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Partial purification and characterization of milk-clotting enzyme extracted from Withania coagulans fruit
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M Beigomi   , MA Mohammadifar * , M Ghods Rohani , M Hashemi , M Valizadeh |
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Abstract: (10499 Views) |
| Background and objective: Numerous attempts have been made to replace calf rennet with other milk-clotting proteases because of limited supply and high prices of calf rennet. Fruit of Withania coagulans (solanaceae), a medicinal plant rich in milk-cloting proteases, have been traditionally used in the south of Iran as a plant coagulant for cheese-making. No systematic study on the characterization of W. coagulans milk-clotting enzyme has been conducted so far. The purpose of this study was to extract, partially purify and characterize the milk-clotting enzyme from W.coagulans.
Materials and methods: An enzyme extract was prepared from the fruit of W. coagulansusing using a 0.85% NaCl solution, and the milk-clotting activity and characteristics of the milk-cloting enzyme (effect of temperature, pH, enzyme concentration and thermal stability) were assessed. The extract was partially purified, and the molecular mass of the crude extract and the fractions with the highest milk-clotting activity were determined by SDS- PAGE.
Results: The optimal temperature and pH for the enzyme were 70˚C and 4, respectively. Partial purification showed that the milk-clotting activity of the enzyme purified with 50% ammonium sulphate was greater than samples purified with other ammonium sulphate solutions at other concentrations. The molecular mass of this fraction using SDS-PAGE showed two bands, namely, 66 and 29 kDa. An important characteristic of the enzyme was its excellent thermal stability it retained 74% of its milk-clotting activity at 60˚C for 30 min.
Conclusion: It seems that W. coagulans proteases can be used as a suitable source of enzyme in the dairy industry as an alternative clotting agent.
Keywords: Withania coagulans, Extraction, Partial purification, SDS-PAGE |
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| Keywords: Withania coagulans, Extraction, Partial purification, SDS-PAGE |
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Full-Text [PDF 643 kb]
(3441 Downloads)
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Article type: Research |
Subject:
Food Science
Received: 2013/10/28 | Accepted: 2013/11/19 | Published: 2013/11/19
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