Low-sugar content betaxanthins extracts from yellow pitaya (Stenocereus pruinosus)

Consumer preferences, and potential health risks associated with the consumption of synthetic food colors, explain the commercial interest in alternatives from natural sources. Betaxanthins from cactus fruit have been used to color food products, but sugars are not usually removed from these extracts leading to processing and formulation challenges. In this study, low-sugar betaxanthin preparations were obtained from a crude yellow pitaya Stenocereus pruinosus extract using aqueous two-phase systems (ATPS). This study focuses on the effect of the salts and polymer choice (polyethylene glycol (MW 1000; PEG1000) or polyalkylene glycol copolymer (MW 3930, UCON), tie line length (TLL), phase volume ratio (V_r), and crude extract percentage on the partitioning of betaxanthins and sugars in the crude extract. PEG1000-phosphates were more suitable than UCON-salts for the extraction of betaxanthin. Multivariate analysis of variance (MANOVA, α = 0.05) showed that TLL, V_r and crude extract concentration effects were statistically significant (P < 0.05). The correlation with V_r, crude extract concentration, and TLL was determined by multiple linear regression. The desirability function was used to identify an ATPS (TLL = 37.7 %, Vr = 0.3, and 7 % crude extract) yielding a top phase with minimum total sugar (2.8 %) and maximum betaxanthin content (52.3 %).