Simultaneous stabilization of blueberry anthocyanin colorant through microencapsulation and ferulic acid...

Anthocyanin extracts from blueberry skin have good potential to develop red-bluish food colorants with functional properties, such as antioxidant activity, but limited stability. The objective of this work was to evaluate the combination of copigmentation (non-covalent associations of anthocyanins with colorless molecules) and microencapsulation by spray drying as an effective strategy for the synergistic stabilization of anthocyanin pigments. For this purpose, copigmentation was evaluated by the presence or absence of the copigment ferulic acid in spray dried powders (pigment/copigment ratio 1:3). Maltodextrin was used as encapsulating agent at 2.5 % in feed solution and different maltodextrin/blueberry pigment ratios were studied (MD/BP 500:1, 400:1, and 300:1). Copigmented and non-copigmented blueberry colorant powders were assessed for their physico-chemical, bioactive, and coloring properties, and their storage and thermal stability. The lower MD/BP ratio (300,1) resulted in the highest powder yield (82 %) promoting higher anthocyanin content and retention (TMA = 2.61 mg/g powder; 43 %), total phenolic compounds (3.7 mg/g powder), and antioxidant capacity (3.71 mM TE/100 g powder) while the presence of ferulic acid at all the MD/BP ratios improved these properties in microparticles. The lower MD/BP ratio led to higher coloring and bioactive power when microparticles were dissolved in aqueous solution, and the respective ones copigmented with ferulic acid favored perceptible bluish tonalities at MD/BP 300:1 (ΔE^⁎_ab = 7.4 respect to non-copigmented ones). During storage, the presence of ferulic acid extended in all cases the anthocyanin shelf-life in blueberry microparticles summited to long-term oxidative degradation (40 °C). The application of copigmented and non-copigmented blueberry powders in a model sport drink confirmed the protective effect of ferulic acid against the anthocyanin and color degradation during pasteurization processes. Thus, the combination of both strategies is useful to modulate the properties of blueberry anthocyanin colorants and to improve its stability.