Abstract
Occasional allusion is made to the rôle of “protective colloids” in physiological processes. Commonly these are evaluated according to their “gold number”, on which basis gelatins are conceded to be particularly powerful protective colloids (gold number 0.005 to 0.01). 1
In connection with a series of digestion experiments we have had an opportunity to observe the influence of peptic digestion on the protective power of gelatin, as measured by gold number. These included both in vitro peptic digestion experiments, and observations upon gastric samples removed periodically from human subjects following gelatin meals.
The beaker experiments indicated that digestion with pepsin has no influence on the protective colloid value of gelatin. That digestion actually occurred was determined by precipitation with trichloracetic acid and subsequent determination of non-precipitable nitrogen, as well as by observing the gradual loss of viscosity and power to form gels. The digestion of a 10 per cent gelatin solution furnishes a striking example. The blank upon cooling set to a firm gel, while the digested mixture remained completely fluid. The gold number of the unchanged gelatin was 0.007, while that of the digested gelatin was 0.006. Evidently the peptic digestion products of gelatin possess essentially the same protective value as does the original gelatin.
In the in vivo experiments, the protective value of the gastric contents suffered a progressive decrease, due to the dilution caused by secretion and evacuation. However, the rate of diminution of protective colloid value together with the in vitro observations above noted would suggest that gelatin reaches the duodenum with its gold number essentially unchanged.
This is a preliminary report
Get full access to this article
View all access options for this article.