Abstract
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Article Information:
Effect of Extraction Method, Ammonium Sulphate Concentration, Temperature and pH on Milk-Clotting Activity of Solanum dubium Fruit Extract
M.O.M. Abdalla, S.E.O. Kheir and O.A.O. El Owni
Corresponding Author: Mohamed Osman Mohamed Abdalla
Submitted: 2010 December, 13
Accepted: 2011 January, 07
Published: 2011 February, 15 |
Abstract:
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Solanum dubium fruits were collected and used as a plant source for extracting milk coagulating
enzymes. The enzyme was extracted by four methods and the activity of each extract was determined. Solanum
dubium fruits were kept at 4 and 37ºC for five months, while aqueous extracts of the Solanum dubium fruits
were kept at 4 and 37ºC for three months. The crude extract of Solanum dubium fruit was precipitated by
ammonium sulphate using different concentrations (0-90%). Partial characterization of the milk coagulant was
carried out. The results showed that maximum milk-activity (p<0.001) was obtained from Solanum dubium fruit
extracted with freeze-drying. The milk-clotting activity significantly decreased (p<0.001) from 3.65 U/mL
when Solanum dubium was extracted with 1% NaCl in distilled water to 1.74 when Solanum dubium was
extracted with 5% NaCl. The loss in activity of Solanum dubium fruits stored in liquid and solid forms
increased significantly (p<0.05) at room temperature compared to refrigerator storage. The saturation with
ammonium sulphate (60%) gave higher milk- clotting activity (5.03 mg/mL) and protein content. The partially
purified Solanum dubium fruit extract had the highest activity at 70ºC and pH 10. Twenty five milliliters
(25 mL/50 L milk) of a partially purified Solanum dubium fruit extract was recommended for cheese making.
Key words: Extraction method, milk-clotting activity, Solanum dubium, temperature, , ,
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Cite this Reference:
M.O.M. Abdalla, S.E.O. Kheir and O.A.O. El Owni, . Effect of Extraction Method, Ammonium Sulphate Concentration, Temperature and pH on Milk-Clotting Activity of Solanum dubium Fruit Extract. Advance Journal of Food Science and Technology, (1): 40-44.
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ISSN (Online): 2042-4876
ISSN (Print): 2042-4868 |
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