Physical and Chemical Property Changes during In-vitro Gastric Digestion of Boiled and Fried White Potatoes

Student Name: 
Daniel Kim
UCD Department: 
Department of Biological and Agricultural Engineering
UCD Mentor: 
Gail Bornhorst

As the physical properties of foods are linked to the processes and the functionalities of the digested materials, a demand for the knowledge of how food behaves during gastric digestion from the public has increased. The main objective of this study was to compare two contrasting cooking methods, frying and boiling, that were utilized in order to investigate the differences between the physical property of the boiled and fried white potatoes. The data collected will be part of a broader system that classifies food based on digestive properties: The Food Breakdown Classification System. This classification system aims to predict a food’s digestive behaviour based on its physical properties measured after in vitro digestion. The physical property that was measured from the white potatoes in this experiment was hardness. A Texture Analyzer was used to measure the hardness. The pH and the brix of the digestive fluids were also accounted for. Potato cubes were digested in simulated saliva and gastric juice for six time points of varying length. It was hypothesized that the potato cubes digested for longer time points were to have lower hardness values overall. Also, the pH and the brix of the digestive fluids were expected to increase as the digestion time increased. At the end of the investigation, it was concluded that the fried potatoes had an overall lower hardness than the boiled potatoes. LIkewise, the pH and the brix of the digestive fluids of both boiled and fried white potatoes increased as the digestion time increased.