Reactivity of peptides within the food matrix.

Numerous biological activities have been reported for peptides or peptide-rich fractions from hydrolyzed food proteins. Some of the properties of peptides include antioxidant, antimicrobial, anti-inflammation, antihypertensive, and immune system modulation. To evaluate the efficacy of peptides in vivo, foods have been used as carrier vehicles. However, there are many molecules in foods that can react or interact with peptides, thereby reducing the bioavailability or bioactivity of these peptides. The Schiff base reactions of peptides with reducing sugars are well established. Peptides can also react with oxidized lipids or reactive oxygen species. Secondary metabolites such as quinones in foods, can react as well with amine or thiol groups of peptides. All these reactions affect the concentration of peptides. This review summarizes and discusses some of the implication of those reactions on the availability of bioactive peptides within the food matrix. PRACTICAL APPLICATIONS: Bioactive peptides possess specific effects on foods like preventing oxidative rancidity. In human, they may lower blood pressure or reduce inflammation. The knowledge on the type of reactions these peptides may encountered when foods are used as transport vehicles is essential. This will prevent variability in intake and ensure proper dosage and reproducible results.