Development and characterization of standardized model, solid foods with varying breakdown rates during gastric digestion

Standardized, model solid foods were developed with varying initial hardness and breakdown rates during in vitro digestion. One class of model foods was based on the Standard American Diet, with strong and weak gel versions created by modulating pH. Another class was developed using whey protein hydrogels, with strong and weak gel versions produced by addition of pectin. The initial hardness of the model foods ranged from 6.2 +/- 1.0 N (whey protein weak gel) to 56.2 +/- 5.7 N (whey protein strong gel; p < 0.05), and softening half-times ranged between 58 +/- 5 min (standard diet weak gel) and 775 +/- 82 min (whey protein strong gel; p < 0.05). The model foods were placed into distinct classes according to the Food Breakdown Classification System. These model foods could help future studies develop relationships between food physical property changes during digestion and variables such as gastric emptying and satiety.