzyme of fig tree latex. The active fractions were determined by measuring milk-clotting activity and casein-splitting activity. Reconstituted skim milk powder and α-casein were used as substrates. A broad peak which has a maximum milk-clotting to casein-splitting ratio of 4.89 was obtained. Several active fractions were obtained by ion-exchange chromatography which had high milk clotting to casein splitting ratios: 4.02:1, 3.78:1, 3.76:1, 4.00:1 and 3.57:1 respectively. The suitability of milk-clotting enzymes from fig latex for the production of Gaziantep cheese was tested. Comparative laboratory tests of cheese-making show similarities between calf rennet and enzymes obtained by ion-exchange chromatography. The results of triangle tests indicated that the difference between Gaziantep cheese made with rennet and enzyme preparation obtained from ion-exchange chromatography, was not significant (P < 0.05). Organoleptic tests showed that there was no significant difference in acidity, bitterness, creaminess, off-flavour and graininess with the LSD method (P < 0.05). It was concluded that fig tree latex is suitable as a chymosin substitute, and could be used in Gaziantep cheese production.