Journal of the Bath and West of England Society and Southern Counties Association - Fourth Series Vol. I, 1890-91

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1891 edition. Excerpt: ...Germans employ this imperfect method of analysis they term the result arrived at " Rohprotein," that is "crude protein," but English analysts are unfortunately not in the habit of giving this warning. It would be better if the calculated result from the total nitrogen present was always designated as "nitrogenous substance," and not as "albuminoids." The present state of matters is a survival of an old practice. Formerly no method was known for determining the true albuminoids in a food, nor were chemists aware that amides were always present in certain descriptions of food. Now analysts have good methods for determining the true The nitrogen of the nitrates is rarely estimated in food analyses.--Assoc. Ed. albuminoids present, but as yet they generally adhere to the old and easy method of determining the total nitrogen, and then multiplying its quantity by six and a quarter. It is certainly surprising that with good methods in their hands so little has been done by chemists to determine the amount of true albuminoids in various foods, and that so little use has hitherto been made of the facts which have been ascertained. It must always be borne in mind that the German ratios are still based on the quantities of total nitrogen; they are therefore in many cases not "albuminoid ratios," but simply the ratios of nitrogenous to non-nitrogenous matter. The error we have pointed out occurs, however, only with certain classes of food. Ripe seeds of all kinds contain only a small proportion of amides, unless germination has commenced. Ripe straw contains also but a small proportion. On the other hand, all green fodder crops, roots and tubers, contain a considerable amount of amides, and nitrates...