STUDIES ON ACCELERATION OF RAS CHEESE RIPENING USING PROTEOLYTIC ENZYMES
ADEL MAHMOUD MOHAMED KHOLIF;
Abstract
Adel Mahmoud Mohamed Kholif: Studies on Acceleration of Ras Cheese Ripening Using Proteolytic Enzymes. Unpublished Ph.D. Thesis, Department of Food Science, Faculty of Agriculture, Ain Shams University, 2017.
Milk clotting enzyme (MCE) from Fruit Seeds of Solanum elaeagnifolium plant, which has the capacity of forming milk curds was obtained by fractional precipitation with ammonium sulphate. The extracted enzyme was purified by using sequential chromatographic technique of the most active fraction on Sephadex G 200 to 4.21 folds with 4 % recovery.
Molecular weight of the enzyme was found to be 28 kDa, and its optimum temperature was 40 °C. The enzyme activity was stable at 40 to 60 °C with incubation times from 10-30 min. The enzyme showed the pH optima of 5.9, and quite stable in broad pH range of 4.0 to 6.5.
Effect of calcium chloride (CaCl2) and sodium chloride (NaCl) at a concentration of 20 mM and 2 % gave the highest relative activity of the purified MCE about 1.31 and 1.10 fold, respectively. At a concentration of 10 mM and 1 % the enzyme gave the highest relative activity to proteolytic about 1.08 and 1.05 fold respectively.
The metal ions at 1 mM Zn2+, Ba2+, EDTA, Mg2+, Mn2+ were activators, whereas Fe2+, Mg3+, Ni2+ were inhibitors of the purified MCE. The Cu2+ at 1 mM was most effective stimulator, 5 mM Ba2+ was activator, whereas Zn2+, EDTA, Mg2+, Cu2+, Mn2+, Fe2+, Mg3+, Ni2+ at 5 mM were inhibitors. The Mg3+, Ni2+ at 5mM were the most inhibitors of the purified MCE and showed a typical hyperbolic velocity saturation curve with Km value of 0.0399 % with skim milk as a substrate.
Upon storage of the purified enzyme for 15 days at refrigerator temperature and room temperature, it retained 90.39 % and 75.34 % of MCA respectively.
Milk clotting enzyme (MCE) from Fruit Seeds of Solanum elaeagnifolium plant, which has the capacity of forming milk curds was obtained by fractional precipitation with ammonium sulphate. The extracted enzyme was purified by using sequential chromatographic technique of the most active fraction on Sephadex G 200 to 4.21 folds with 4 % recovery.
Molecular weight of the enzyme was found to be 28 kDa, and its optimum temperature was 40 °C. The enzyme activity was stable at 40 to 60 °C with incubation times from 10-30 min. The enzyme showed the pH optima of 5.9, and quite stable in broad pH range of 4.0 to 6.5.
Effect of calcium chloride (CaCl2) and sodium chloride (NaCl) at a concentration of 20 mM and 2 % gave the highest relative activity of the purified MCE about 1.31 and 1.10 fold, respectively. At a concentration of 10 mM and 1 % the enzyme gave the highest relative activity to proteolytic about 1.08 and 1.05 fold respectively.
The metal ions at 1 mM Zn2+, Ba2+, EDTA, Mg2+, Mn2+ were activators, whereas Fe2+, Mg3+, Ni2+ were inhibitors of the purified MCE. The Cu2+ at 1 mM was most effective stimulator, 5 mM Ba2+ was activator, whereas Zn2+, EDTA, Mg2+, Cu2+, Mn2+, Fe2+, Mg3+, Ni2+ at 5 mM were inhibitors. The Mg3+, Ni2+ at 5mM were the most inhibitors of the purified MCE and showed a typical hyperbolic velocity saturation curve with Km value of 0.0399 % with skim milk as a substrate.
Upon storage of the purified enzyme for 15 days at refrigerator temperature and room temperature, it retained 90.39 % and 75.34 % of MCA respectively.
Other data
| Title | STUDIES ON ACCELERATION OF RAS CHEESE RIPENING USING PROTEOLYTIC ENZYMES | Other Titles | دراسـات على إسراع تسوية الجبن الراس باستخدام الإنزيمات المحللة للبروتين | Authors | ADEL MAHMOUD MOHAMED KHOLIF | Issue Date | 2017 |
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