Buffering capacity (BC) is an important physicochemical property of foods that expresses the food’s resistance to a change in pH with the addition of an acid or base, thus directly influencing the regulation of gastric enzymes, the solubility of dietary ingredients, the gastric breakdown of food nutrients, and, consequently, their absorption through the regulation of gastric pH.
The purpose of a recent Austrian study (2023) was to analyze the buffering capacity and amount of HCl required to acidify a food as an indication of both the acidity and gastric digestion of commercial and homemade dog foods in relation to their nutritional composition.
The study developed prediction equations to estimate buffer capacity using a series of 30 complete dog foods, ten different types of dry and wet commercial dog food, and homemade dog food.
To analyze a possible effect of food on gastric pH, the buffering capacity was quantified by an acid titration method. The different foods were ground and, in short order, aliquots of 0.5-2 ml of 0.16 M HCl were added to the sample until an end point of pH 2 was reached.
The results
The buffering capacity of wet, dry and homemade dog foods was quantified by an acid titration method until a pH below 2 was reached.
Wet food had the highest buffering capacity; between dry and homemade food there were no significant differences. Using multiple regression analysis, it was possible to establish associations between nutrient composition and dog food BC. The excessively high ash content found in moist foods could be a risk factor for gastric dilatation and volvulus syndrome because it could lead to excessive lowering of pH in the stomach.
The crude protein concentration of the food was the most important factor influencing the buffering capacity and HCl use, while the initial pH had only a weak significant influence.
The buffering capacity can be estimated based on the protein and ash content of the food, using the equations developed in this study: a high protein and ash content indicates a high buffering capacity of the food.
The results indicate large differences in the buffering capacity of typical dog foods; therefore, estimating the buffering capacity could help design customized dog diets, particularly for dogs with health problems such as gastric hypoacidity, acid reflux or gastritis.
Reference
Stefani, V.; Lucke, A.; Zebeli, Q. Buffering Capacity of Various Commercial and Homemade Foods in the Context of Gastric Canine Digestion. Animals 2023, 13, 3662 . https://doi.org/10.3390/ani1323366.
