Desenvolvimento de polpa de mirtilo (Vaccinium ashei Reade) e preservação das suas antocianinas para aplicação em alimentos.

Abstract

The blueberry is a fruit whose cultivation is expanding in Brazil, mainly because it has a high content of anthocyanins, pigments with high antioxidant activity that giving characteristic color to the fruit, but which are unstable against the processing and storage. In this work was evaluated, as soon after production and at 30, 60 and 90 days, physico-chemical characteristics and the protective effect of xanthan on anthocyanins in four different blueberry pulps produced with and without prior disintegration of the fruit. With the best formulation obtained was elaborated five alternative formulations of mousses, without the addition of products of animal origin, made with soybean cream, xanthan and guar, in different proportions. The mousses was evaluated in the first and fifth day after processing. The pulps did not differ significantly with respect to the values of ash and total soluble solids, but for humidity. The pH decreased concurrently with the increase in acidity between the initial time and 30 days when it was found equalization between the components of the formulations. The use of xanthan gum and the prior disintegration favored this effect. The prior disintegration increased the anthocyanins degradation during pulp processing. The xanthan addition increased, apparently, the initial liberation of anthocyanins. However, in 90 days of storage the higher retention of anthocyanins in relation to initial time has occurred in the formulations without xanthan gum with disintegrated fruit (62.45%) or whole fruit (45.71%), indicating that the initial rapid anthocyanins liberation was followed to a rapid degradation. Was verified important antioxidant activity in the pulps (3.045 to 2.342 mMol TE. g-1), with high preservation of this during storage. We identified four anthocyanins/anthocyanidins, pelargonidin, kuromanin, keracyanin and malvidin, whose proportions were similar in all four formulations. The chromaticity coordinates indicate tendency of pulps to red color, with traces of blue. During storage, had reduction of luminosity (L*), a* and chroma and increased of b*. The pulps elaborated with disintegrated fruit had higher values of ΔE, and the xanthan addition with prior disintegration resulted in better results for color. In mousse, made with the pulp 4, no significant difference between the colors, except for the lowest L* for formulation A, with a smaller total percentage of gum, 0.8%. By rheological analysis was found in the formulations a pseudoplastic behavior and gel consistency true with a small reduction in viscosity and gel strength of the first to fifth days after processing. By sensory evaluation, was verified a higher preference of the judges for formulation A (0,4% xanthan gum and 0,4% of guar), less viscous both one day and five days after processing. Furthermore, 70% of judges said that they probably or certainly buy the formulation A, thereby demonstrating a potential for possible inclusion in the market, taking into consideration the realization of the analysis with judges outside the specific market niche.