Enzymatic and chemical conversions taking place during in vitro gastric lipid digestion: The effect of emulsion droplet size behavior

• Published in: Food chemistry 2020-10, Vol.326, p.126895-126895, Article 126895
• Main Authors: Infantes-Garcia, M.R., Verkempinck, S.H.E., Guevara-Zambrano, J.M., Andreoletti, C., Hendrickx, M.E., Grauwet, T.
• Format: Article
• Language: English
• Subjects: Droplet size; Emulsion; Gastric lipase; Gastric lipid digestion; In vitro; Molecular mechanisms
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2020.126895

•Emulsion droplet size affected the overall gastric lipolysis kinetic parameters.•Stability of emulsions during digestion impacted kinetics of gastric lipolysis.•Multiple lipid digestion products of interrelated reactions were quantified.•Multi-response modeling allowed the elucidation of lipolysis molecular mechanisms.•Multi-response modeling allowed the interpretation of lipolysis kinetic parameters. This investigation reports the effect of droplet size behavior on the overall lipolysis profile and molecular lipolysis mechanisms under in vitro gastric conditions. O/W emulsions (5% triolein, 1% sodium taurodeoxycholate) with different initial droplet sizes (fine: 0.58 μm; medium: 1.82 μm; and large: 4.00 μm) were subjected to static in vitro digestion. For the first time, multiple lipolysis products including diolein and monoolein regioisomers were quantified within a single HPLC run. An inverse relation was found between the droplet size and the initial rate and final extent of lipolysis based on the digested triolein. Furthermore, a mechanistic gastric lipolysis model was established based on a reaction scheme including enzymatic and chemical isomerization conversions. The estimated rate of the sn-1/3 hydrolysis was around two- to thirty-fold faster compared to the rates of sn-2 cleavage and isomerization, respectively. These findings resulted in a profound insight in in vitro gastric molecular lipolysis mechanisms.