TLC with densitometric and image analysis in the control of anthocyanin content in fruits of Rubus occidentalis and Rubus idaeus cultivars and hybrids

A TLC method was developed for the determination of anthocyanins in the fruits of some cultivated varieties of Rubus occidentalis (black raspberries) and Rubus idaeus (red raspberries) and their hybrids. Anthocyanin sets in fruits’ extracts were determined on TLC silica gel 60 F₂₅₄ plates using mobile phase consisted of ethyl acetate-water-formic-acid (100:30:30, V/V), at 4°C (±1°C), at a distance of 70 mm with the use of densitometry and videoscanning. The obtained results were comparable to the results of quantitative analysis performed using by the HPLC-UV/VIS method performed on a Kinetex C-18 column using gradient elution comprising an increase concentration of acetonitrile-water-trifluoroacetic acid (50:50:0.1, V/V) in water-trifluoroacetic acid (99.9:0.1, V/V) from 12 % to 40 % within 40 minutes at 520 nm. The TLC method with videoscanning provides immediate capture of data for unstable compounds like anthocyanins before their partial degradation.