Elaboração de kombucha saborizada com gengibre amargo (Zingiber zerumbet) e camu-camu (Myrciaria dubia) a fim de agregar valor funcional

Abstract

The growing concern with health and well-being is leading the community to seek healthier options, such as functional beverages, which offer additional nutrients, supplement the diet, and contribute to the proper functioning of the consumers' organisms. The present study aimed to elaborate kombucha flavored with bitter ginger (Zingiber zerumbet Smith) and camu-camu (Myrciaria dubia) in order to obtain a functional beverage. Analyses were performed to quantify the contents of moisture, ash, lipids, proteins, fiber, carbohydrates, and caloric value in in natura camu-camu fruits, commercial camu-camu pulp, and powdered camu-camu, as well as in bitter ginger rhizomes. The pH, density, and titratable acidity were monitored throughout the first fermentation of the original kombucha. Six kombucha formulations were prepared, including the original and those flavored with camu-camu (20%), powdered camu- camu (10%), and bitter ginger extract (0.1%). These formulations were submitted to a second fermentation, and subsequently, physicochemical analyses of pH, density, volatile acidity, and alcoholic content were performed. To quantify bioactive compounds in the formulations, analyses of antioxidant activity (DPPH and ABTS), total phenolic compounds, and flavonoids were executed. Finally, microbiological analyses of yeasts, lactic acid bacteria, total bacteria, and total and thermotolerant coliforms were conducted.The results found indicated that powdered camu-camu is an excellent raw material for kombucha, as it presented proteins (1.33%), fiber (1.55%), and carbohydrates (92.59%). In natura camu-camu also proved to be a great option, with proteins (0.76%), fiber (0.93%), and carbohydrates (8.53%). The dried bitter ginger presented results of proteins (7.19%), lipids (3.82%), fiber (11.16%), and carbohydrates (7.73%). In the first fermentation, there was a good evolution of the fermentation process, showing a gradual reduction in pH (4.02 to 3.24) and density (1.23001g.L-1 to 1.01726 g.L-1, and an increase in titratable acidity (2.04 to 3.05 g.L-1 ). In the kombucha formulations with the addition of camu-camu, a reduction in the pH of samples B and D was observed (from 3.24 to 2.62), as well as an increase in acidity (3.07 to 5.68 g.L-1and alcoholic content (0.50% to 1.04% v/v) compared to the original kombucha. On the other hand, the addition of bitter ginger (sample C) only influenced the alcoholic content, resulting in a difference of 0.25% higher than the original kombucha. Furthermore, the camu-camu formulations (B and D) showed the highest DPPH inhibition results (90.89% and 90.32%, respectively). Regarding ABTS, these same samples also demonstrated a high percentage of inhibition (100.71% and 87.5%, respectively). Another relevant result with the addition of the camu-camu fruit was the total phenolic content, which reached 120.9 mg.100g-1in sample B and 95.0 mg.100g-1in sample D. In contrast, the flavonoid content was higher in the samples with bitter ginger extract (20.4 mg.100g-1in sample C). Microbiological analyses indicated the absence of total and thermotolerant coliforms in the samples. Yeast populations were higher in the formulations containing camu-camu and lower in the one containing only ginger. The kombuchas formulated with camu-camu and bitter ginger exhibit functional potential.