Elaboração de bebida probiótica a partir de suco de mirtilo (Vaccinium myrtillus) fermentado com Lactobacillus casei

Abstract

With the growing concern about the quality of life and health of consumers, the food and beverage industry has played a fundamental role in meeting the needs of changing consumption of the population. For this reason, the só-called “functional” food market has grown in recent times proving the benefits of its intake. Blueberry (Vaccinium mirtyllus) is known to be a fruit rich in phenolic compounds and antioxidants, acting in a functional way in the human organism, being able to be consumed of diverse forms, as in juices, jellies, dehydrated, sauces, among others. It is a characteristic plant of cold climates and found mainly in the USA and Europe, however, there are reports of cultivation in the South of Brazil. In order to meet the market demand, from a nutritional and biological point of view, for healthier and more functional foods, the aim of this work was to elaborate a probiotic juice based on blueberries with different sugars, refined sugar, (F1), honey, (F2), fructose, (F3) and (without addition of sugars) control (C), added at the concentration of 5% (w/w) in 500 mL of juice, fermented by the microorganism Lactobacillus casei for 48 hours at 37 °C. For the control of the fermentation process, pH and ºBrix measurements were carried out during fermentation every 4 hours, until 48 hours of the process. The cell viability was determined at the end of the fermentation and, the cell growth and the biomass production during the fermentation process, by reading the optical density (D.O) at 590 nm, in addition to the sensorial acceptance (ADQ) and affectivity tests. With the elaborated drink, it was possible to verify that all the formulations presented acidic pH, being the lowest pH found for the formulation (F1), 3.56 ± 0.07, and the highest, for formulation (C), 4.64 ± 0.04. During the fermentation process, all formulations showed a reduction of ºBrix, with the highest consumption (42.5%), for formulation (C) and lowest (18.75%) for formulation (F3). The formulations (F1) and (F3) presented cellular viability of 3.0×107 UFC·mL-1 and 9.0×107 UFC·mL-1, respectively, higher than the values recommended by the legislation (≥ 106 UFC·mL- 1). The highest biomass production (0.54 ± 0.08 g·L-1) was identified for the formulation (F2) and the lowest (0.41 ± 0.04 g·L-1) for formulation (C). The formulations used for the ADQ and affectivity tests were performed for the samples that presented cell viability greater than 106 UFC·mL-1 and showed that the formulation (F1) had a better overall impression (6.5 ± 0.17) and higher purchase intention (3.5 ± 0.13), presenting significant differences (p ≤ 0.05) in relation to formulations (C) and (F3), indicating that the addition of refined sugar significantly improves the sensorial aspects of the product, being classified in the intermediate zone of sensorial acceptance with values between 5 and 7.8 in the hedonic scale