Development of aqueous two-phase extraction systems for purification of anthocyanins and their characterisation

Anthocyanins are red, purple and blue colored components found in plants and are often used as coloring agents in the food, pharmaceutical and cosmetic industries in terms of their low toxicity. In this thesis project, it was aimed to show the extraction, purification, characterization and potential use of anthocyanins which can be used in food industry from various plant sources. As a source of anthocyanin; red cabbage, grape, strawberry, blackberry and cherry were used. Among these sources, red cabbage was found to have the highest anthocyanin content. In order to efficiently extract the red cabbage anthocyanins the extraction conditions were optimized. It was determined that the red cabbage homogenate prepared with water with the ratio of 1: 2 (w: v) heating for 15 minutes at 65 ° C and then stirring at 200 rpm for 1 hour at room temperature has highest anthocyanin content (97.9 mg / 100 g). An aqueous two-phase extraction (ATPE) system was developed for the economical and effective concentration and purification of red cabbage anthocyanins. The effect of extraction parameters such as ammonium sulphate and ethanol concentration, crude extract amount and pH was investigated. The anthocyanins were extracted with 22% (w / v) ammonium sulphate, 27% (v / v) ethanol, 2.5% (v / v) crude extract at pH 3 with the yield of 83.8%. Total flavonoid, polyphenol and sugar determinations were made in the upper and lower phases prepared with ATPE. In the upper phase of ATPE system, it was determined that 78.1% of flavonoids and 82.53% of polyphenolic compounds were concentrated in the upper phase whereas 79.5% of the sugars were concentrated in the lower phase. Under the optimized conditions, the stability tests of anthocyanins concentrated by ATPE system were carried out. Time dependent thermal stability and pH stability studies were performed. Red cabbage anthocyanins were found to be highly stable at a wide range of temperature (40-80 ° C) and pH (1-6).