Adjusting the infogest digestion protocol for improved application of lipid digestion

Research output: Contribution to conferenceAbstract

Abstract

Background: Lipid digestion in humans results in more than 90 % lipid uptake in the small intestine. Most lipids are digested by the digestive enzymes to form free fatty acids (FFA) and monoacylglycerol (2-MAG). Whereas the majority of FFA and 2-MAG are absorbed by intestinal cells, a part might be used as substrate by the intestinal microbiota. To obtain more insights into dietary lipid intake, lipid digestion and potential effects on microbiota in the small intestine, relevant in vitro digestion models are needed. The INFOGEST digestion protocol is primarily optimized for protein digestion. However, lipid digestion has to deal with other variables than protein digestion, e.g. the lipase in the small intestine needs colipase as a cofactor for lipid digestion. In this study, the INFOGEST digestion protocol is optimized for lipid digestion and is made compatible with subsequent in vitro small intestinal fermentation experiments requiring a high FFA concentration. Since pancreatin contains a lot of material that can influence bacterial fermentations, pancreatin suspensions were processed to lower the residual, potentially interfering material.

Methods: The static INFOGEST digestion protocol for digestion of foods as described in Brodkorb et al was used as starting point. For optimisation of the protocol, different types of intestinal lipases were tested for lipase activity (3) and an ultrasonic treatment was included for dissolving pancreatic lipase. Colipase was extracted from pancreatin (2) for addition in the lipase activity measurements and lipid digestions. Lipid digestions were performed with varying amounts of sunflower oil and the addition of pancreatin or processed pancreatin with extra colipase. The % FFA at the end of the intestinal phase was calculated based on the NaOH consumption during titration together with the back titration of the digestion to pH 11,5 (4).

Results: Testing different types of intestinal lipases, we found that the lipase activity of porcine lipase extract decreased in time, whereas the activity of pancreatic lipase was stable. Ultrasonic treatment of pancreatic lipase lowered the residual material. However, we found that extra colipase was required to reach a similar lipase activity as non-processed pancreatin. Examining varying amounts of sunflower oil showed that digestion of 250 mg of sunflower oil results in 100% FFA compared to 63% FFA when 4 gram of sunflower oil was used. The concentration of FFA in the digest material was highest when 4 gram was used.

Conclusion: Processed pancreatin with lower residual material after ultrasonification, with addition of colipase can be used in lipid digestion and subsequent fermentations. Ratio of lipid versus lipase/colipase quantities matters (1). Despite the incomplete digestibility with 4g of lipid, the high concentration of FFA reached under these conditions is necessary for in vitro fermentations.
Original languageEnglish
Publication statusPublished - 9 Apr 2024
Event8th International Conference on Food Digestion - Porto, Portugal
Duration: 9 Apr 202411 Apr 2024

Conference

Conference8th International Conference on Food Digestion
Period9/04/2411/04/24

Keywords

  • Lipd digestion
  • INFOGEST

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