Monitoring protein hydrolysis by pepsin using pH-stat: In vitro gastric digestions in static and dynamic pH conditions

Damien Mat (1, 2, 3) , Thomas Cattenoz (1) , Isabelle Souchon (1) , Camille Michon (2, 3) , Steven Le Feunteun (1)

1 GMPA - Génie et Microbiologie des Procédés Alimentaires
2 GENIAL - Ingénierie, Procédés, Aliments
3 Université Paris-Saclay

This study intends to demonstrate that acid titration at low pH is very well adapted to the monitoring of pepsin activity. After a description of the underlying principles, this approach was used during in vitro gastric digestions of a model of complex food containing 15 wt% of whey proteins, according to both static (2 h at pH = 3, Infogest protocol) and dynamic pH conditions (from pH 6.3 down to 2 in 1 h). Pepsin activity was quantitatively assessed in all experiments through the calculation of degrees of hydrolysis (DH). Final values of 3.7 and 3.0% were obtained in static and dynamic pH conditions, respectively, and validated using an independent method. Results also show that about 92% of the peptides were detected at pH = 3, and 100% for pH 2.5. Overall, the proposed approach proved to be very worthy to study protein hydrolysis during in vitro gastric digestions.

Mots clés: In vitro digestion; Whey proteins; pH-stat; Titrimetry; Pepsin; Aspartic proteases; Proteolysis; Hydrolysis

Domaines: Sciences du Vivant [q-bio]

Damien Mat, Thomas Cattenoz, Isabelle Souchon, Camille Michon, Steven Le Feunteun. Monitoring protein hydrolysis by pepsin using pH-stat: In vitro gastric digestions in static and dynamic pH conditions. Food Chemistry, 2018, 239, pp.268-275. ⟨10.1016/j.foodchem.2017.06.115⟩. ⟨hal-01621904⟩