Study on efficiency of betacyanin extraction from red beetroots

P>Red beetroots are rich in betalain pigments, which are divided into betacyanins (predominating in red beetroots) and betaxanthins. The objective of this work was to study efficiency of aqueous extraction of betacyanins from red beets. The experiment was conducted according to a central composite design, with the following variables: solvent pH (pH, 3.0-5.0), solvent-to-beetroot ratio (S/B, 1:1-5:1), solvent initial temperature (ST, 30-70 degrees C) and grinding time (GT, 2-10 min). Beetroots were ground with the solvent, filtered and evaluated for betacyanin contents. A highly significant model was obtained for betacyanin extraction efficiency (BEE), which was positively affected by ST and S/B, and inversely affected by pH. The most adequate extraction conditions were pH, 3.0; S/B, 5:1; ST, 70 degrees C and GT, 2 min. At such conditions, BEE was near 70%. The method is simple and produces a bright red-purple extract to be later dried or concentrated for use as a food colourant.