Abstract
The comparative values of the following solvents in extracting vitamine from yeast were studied: ethyl alcohol (50, 60, 70, and 80 per cent.), methyl alcohol (60 to 70 per cent.), propyl alcohol (70 per cent.), butyl alcohol (70 per cent.), isobutyl alcohol (70 per cent.), acetone (70 per cent.), methyl ethyl ketone (70 per cent.) and acetic acid (70 per cent.). The extracts and residues were tested on pigeons and rats, and the extracts were also tested for their content of vitamine D (yeast growth), co-ferment, total nitrogen and total solids.
If inactivity of residue be taken as a criterion, then 70 per cent. alcohol has proved to be the best solvent for vitamine among the solvents used. If, however, we stress not only the activity of the extract, but also the quantiy of nitrogenous and other impurities accompanying the extract (selecting the one that gives a minimum of such impurities), then the best among the solvents is acetone.
Vitamines B and D tend to run parallel with one another, so that, as a rule, the higher the content of vitamine B, the higher in vitamine D is the extract apt to be.
The co-ferment shows no definite relation to either vitamine B or D.
On the whole, the higher the nitrogen content of the extract, the greater the percentage of total solids, and the greater the activity of the extract.
Using these solvents on rice polishings instead of on yeast, we find that 60 per cent. alcohol is better than 70 per cent.
The extracts from rice polishings seem to be particularly active when tested on rats, and, by comparison, far less so when tested on pigeons.
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