A procedure was developed for measuring residual rennin activity in curd extracts and whey. A sensitive substrate at pH 5.8 was prepared by mixing 6 grams of low-heat nonfat dry milk in 500 milliliters buffer containing 0.05 molar cacodylic acid, 0.02 molar calcium chloride, and 0.012 molar triethanolamine, and storing it at 2 degrees centigrade for 18 hours. Two milliliters of whey or curd extract were inoculated into 25 milliliters of substrate at 30 degrees centigrade. The coagulation time was measured and compared to that induced by 2 milliliters of a known rennin concentration added at the same time to identical substrate. Recovery of activity was determined by adjusting milk samples to pH 5.20 and coagulating them with a known concentration of rennin. The clot was broken by agitation and the curd separated from the whey by centrifugation. Activities accounted for in the curd and whey amounted to 91±1.6 per cent the activity added to the milk. Maximum release of activity from curd was achieved by diluting the curd 1:15 with water and adjusting the pH to 6.80. Inclusion of curd particles with the inoculum decreased the sensitivity of the substrate.
| Identifer | oai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-6127 |
| Date | 01 May 1971 |
| Creators | Reyes, Jorge |
| Publisher | DigitalCommons@USU |
| Source Sets | Utah State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | All Graduate Theses and Dissertations |
| Rights | Copyright for this work is held by the author. Transmission or reproduction of materials protected by copyright beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owner. Responsibility for any use rests exclusively with the user. For more information contact digitalcommons@usu.edu. |
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