engleski

Stability of selected biologically active compounds under simulated gastrointestinal conditions in relation to different food matrix

Due to a huge public interest in healthy and natural foods, containing biologically active compounds (i.g. polyphenols), functional foods represent a rapidly growing segment of the food industry. However, biologically active compounds that are the most abundant in the diet are not necessarily the most important, either because they are not stable under gastrointestinal conditions, poorly absorbed or rapidly eliminated. The food matrix plays a very important role in their stability. Its’ influence on gastrointestinal stability of biologically active compounds, as well as the different stability of pure compound compared with those incorporated in the food matrix is presented for several biologically active compounds (chlorogenic acid, rutin, rosmarinic acid, lycopene). Due to complexity of human digestive tract, inter-individual variations as well as the possibility to screen a number of samples in a relatively short time, a two-phase in vitro digestion model (gastric and intestinal) is used in order to investigate the stability of compounds. The concentration of selected compounds before and after simulated digestion process was detected using HPLC-DAD and spectrophotometric techniques. Obtained results generally show that the stability of selected biologically active compounds depends on specific gastrointestinal conditions (gastric and intestinal) as well as the matrix in which selected compound is incorporated. Chlorogenic acid showed a different stability in three matrices: after both phases of simulated digestion in a mixture of standard compounds it exhibited a nearly total loss (95.7%), in sea fennel matrix the loss of chlorogenic acid was 81.7% in comparison with caper matrix where its loss was only 33%. Similarly, the behavior of rutin towards the first (gastric) step varies from the 88 % loss in the standard mixture to the negligible 1.7% of the caper infusion. Rosmarinic acid also showed different stability in aqueous extracts from several aromatic plants belonging to Lamiaceae family (thyme, winter savory, marjoram and yarrow). The stability of pure rosmarinic acid is 30.7% after gastric phase in comparison with marjoram (14.1%) or thyme (0.8%). After intestinal phase the stability of pure rosmarinic acid was 78.6%, while the same compound was completely degraded in plant extracts. Lycopene extract showed the highest stability after gastric and intestinal phase in red pepper in comparison with its stability in carrot and tomato. The selection of optimal food matrix for studied biologically active compound will ensure its stability and prolonged biological activity under simulated gastrointestinal conditions. Such results are helpful for creation and optimization of the healthy diet model as well as for development of new functional foods enriched with food extracts containing stable and biologically active compounds.

polyphenols; food matrix; in vitro digestion; human digestive enzymes

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