Effect of extrusion on bioactive compounds found in artichoke leaf powder and on their in vitro bioaccessibilities

Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Food Engineering, Turkey

Approval Date: 2016

Thesis Language: English


Principal Supervisor (For Co-Supervisor Theses): İlkay Şensoy

Co-Supervisor: Hamide Şenyuva


The functional properties of extruded products can be enhanced by addition of herbal ingredients. In this study, artichoke leaf powder (ALP) was added to extrudates, at 3%, 6% and 9% concentrations, to increase amount of bioactive nutrients. Aim of the study was to investigate the effect of extrusion on functional components and in vitro bioaccessibility of selected phenolic compounds. Extrusion feed flow rate was 55 ± 1 g/min, screw speed was 250 rpm and barrel temperature zones were set at 80°C, 90°C, 130°C and 150°C (die: 128°C). Total phenolic content and antioxidant activities were measured. LC-MS/MS was used for quantification of selected phenolic compounds. Total phenolic content of extrudates and raw mixtures increased with increasing ALP concentration. Extrusion process caused a significant decrease in total phenolic content for all ALP concentrations. Similarly, antioxidant activities of samples increased with increasing ALP concentration. Antioxidant activities of 3% and 6% ALP added samples did not change after extrusion. Antioxidant activity of 9% ALP added samples decreased after extrusion process. Extrusion process adversely affected cynarin and cynaroside contents of samples. However, in vitro bioaccessibilities of cynarin and cynaroside compounds increased after extrusion process.