Validation of aqueous two-phase extraction method

Abstract

Nowadays, consumer interest in food with natural ingredients has increased. This need has led to the research of new sources and green extraction methods. Betalains are compounds responsible for giving color to cacti fruits. The aim is to obtain low-sugar betacyanins extracts from jiotilla Escontria chiotilla using aqueous two-phase systems (ATPS) to color food with the extract. The effect of principal parameters of ATPS (Ethyl alcohol- KH₂PO₄/K₂HPO₄) as tie-line length (TL;40,50 and 70), phase volume ratios (Vr; 1 and 3) on the partitioning of betacyanins, betaxanthins, total sugars, reducing sugars, and antioxidant activity in the extract was evaluated. The yields were determined from the top and bottom phases of the aforementioned parameters. Multivariate analysis of variance (MANOVA, α = 0.05) showed that TLL and Vr were statistically significant (P < 0.05). The lowest bottom sugar yield (25.78 ± 3.14%) corresponds to TLL = 40, Vr = 3. Under these conditions, the corresponding value for betacyanins yield is 62.98±4.52%. For the first time, the ATPS was used to extract betacyanins from cactus fruit.•Escontria chiotilla, as a biological source, contained a high percent of betalains•Aqueous two-phase systems (ATPS) was statistically optimized•The developed method enriches the valorization of environmentally related plants waste materials.

Keywords: Aqueous two-phase systems; Betacyanins; Betalains; High-value compounds.

Graphical abstract

Fig. 1

Scheme based on aqueous two-phase system extraction of betacyanins.

Fig. 2

Estimated marginal means of yields (statistical test) in top and bottom phases are represented as follows: betacyanin yield $\left(Bc{Y}_t\right)$ with sky blue and circle, betaxanthin yield$\left(Bx{Y}_t\right)$ with blue and squares, total sugars yield$(S{Y}_t$) with orange color and diamond, reducing sugars $\left(Rs{Y}_t\right)$ yellow and triangles. TLL means tie line length, Yt means yields in top phase, Yb means yields in bottom phase, Vr 1 means volume ratio 1, Vr 3 volume ratio 3. In subsection A, Vr 1 is found in the top phase. In subsection B, Vr 3 is found in the top phase. In subsection C, Vr 1 is found in the bottom phase. In subsection D, Vr 3 is found in the bottom phase.