Abstract
The high antioxidant capacity of plant polyphenols has received attention from the food, cosmetic and pharmaceutical industries. The extraction and characterization methods applied for polyphenols are of high importance for their valorization. The extracted polyphenols can be used as food additives to increase stability and quality. Recently, the efficiency of phenol extraction processes has been greatly improved by implementing both physical methods (ultrasounds, or microwave assisted extraction etc.) and chemical hydrolysis (with acidic, and alkaline solutions etc.). Advanced analytical techniques, such as high-performance liquid chromatography (HPLC) coupled with various detectors, have become a common practice to fully identify and quantify the polyphenols from food materials. This PhD thesis research aimed to increase the efficiency of polyphenol extraction from both physical and chemical perspectives by using cascade extraction and alkaline hydrolysis. A triple detector system, consisting of a diode array detector (DAD), mass spectrometry (MS) and coulometric array detector (CoulArray), coupled to HPLC has been developed to screen and characterize polyphenols from plants rapidly and with high precision. The final goal is to achieve a better understanding of phenol extraction methods from food materials and herbs and develop a fast and reliable detecting system for phenol analysis.