Yassmin Ghassan Abd Alhamed1* and Ramadan Suliman Atra 1

¹ Department of Food Engineering, Faculty of Chemical and Petroleum Engineering, Homs University, Homs Syria.

(*Corresponding author: Yassmin Abd Alhamed, Email:  yasminabdulalhamid@gmail.com, Tel: 0994299379)

Received: 18/ 8/ 2025      Accepted: 14/ 10/ 2025

Abstract: 

Chicken pepsin extracted from proventriculi represents a promising alternative to animal rennet, as studies have demonstrated its effectiveness in milk coagulation and the production of cheeses with quality comparable to traditional rennet. Its utilization also contributes to expanding sources of milk-clotting enzymes and meeting the needs of the cheese industry. This study focused on extracting chicken pepsin from the kaolin-coated membrane of the chicken proventriculus using two different solutions: the first containing 1% boric acid and 10% sodium chloride (pH = 5.51), and the second containing 3% boric acid and 10% sodium chloride (pH = 5.02). The results indicated that the first solution provided superior extraction efficiency. Two preservation methods for the enzyme extract were evaluated: vacuum drying (at 35 and 40 °C, 200 mbar) and freeze-drying at 0.1 mbar, followed by storage at room temperature (25 °C) for 4 months and 2 weeks. Results showed that freeze-drying was the most efficient preservation method, achieving higher residual coagulation activity (80.59% and 53.09%) at the end of the storage period. Moreover, storage duration, extraction solution pH, and drying temperature significantly affected the enzyme’s milk-clotting activity (P ≤ 0.05).

Keywords: Chicken pepsin enzyme, extraction, vacuum drying, coagulation activity, clotting time, freeze-drying.

 Full paper in Arabic: PDF