HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wohlt, J. E. Articles by Hoover, W. H. Search for Related Content PubMed Articles by Wohlt, J. E. Articles by Hoover, W. H.

Measurement of Protein Solubility in Common Feedstuffs

Animal and Veterinary Sciences Department, University of Maine, Orono 04473

ABSTRACT

Percent total soluble nitrogen of casein and soy protein (25 mg nitrogen/100 ml solvent) was determined at three pH's (5.5, 6.5, and 7.5) over four intervals (30, 60, 90, and 120 min) and in two solvents at 40 C. A comparison of means (46 vs. 47%) showed that solubility in autoclaved rumen fluid was significantly less than in mineral buffer. As pH increased from 5.5 to 7.5, there was an increase in mean solubility from 27 to 57%. No differences in solubility were found between pH 6.5 and 7.5 regardless of solvent or protein. With regard to extraction time, solubility did not differ between solvents at 60 min.

By procedures developed in this study, total soluble nitrogen was determined in various feedstuffs (25 mg feed nitrogen/100 ml solvent) in mineral buffer at pH 6.5 for 60 min. Solubility ranged from 3 to 93%. Feeds were grouped as to major protein fractions and amount of processing. Feeds whose major protein fractions were composed primarily of albumins and globulins had a higher solubility (32% unprocessed and 42% processed) than those composed primarily of prolamins and glutelins (25% unprocessed and 18% processed).