Micropartículas de betalaínas extraídas da casca de frutos de pitaia (Hylocereus polyrhizus) aplicadas em extrato hidrossolúvel de soja.

Abstract

Color is an important parameter in food products acceptance by consumers. There is a demand for vegetable-originated natural dyes due to the impacts which artificial dyes may have on both nature and human health and even for religious or ideological reasons preventing specific groups or tribes from consuming animal-originated natural dyes. Therefore, betalains extracted from pitaia bark become an effective choice for dyes production. Because such a substance is unstable its association with protective materials tends to be an interesting alternative. This work was carried out with the objective of producing, characterizing and applying betalain microparticles. The pitaya peels were obtained from fruits that would be discarded at first. After cleaning, hydroalcoholic extraction was performed to obtain a betalain-rich extract. Different formulations (EPL, M10, M30, M+G and M+P) containing the betaláin- rich extract which had been previously characterized with different drying (maltodextrin, soy protein and xanthan gum) were produced. The apparent viscosity of the solution was performed. After drying by freeze-drying, betalain microparticles were obtained which were characterized for their moisture, water activity, solubility, degree of caking, wettability, bulk density, yield, retention, betalain content, and color. In addition, FTIR, TGA, and morphological analysis tests were performed . After that the microparticles were applied to a soy drink to give it color. It was found that the microparticles obtained from drying materials had better reconstitution and morphological characteristics although the control formulation (EPL) has shown a higher betalain content. The formulation containing 30% maltodextrin showed better results, with regard to reconstitution characteristics, thermal analysis, and morphological structure, therefore, it was submitted to the stability test. Refrigeration and especially freezing were effective in reducing the loss of betalains from the drink. We concluded that the use of betalain dye produced from pitaya peel, containing 30% of maltodextrin as a drying aid is a good option as a dye in soy beverages. As to stability, storage under refrigeration or freezing was found to be a strategy of interest to preserve such pigments.