Coloring foods from yellow-orange cactus pear
The aim of this study was to obtain coloring foods from yellow-orange cactus pear pulp by vacuum concentration and freeze drying. Concentrated coloring food (VC) was obtained in a Büchi evaporator (30°C, 17 mbar) up to 45±1 °Brix and freeze-dried (FD) powders in a Shin BioBase FD5508 equipment, using maltodextrin as carrier in 1:1 ratio (pulp soluble solids/maltodextrin). The products were characterized and their stability tested in storage (23±2°C) for 30 days. Color parameters (L, a*, b*, C* and h°) were measured in a Hunter Lab Ultra Scan Pro and total color change (ΔE) was calculated. Betaxanthins were determined by HPLC. Betaxanthins and color degradation of both food colorants were evaluated in a soft-drinks model during storage at 4±1°C. Betaxanthin contents were 256.53±4.81 and 263.76±5.21 mg indicaxanthin equivalents (IE) kg‑1 in VC and FD, respectively. When VC and FD were compared with the fresh pulp, a visible color change was observed in both cases, of 39.2 and 43.1, respectively. In the VC, the decrease in betaxanthins was not significant during storage, but a perceptible color change (ΔE=15.0) was detected. However, betaxanthin content and color parameters showed no significant changes in FD colorant during storage (ΔE=5.6). Nevertheless, both food colorings showed good stability at room temperature. Regarding performance as colorants in the soft-drinks model, betaxanthin degradation was significant when both colorants were applied. Degradation rate constants for soft-drinks models (SVC and SFD) were k = 1.57×10‑1±8.0×10‑3 and 2.0×10‑1±6.0×10‑3 day‑1, respectively, which were significantly different. Total color changes of 10.7 (soft drink with VC) and 15.7 (soft drink with FD) were reached at the end of storage. The results showed that FD could be used for coloring instant food (soup or soft-drink powders). VC shows potential for coloring food stored at low temperatures, e.g., chilled matrices such as yogurt or ice creams.
Carmona, J.C., Fabry, A.M. and Sáenz, C. (2019). Coloring foods from yellow-orange cactus pear. Acta Hortic. 1247, 15-22
Opuntia ficus-indica, betaxanthins, concentrate colorant, freeze-dried, soft-drink model