In vitro digestion of lactoferrin-glycomacropeptide nanohydrogels incorporating bioactive compounds: Effect of a chitosan coating

Abstract

The behaviour of lactoferrin (Lf) glycomacropeptide (GMP) nanohydrogels with and without a chitosan coating was evaluated during gastrointestinal digestion. The application of a chitosan coating allowed to reduce the protein degradation from 86% to 76% for Lf and from 71% to 53% for GMP. Protein bioaccessibility results showed that in nanohydrogels with chitosan coating 23% of Lf and 40% of GMP remained intact until absorption. Based on these results, the bioaccessibility of two different bioactive compounds encapsulated in Lf-GMP nanohydrogels with chitosan coating was evaluated during gastrointestinal digestion. Curcumin was used as lipophilic model compound and caffeine as a hydrophilic model compound. Bioaccessibility of curcumin in coated nanohydrogels was 72% while the corresponding value for curcumin in free form only reached 66%. It was also observed that under simulated gastric and intestinal conditions, free curcumin lost around 68% of its antioxidant activity while when incorporated into nanohydrogels only 30% of this activity was lost. Results also showed that the bioaccessibility of caffeine encapsulated in coated nanohydrogels was 63% while caffeine in free form only reached 59%.