Screening of some Egyptian plants for milk clotting activity

Amer, A. G.; Omar, M. A.; Abdrabou, N. S.

doi:10.21608/ajar.2022.266506

Screening of some Egyptian plants for milk clotting activity

Authors

¹ Dairy Department, Faculty of Agriculture, Al-Azhar University, Cairo, Egypt.

² Dairy Department, National Research Centre, 33th El-Bohoos Str.; Dokki, Giza, Egypt.

10.21608/ajar.2022.266506

Abstract

This study was conducted to evaluate the possible presence of potent milk-clotting enzymes (MCE). Nine plants (E. millim Leave, F. elastica Leave, M. oleifera seeds, A. lebbeck seeds, A. variegata leaves, T. foenum-graecum seeds, A. Chinesis fruit, H. annuus seeds and F. vulgare seeds) were screened in order to get the most promising alternative source for potent (MCA). These results illustrated that MCA Of different extracts were dependent on plant type.The extraction of MCE from A. lebbeck seeds gave higher MCA and MCA / proteolytic activity (PA) Ratio compared to that extracted from the other plants. The aqueous extract of A. lebbeck seeds was taken as a crude enzyme source. MCE of A. lebbeck from prepared seeds dissolved in 0.1 M phosphate buffer pH 5.7 + 5% NaCl that gave the high activity in comparison to other buffers; moreover 20–40 % ammonium sulfate saturation precipitated MCE with 11.83 % yield and 6.16% purification rate. Sephadex G-100 recorded the highest specific activity (SA) and purification fold with 5.98 % yield and 9.84% purification rate. The crude and partial purified enzyme has optimal pH 6 and optimal temperature 40^oC. The thermally stability of enzyme exhibited at 30 to 40°C for 10-60 minutes. NaCl inhibited MCA for both crude and partial purified enzyme, even at low concentration (1%). CaCl2 stimulated MCA up to 30 mM. Several metal ions were stimulant on the enzyme like Cd²⁺, Mn²⁺, Ba²⁺ NH₄²⁺and Fe²⁺ while Cu²⁺, K⁺, I⁺ and Ni²⁺ were act as inhibitors.Storage at 4°C for 28 days resulted in a 3.6 and-5.3% loss in activity to both partial purified and crude enzyme, also Storage at room temperature for same days resulted in a 22.6 and 24.4% loss in activity to both partial purified and crude enzyme respectively.

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