Essential Oil from the Leaves, Fruits and Twigs of Schinus terebinthifolius: Chemical Composition, Antioxidant and Antibacterial Potential.

Schinus terebinthifolius Raddi, popularly known as "Pink pepper", is a plant native to Brazil. The objective of this work was to analyze the chemical composition and the antioxidant and antibacterial potential of essential oils (EOs) from the leaves, fruits and twigs of S. terebinthifolius, aiming for their application in food safety. EOs were obtained by hydrodistillation and the chemical composition was determined by gas chromatography coupled to mass spectrometry. Phenolic compounds were quantified and antioxidant activity was evaluated using three different methods. The antibacterial activity was determined by the broth microdilution method against foodborne bacteria. In the chemical analysis, 22 compounds were identified in the leaves, 13 compounds in the fruits and 37 compounds in the twigs, revealing the presence of the main compounds germacrene D (12.04%, 15.78%, 20,41%), caryophyllene (15.97%, 3.12%, 11.73%), α-pinene (11.6%, 17.16%, 2.99%), ß-pinene (5.68%, 43.34%, 5.60%) and γ-gurjunene (16,85%, 3,15%) respectively. EOs showed better antioxidant potential using the ß-carotene/linoleic acid method with 40.74, 61.52 and 63.65% oxidation inhibition for leaves, fruits and twigs, respectively. The EO from the leaves showed greater antibacterial potential against Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 0.62 mg mL-1, a value lower than the MIC of sodium nitrite (5.00 mg mL-1), the antimicrobial standard synthetic. The activities of pink pepper EOs suggest their potential as a biopreservative in foods.

Physicochemical, antioxidant, rheological, and sensory properties of juice produced with guava pulp and peel flour.

Juice formulations containing guava pulp and different amounts (0%, 1%, 3%, and 5%) of its by-product flour (GBF) were developed and evaluated for antioxidant activity, total phenolic compounds, physicochemical, rheological, microbiological and sensorial parameters. The GBF addition to guava juice increased the acidity and altered the color and rheological parameters, especially at higher levels (3% and 5%). There was an increase in the content of dietary fiber, anthocyanins and antioxidant activity with GBF addition, but no changes occurred in the soluble solids, total phenolic compounds, and ascorbic acid content. The guava juice containing 1% GBF received better sensory scores when compared with the 3% and 5% GBF formulations. Storage at 4o C for 21 days affected most of the parameters examined, but the microbiological parameters remained stable. Shelf life of 14 days is recommended to maintain the physicochemical and antioxidants characteristics of guava juice.

Evaluation of the antibacterial activity of Piperaceae extracts and nisin on Alicyclobacillus acidoterrestris.

Alicyclobacillus acidoterrestris is a gram-positive aerobic bacterium. This bacterium resists pasteurization temperatures and low pH and is usually involved in the spoilage of juices and acidic drinks. The objective of this study was to evaluate the antibacterial activities of nisin and the species Piper (Piperaceae) on A. acidoterrestris. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined by the broth microdilution method. The species Piper aduncum had the lowest MIC and an MBC of 15.6 µg/mL and was selected for fractionation. Six fractions were obtained, and the dichloromethane fraction (F.3) had the lowest MIC/MBC (7.81 µg/mL). The dichloromethane fraction was again fractionized, and a spectral analysis revealed that the compound was prenylated chromene (F.3.7). The checkerboard method demonstrated that the crude extract (CE) of P. aduncum plus nisin had a synergistic interaction (fractional inhibitory concentration [FIC] = 0.24). The bactericidal activity of (F.3.7) was confirmed by the time-kill curve. P. aduncum, nisin, and prenylated chromene exhibited strong antibacterial activity against the spores and vegetative cells of A. acidoterrestris. The results of this study suggest that extracts of the genus Piper may provide an alternative to the use of thermal processing for controlling A. spoilage.