The purpose of this study was to determine if size exclusion chromatography could be used to separate casein micelles from whey proteins for a rapid, direct test to measure percent casein in milk. A size exclusion chromatography column was developed for the separation having dimensions 100 by .4 cm. Packing material selected was glycophase coated porous glass supports. A Beckman DU-8B spectrophotometer monitored the casein and whey protein peaks as they eluted and a Tektronix 4052 computer accepted data points every 4 sec, storing these on tape. Absorbances and areas of each peak were used in the evaluation of samples. Treatments of temperature, pH and calcium addition were performed on a commingled milk sample from Utah State University Dairy Laboratory. It was determined that addition of calcium and pre-warming to 40 C before injection is important for good separation. Several samples of milk from individual cows were run through the column and parameters obtained. For each sample, percent casein was measured using the standard method of acid precipitation and Kjeldahl nitrogen determination. Percent casein was then estimated using area and absorbance of each casein peak from the elution plots of milk from individual cows. A regression line of predicted vs actual percent casein resulted in a correlation coefficient (r) of .92.
| Identifer | oai:union.ndltd.org:UTAHS/oai:digitalcommons.usu.edu:etd-6401 |
| Date | 01 May 1983 |
| Creators | Carpenter, Robert N. |
| 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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