In Vitro Digestion of High-Fat Commercial Dairy Products: Detailed Analysis of Lipid Classes

This study aimed to comprehensively analyze lipid classes after in vitro digestion of high-fat commercial dairy products. The research focused on the fatty acid (FA) profiles of triacylglycerols, diacylglycerols, monoacylglycerols (MAG), free FA (FFA), and polar lipids of digested full-fat cream, full-fat sour cream, cream cheese, and a Gouda-type cheese. We employed the INFOGEST 2.0 digestion model. The isolated lipids were fractionated by solid-phase extraction, and the FA profile of each fraction was analyzed using GC–MS. The digested dairy products revealed similar results for the relative amounts of the analyzed lipid classes. However, the cream digest had a significantly lower amount of MAG than the other products. Furthermore, the proportion of individual FAs and FA groups in the lipid classes was found to vary significantly between the digested dairy products. The replicates of cream cheese and sour cream showed a homogenous lipid digestion, whereas the lipid classes after digestion of cream and the Gouda-type cheese were more diverse. This could be due to differences in product pH and protein and calcium content.

Practical Applications: The findings of our study indicate the importance of considering lipid classes other than FFA, as well as the FA composition of these, when studying the lipid digestion of different dairy products. This is especially true for MAG, which is absorbed in the intestine along with FFA. The observed differences in the lipid profile of the digested dairy matrices explored in our study demonstrate that product pH, homogenization, texture, and calcium and protein content could impact lipid bioaccessibility, which could potentially have physiological implications. These factors should, therefore, be assessed in relation to lipid digestion.