Sokoine University of Agriculture

Optimisation of activity and storage stability of crude pepsin extracted from adult cattle Abomasa for cheese making

Show simple item record Ryoba, R. Kurwijila, L. Minja, M. Sorhaug, T. Stepaniak, L. 2017-12-18T06:18:17Z 2017-12-18T06:18:17Z 2001
dc.identifier.issn 0856 668X
dc.description Tanzania Journal of Agricultural Sciences 2001, Vol. 4(1) : 29-36 en_US
dc.description.abstract The study conducted to investigate the activity and storage stability of crude pepsin extract for use as rennet substitute in cheese processing. The conditions tested were regions of the abomasa, fresh versus dry abomasa drying methods, maceration temperatures (37oC, 24-28oC or 15oC); maceration pH 1-6 for 6 days; activation pH (pH 1-4) and clarification by centrifugation or use of chemicals. The shelf life of the extract was evaluated under storage temperatures ranging from deep freezing at -20oC refrigeration temperatures (<10 oC) and room temperature. Results showed that fundic region of the abomasa had 70.8% pepsin while the pyloric region had only 27% pepsin. Milk clotting activity (MCA) was 1978 and 1800 pepsin units per ml (PU/ml) for sun and shade-dried abomasa respectively. Concentrations of 5, 10, 15, 20, 25% NaCl gave 1845, 2189, 1596, 1021, 462 MCA respectively. Maceration at pH 3 for 3 days at 37 oC gave the highest enzymatic activity (5536 PU/ml). Clearing of the extract by centrifugation at 3000g/15 min gave an extract with 902.3 PU/ml. Clarification by use of di-sodium phosphate (Na2HSO4) gave extract of 1679.1 PU/ml. The enzyme activity of the extract stored under deep freezer temperature was sibnificantly higher (p < 0.05) than ambient and refrigeration temperatures. However, they were significantly lower (p< 0. 001) than the activity of the extract before storage. Therefore, the best pepsin extraction conditions were found to be the use of fundic region of sundried abomasa, macerated at 37oC in an extraction solution containing 5-10% salt at pH 3 for 3 days and clarified after activation at pH2 for 20 min followed by centrifugation of sediment at 3000g/15 min or by use of anhydrous disodium phosphate. The clarified extract could retain its activity for 16 weeks when stored at - 20oC in single use portions en_US
dc.language.iso en en_US
dc.subject Milk en_US
dc.subject Clotting activity en_US
dc.subject Pepsin en_US
dc.subject Cheese en_US
dc.title Optimisation of activity and storage stability of crude pepsin extracted from adult cattle Abomasa for cheese making en_US
dc.type Article en_US

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