Changes of antioxidant potential of pasta fortified with parsley (Petroselinum Crispum mill.) leaves in the light of protein-phenolics interactions.

BACKGROUND Pasta is considered as an effective carrier of prohealth ingredients in food fortification. The aim of this study was to examine the changes of antioxidant potential of wheat pasta affected by fortification with powdered parsley leaves. A special attention was paid to effectiveness of fortification in the light of proteinphenolic interactions. METHODS To improve antioxidant activity of pasta, part of wheat flour was replaced with powdered parsley leaves from 1% to 4% (w/w). The total phenolics content was determined with Folin-Ciocalteau reagent. Antioxidant capacity was evaluated using in vitro assays - abilities to scavenge free radicals (ABTS) and to reduce iron (III) (FRAP). Predicted phenolic contents and antioxidant activity were calculated. To determine the protein-phenolics interactions SE-HPLC and SDS-PAGE techniques were used. RESULTS Fortification of pasta had a positive effect on its phenolic contents and antioxidant properties. The highest phenolics level and antioxidant activity of pasta were obtained by supplementation with 4% of parsley leaves. However, in most cases experimental values were significantly lower than those predicted. The protein profiles obtained after SDS-PAGE differed significantly among control and enriched pasta. Furthermore, the addition of parsley leaves to pasta resulted in increase of peaks areas obtained by SE-HPLC. Results indicate the occurrence of the protein-phenolics interactions in fortified pasta. CONCLUSIONS Overall, the effectiveness of fortification and consequently biological effect is limited by many factors including interactions between phenolics and pasta proteins. In the light of this results the study of potential interaction of bioactive supplements with food matrix should be taken into account during designing new functional food products.