Color Photostability Assessment of Ultrasound-Assisted Extracts From European Blueberry (Vaccinium Myrtillus L.) Obtained with The Use of Non-Toxic Solvents

In recent years, the search for environmentally friendly industrial solutions has been gaining momentum, especially in the areas of materials science and food technology. The aim of this study was to evaluate the color photostability of European blueberry (Vaccinium myrtillus L.) extracts obtained with the use of non-toxic solvents. Extracts of lyophilized forest berries were prepared with the use of water, ethanol, glycerin, and their mixtures by means of ultrasound-assisted extraction. ATR-FTIR spectroscopy was used to determine chemical structure. Color measurement in the CIELab color space was performed before, during and after the QUV accelerated weathering test conducted for dyed cotton substrates. The content of anthocyanins expressed as cyanidin 3-glucoside equivalents was determined based on UV-Vis absorbance intensity measurement and a pH-differential method. The highest color photostability was observed for the extract prepared using water and ethanol in the proportion 50/50 (v/v). However, the highest content of anthocyanins was recorded for the mixture of glycerin and ethanol in a ratio of 50/50 (v/v). It is shown that the addition of glycerin supports the extraction of anthocyanins to some extent; however, it results in a reduction of the color photostability of extracts used to dye cotton fabrics.