Use of chicken pepsin extract in the coagulation of cow, goat and camel milks for the manufacture of fresh cheese

Abstract

The objective of this work is to evaluate chicken pepsin extract (CP) in liquid and freeze- dried form, and its use in the coagulation of different types of milk in order to establish a chicken pepsin production unit in Algeria. To achieve this objective, we extracted chicken pepsin from the proventriculus. We analyzed the physical and chemical properties of CP in parallel with the cheeses obtained. The clarified CP is essentially characterized by a coagulating activity (4.95 ± 0.49) RU / ml and a coagulating strength (1/2040.81) SU. The FTIR spectra of CP show OH, CH, C = O and C-O bonds. For diffraction, we recorded the presence of AL2CaO4. The results of the effect of storage on CP indicated that the use of liquid CP extract should not exceed one week at +4°C and one month at -20°C for milk coagulation; and the cooling and freezing of CP extract mainly affect the milk coagulation time. According to the coagulating strength, the recommended volumes of CP for milk coagulation were 0.5mL (for Cow Milk) ‘CM’, 1mL (for Goat Milk) ‘GM’ and 3mL (for Camel Milk) ‘DM’. The best cheese yield with CM was 18.9% and coagulated with Freeze Dried Chicken Pepsin (FDCP). The physicochemical analyses of the six cheeses showed the highest DM and ash which were 53.3±1.2% and 8.75±0.4% respectively. The FTIR spectra of the cheeses showed the bonds (OH, CH, C=O and C-O and N-H). For diffraction, all the cheeses had an amorphous structure. The microstructure of cheeses is related to the type of milk and to LCP or FDCP. The casein network was more cohesive and more compact with FDCP. Finally, we can deduce that the use of chicken pepsin in freeze-dried form is recommended for milk coagulation and in order cow milk, goat milk and then camel milk.