Liofilizado para o preparo de bebida probiótica a base de umbu-cajá e acerola

Abstract

The objective of this research was to define the drying condition that provides a better performance in the retention of phenolic compounds, ascorbic acid and probiotic microorganisms contained in the lyophilisate for the preparation of a probiotic drink based on umbu-cajá and acerola. For this, kefir was reactivated by backslopping and inoculated in proportions (25% and 50%) in the isolated pulps of acerola and umbu-cajá. The 25% kefir to 75% mixed drink dilution rate, defined as ideal, was used in formulations to define the best probiotic beverage formulation (9 trials), and evaluated for bioactive retention (polyphenols and ascorbic acid) and viable probiotic cells. The formulation with 90% of umbu-cajá and 10% of acerola, for having obtained satisfactory performance in the fermentation, was submitted to an experimental design 2³ (17 tests) to define the drying conditions, having as independent variables the drying air temperature (-30 °, -34 °, -40 °, -46 ° and -50 ° C), percentage of sucrose (5, 7, 10, 13 and 15) and percentage of maltodextrin 10DE (10,12,15,18 and 20). The process using a temperature of -40 ° C, 10% sucrose and 15% maltodextrin produced the best responses and was characterized with hygroscopicity of 13.13g.100g -1, apparent density of 0.52g.mL -1 , yield of 39.21% and solubility of 37.07%. Liquid and liquid lyophilized extracts were obtained from liquid-liquid extraction for determination of total polyphenols, total tannins, antioxidant capacity (inhibition of DPPH *) and phenolic profiles of fruit pulps (umbu-cajá and acerola) and mixed beverages, probiotic and lyophilized and organic acids. Specific extraction methods were used to quantify carotenoids, anthocyanins and total flavonols. The pulp of umbu-cajá presented high concentration of carotenoids and that of acerola expressive contents of total polyphenols. Among the fermentation and lyophilization stages, polyphenols, flavonols, total tannins, and antioxidant capacity showed a significant increase. Similar behavior was observed for malic acid and inverse for ascorbic acid. By means of the phenolic profile it was possible to quantify rutin, mesylic and vanillic acids and trans-reveratrol in the acerola pulp, with only flavonol and phenolic acids remaining in the freeze-dried product. Positive correlations were identified between the free radical sequestration capacity and total flavonols, tannins and polyphenols. Principal components analysis extracted 100.00% of the total variance and characterized lyophilized by malic acid, polyphenols, flavonols and total tannins, and percent inhibition of DPPH *. All data were obtained in triplicate and submitted to Student's t-test, DUCAN and ANOVA, analysis of variance and test of means, as well as multivariate and correlation analyzes. The results highlight the importance of the research for the strengthening of the fruit production chain, mainly in the Brazilian northeast, where the culture of the umbu-cajazeiro and the cherry tree has provoked economic interests.