In vitro gastric digestion of protein-based structured food : An engineering approach

To better design food, scientists need to better understand the underlying mechanisms of digestion. The aim of the thesis is to study the physicochemical processes in the gastric digestion of protein-based food matrices, to gain quantitative insight and mechanistic understanding of the gastric digestion of protein food. We first showed the importance of food structure, diffusion processes and enzyme kinetics in the gastric digestion, which defined the further exploration of this thesis. We determined the diffusivity of pepsin in water and in whey protein isolate (WPI) gels by fluorescence correlation spectroscopy (FCS). To further characterize the hindrance of the microstructure in the diffusive mobility of the enzyme, we used enhanced green fluorescent protein (EGFP) as the probe to study the diffusivity of proteins in varied protein gel matrices by FCS. We used isothermal titration calorimetry to study the enzymatic kinetics of pepsin with bovine serum albumin as the substrate. We found that pepsin has a higher activity at pH 2, while its affinity to the substrate is lower. At the same pH, pepsin has lower activity and affinity at higher ionic strengths. To quantitatively understand the gastric pH dynamics, we investigated the buffer capacity of proteins and the acid diffusion in protein gels, both theoretically and experimentally. By integrating the physicochemical processes involved in gastric digestion, we can better understand the disintegration and digestion kinetics of protein-based food matrices.

Bibliographic Details

Main Author:	Luo, Qi
Other Authors:	Boom, R.M.
Format:	Doctoral thesis biblioteca
Language:	English
Published:	Wageningen University
Subjects:	Life Science,
Online Access:	https://research.wur.nl/en/publications/in-vitro-gastric-digestion-of-protein-based-structured-food-an-en
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