Development of alcohol vinegars macerated with ACAI (Euterpe precatoria Mart.) berries and their quality evaluations with emphasis on color, antioxidant capacity, and volatiles profile.

In this work, the Amazonian native acai fruit, a superfruit recognized worldwide, was used through a simple operation of maceration in alcohol vinegar to transform it into an attractive and functional product containing the acai natural colorant and its bioactive compounds. The variables studied were the proportion of alcohol vinegar to acai (8:2 and 1:1) and maceration period (7, 14, and 21 days). The final vinegar was subjected to the determination of color parameters, antioxidant capacity (DPPH, ABTS), total phenolics content (TPC), volatile compounds extracted by stir bar sorptive extraction and identified by gas-chromatography-mass spectrometry analysis. The alcohol vinegars macerated with acai presented the color according to the content of acai added and maceration period employed, whereas antioxidant capacity and TPC were comparable to vinegars elaborated from fruits and red wine. Sixty volatiles compounds classified into five chemical groups were identified. The principal volatile compounds which contributed to the aroma in the products were 3-methyl-1-butanol, phenylethyl alcohol, benzaldehyde, o-cymene, p-cymenene, isoamyl acetate, and ethyl acetate. The most attractive product regarding the parameters studied was obtained from the use of the proportion of 1:1 of alcohol vinegar:acai and maceration period of 14 days. This product retained the most similar color to acai in natura, the highest values for antioxidant capacity measured by ABTS and TPC while being rich in volatile compounds due to the contributions mainly of alcohols, esters, aldehydes, and terpenes. PRACTICAL APPLICATION: This work demonstrates the feasibility to produce an alcohol vinegar with an attractive color and functional properties by the addition of acai resulting in to a wide spectrum of chemical compounds of acai through a very simple operation of maceration during 14 days of a proportion of 1:1 of alcohol vinegar:acai.

Alcoholic beverages from araçá-boi fruit: quantification of antioxidant compounds by NMR ERETIC2.

Fermentation is a preservation process responsible for increasing food product shelf life. In this context, alcoholic fermentation can add value to unconventional Amazon fruits, e.g., araçá-boi (Eugenia stipitata). This fruit has various antioxidant phenolic compounds with well-known nutraceutical properties. However, araçá-boi is still underexplored by food industry. This rationale led to investigate the influence of five commercial yeasts (Saccharomyces cerevisiae) and filtration process on chemical composition and antioxidant capacity of araçá-boi beverages. DPPH and Folin Ciocalteu assays were used to determine antioxidant capacity and total phenolic content. Organic compounds' contents were assessed by NMR-ERETIC2. In all beverages, ten compounds [tyrosol, sucrose, fructose, (α/ß)-glucose, ethanol, malic, citric, gallic, and succinic acids] were identified and quantified. The highest phenolic concentrations [gallic acid (390.0 µM) and tyrosol (380.0 µM)] were found in Biolievito Bayanus (BBA) beverage. The new BBA beverage was used for investigating filtration process influence on chemical composition and antioxidant responses. Alcoholic content (unfiltered: 13.9°GL and filtered: 12.7°GL), antioxidant responses, and total phenolic contents were influenced by filtration process. The yeast type and unfiltered process were determinant for chemical content and antioxidant capacity of beverages. These results might be useful to private sector and future production and commercialization of araçá-boi beverages.