Physical chemistry of gastric digestion of proteins gels

Abstract

In this paper, we present the rich physics and chemistry of the gastric digestion of protein gels. Knowledge of this matter is important for the development of sustainable protein foods that are based on novel proteins sources like plant proteins or insects. Their digestibility is an important question in the design of these new protein foods. As polyelectrolyte gels, they can undergo volume changes upon shifts in pH or ionic strengths, as protein gels experience when entering the gastric environment. We show that these volume changes can be modelled using the Flory-Rehner theory, combined with Gibbs-Donnan theory accounting for the distribution of electrolytes over gel and bath. In-vitro experiments of soy protein gels in simulated gastric fluid indeed show intricate swelling behaviour, at first the gels show swelling but at longer times they shrink again. Simulations performed with the Flory-Rehner/Gibbs-Donnan theory reproduce qualitatively similar behaviour. In the final part of the paper, we discuss how the model must be extended to model realistic conditions existing in the in-vivo gastric environment.

Pepsin activity as a function of pH and digestion time on caseins and egg white proteins under static in vitro conditions

“…The behaviour of food matrices in the acidic conditions of the stomach can impact the dynamics of gastric emptying, and hence the postprandial appearance of amino acids in the blood [1][2][3][4] . The gastric phase of digestion is, therefore, considered to be of paramount importance in the kinetics of digestion and absorption of dietary proteins [5][6][7] . At this stage, the enzymatic hydrolysis of proteins is initiated upon the action of pepsin, responsible for the hydrolysis of up to 5-15% of the peptide bonds 8,9 .…”

In silico trials of food digestion and absorption: how far are we?

“…A number of research groups continue to use and adapt models developed in the fields of engineering and biophysics to predict the behaviour of food in gastric conditions [7 ]. Recent examples include modelling work on mass transfer and absorption in the intestine [38], or on the physical-chemistry of gastric digestion of solid foods to predict: their swelling [39], their softening [40], their breakdown into particles [41], their acid and moisture uptake and buffering capacity [42][43][44]. Recently, a more integrative approach has also been proposed by Sicard et al to model of the gastric digestion of meat proteins [45 ].…”

Applying Hands-on Inquiry Learning in Physical Chemistry Teaching Practice to Improve Teaching Quality

“…Physical chemistry has become an important theoretical basis to support the development of medicines and pharmacies. 3,4 Traditional physical chemistry teaching is mostly based on classroom teaching, and experimental courses are mostly confirmatory or comprehensive experiments. For students majoring in pharmacy, it is difficult to achieve an in-depth understanding of the principle only by learning knowledge from the physical chemistry classroom.…”