Active packaging of poly(lactic acid) nanofibers and essential oils with antifungal action on table grapes.

The table grape is a non-climateric fruit that is very susceptible to fungal contamination, in addition to suffering an accelerated loss of quality during storage. The in vitro and in grape antifungal and antiocratoxigenic effects of the essential oils from Alpinia speciosa and Cymbopogon flexuosus against Aspergillus carbonarius and Aspergillus niger were studied. The oils were encapsulated in poly(lactic acid) (PLA) nanofibers as a potential active packaging to be applied to control the degradation of grapes stored during the post-harvest period. Fungal proliferation and ochratoxin A synthesis in A. carbonarius and A. niger decreased in the presence of the active packaging. However, the nanofiber containing the essential oil from C. flexuosus was more efficient in providing a fungicidal effect against A. carbonarius (10% and 20%) and A. niger (20%). In addition, weight loss and color changes were controlled and the parameters of acidity, °Brix, softening and the texture of the grape were maintained. A very small mass loss of the essential oils encapsulated in nanofibers was observed by thermogravimetric analysis, showing that the nanofiber was efficient in enabling the controlled release. The quality and safety of table grapes were maintained for longer periods of storage in the presence of active packaging, so the incorporation of these oils in nanofibers can be a promising way to increase the shelf life of grapes.

Kinetic, thermodynamic and physical-chemical study of the removal of copper from cachaça using coconut fibers.

The use of coconut fiber as a copper adsorbent in cachaça was optimised, and changes in the chemical quality of the beverage were observed by analytical techniques. The influence of the adsorbent mass and copper concentration parameters was investigated using the Central Composite Design, and the optimum condition was obtained through the use of Response Surface Methodology. The equilibrium of the adsorption reaction was obtained within 120 min. The kinetic data were better adjusted for the Elovich model (Elovich and Zhabrova 1939) and the isotherm data for the Sips model (Sips 1948). The maximum adsorption capacity was 1.38 mg g-1. Slight changes in the physicochemical quality of the beverage were observed, including a decrease in volatile acidity and alcohol content. Copper levels in cachaça decreased from 8.57 mg L-1 to 4.97 mg L-1 after adsorption. Therefore, the use of biomass as a metal ion adsorbent in beverages can be successfully employed.

Antifungal and physicochemical properties of Ocimum essential oil loaded in poly(lactic acid) nanofibers.

Poly(lactic acid) (PLA) nanofibres containing different proportions of the essential oils from Ocimum basilicum L. and Ocimum gratissimum L. were prepared by solution blow spinning method. The essential oils were extracted by hydrodistillation and characterized by gas chromatography. MEV, contact angle, DSC and FTIR were used to characterize the nanofibres. The effect of bioative nanofibres on the growth of the fungus and on the production of ochratoxin A were evaluated using the fumigation test. Linalool, 1·8-cineole and camphor were the principal components of the essential oil from O. basilicum, and eugenol was the principal constituent in the oil from O. gratissimum. An increase in the average diameter of the nanofibres was observed with the addition of the essential oils. The essential oils acted as a plasticizer, resulting in a reduction in the crystallinity of the PLA. The encapsulation of essential oils in PLA nanofibres was verified by FTIR. An effective antifungal and antimicotoxygenic activity against Aspergillus ochraceus and Aspergillus westerdjikiae was observed for the bioative nanofibres. These results confirm the potential of PLA nanofibres containing the essential oils for the control of toxigenic fungi that cause the deterioration of food and are harmful to human health.

Acaricidal and repellent activity of the essential oils of Backhousia citriodora, Callistemon viminalis and Cinnamodendron dinisii against Rhipicephalus spp.

The ticks Rhipicephalus microplus and Rhipicephalus sanguineus sensu lato (s.l) are of great importance to agriculture, veterinary medicine and public health. Due to a number of problems related to the use of synthetic acaricides, natural products emerge as promising substances for alternative tick control. In the present study, essential oils of Backhousia citriodora, Callistemon viminalis and Cinnamodendron dinisii were extracted by hydrodistillation, characterized by GC-MS and GC-FID and biologically evaluated for acaricidal activity against R. microplus and repellent activity against R. sanguineus s.l. Inhibition of acetylcholinesterase (AChe) by the essential oils was also evaluated. The major constituent of B. citriodora is citral (98.9 %), whereas the essential oil from C. viminalis is rich in 1.8-cineole (78.1 %), α-pinene (12.5 %) and limonene (3.36 %), and that from C. dinisii contains α-pinene (30.8 %), ß-pinene (12.5 %) and sabinene (11.3 %) as the principal constituents. The median lethal concentrations (LC 50) estimated for the essential oils on engorged R. microplus females were 3.276 µL.mL-1 for B. citriodora, 8.195 µL.mL-1 for C. dinisii and 8.936 µL.mL-1 for C. viminalis. The essential oil of B. citriodora showed the best repellent effect against unfed R. sanguineus s.l. adults, demonstrating repellent action up to 3 h after application. The essential oil of C. viminalis was able to reduce AChe activity, with an average inhibitory concentration (IC 50) of 0.33 µg mL-1. Thus, these oils can be considered as sources of bioactive compounds for tick control.

Effect of the essential oils of Satureja montana L., Myristica fragrans H. and Cymbopogon flexuosus S. on mycotoxin-producing Aspergillus flavus and Aspergillus ochraceus antifungal properties of essential oils.

Essential oils can be a useful alternative to the use of synthetic fungicides because they have biological potential and are relatively safe for food and agricultural products. The objectives of the present study were to evaluate the antifungal and antimycotoxigenic activities of the essential oils from Satureja montana L., Myristica fragrans H. and Cymbopogon flexuosus S. against Aspergillus flavus and Aspergillus ochraceus, as well as their effects on ergosterol synthesis and membrane morphology. The antifungal potential was evaluated by mycelial growth analysis and scanning electron microscopy. Fungicidal effects against A. flavus, with MFC of 0.98, 15.62 and 0.98 µL/mL, respectively, were observed for the essential oils from S. montana, M. fragrans and C. flexuosus. Aspergillus ochraceus did not grow in the presence of concentrations of 3.91, 15.62 and 0.98 µL/mL of the essential oils from S. montana, M. fragrans and C. flexuosus, respectively. The essential oils significantly inhibited the production of ochratoxin A by the fungus A. ochraceus. The essential oils also inhibited the production of aflatoxin B1 and aflatoxin B2. The biosynthesis of ergosterol was inhibited by the applied treatments. Biological activity in the fungal cell membrane was observed in the presence of essential oils, given that deleterious effects on the morphologies of the fungi were detected. The essential oils under study are promising as food preservatives because they significantly inhibit toxigenic fungi that contaminate food. In addition, the essential oils hindered the biosynthesis of mycotoxins.

Mechanism of action of various terpenes and phenylpropanoids against Escherichia coli and Staphylococcus aureus.

Foodborne, disease-causing microorganisms are increasingly resistant to commercial antibiotics. Thus, there is a need for the development of new agents capable of acting efficiently in the control of these pathogens. Terpenoids and phenylpropanoids stand out for having high biological activity and a broad spectrum of action. The objectives of this study were to evaluate the antibacterial potential of limonene, ß-citronellol, carvone, carvacrol, eugenol and trans-cinnamaldehyde and to investigate the mechanism of activity of these compounds against the bacteria Escherichia coli and Staphylococcus aureus. The terpene and phenylpropanoid compoundswere purchased and their antibacterial potential was assessed by macrodilution. The mechanism of action was verified by tests of potassium ion efflux, salt tolerance, extravasation of cellular contents, absorption of crystal violet and morphological changes analyzed by electron microscopy. Bacteriostatic and bactericidal effects caused by the compounds carvone, carvacrol, eugenol and transcinemaldehyde were observed in both species; antibacterial activity against only S. aureus was observed for ß-citronelol and limonene. Reduced salt tolerance was found for strains of E. coli treated with carvacrol and S. aureus treated with ß-citronelol. There was extravasation of cellular materials induced by treatments with carvone, carvacrol, eugenol and trans-cinnamaldehyde in both microorganisms. The absorption of crystal violet increased for E. coli after incubation with each treatment. Deleterious effects and morphological changes were observed. Therefore, the monoterpenes and phenylpropanoids under study are potentially applicable for antimicrobial use against E. coli and S. aureus, and the mechanism of action involves changes in membrane permeability without cell lysis.

Eucalyptus grandis and Eucalyptus microcorys Essential Oils: in vitro Modulation of Hemostasis and Genotoxic Activity

Abstract The genus Eucalyptus present high content of essential oil (EO). This study evaluated the pharmacological properties of Eucalyptus grandis (EG) and Eucalyptus microcorys (EM) EOs. The major component in both EOs was 1,8-Cineole. Both essential oils prevented thrombus dissolution and reduced clotting, hemolysis, and genotoxicity induced by snake venoms. 50% (EM) and 73% (EG) were the greatest inhibitions obtained in the thrombolytic assay - thrombolysis induced by B. moojeni venom. Increases in clotting time were also observed, with values considered significant between 10-27 seconds. Lysis values 50% lower than the negative control were observed in both EOs. The EOs also protected fibrinogenolysis induced by snake venom. EM EO was more effective in reducing venom-induced DNA fragmentation in the comet assay, with arbitrary unit values 66.15% lower than the positive control. These oils present wide application potential considering the pharmacological properties observed in this study.

Identification of volatile compounds, quantification of glycerol and trace elements in distilled spirits produced in Mozambique.

Distilled spirits, in addition to satisfying the legal requirements with respect to its composition, must possess a sensorial quality capable of satisfying its consumers. The present work describes the analysis of volatile compounds, trace elements and glycerol in thirteen samples of Mozambican spirits collected in different regions of the country. Extraction of volatile components was a accomplished using the headspace SPME technique, the quantification of glycerol was achieved by UV/Vis spectroscopy and the determination of trace elements by atomic absorption spectrometry. Of the 35 volatile compounds identified, 19 were esters, of which ethyl hexanoate, ethyl octanoate, ethyl nonanoate, ethyl decanoate, ethyl laurate, ethyl hexadecanoate, ethyl tetradecanoate, ethyl benzenepropanoate, 3-methylbutyl acetate and isoamyl alcohol were the predominant compounds found in the different samples, contributing to the characteristics and aroma of the beverages. As for glycerol, concentrations below 5 mg L-1 were observed in all the samples studied. The samples were found to be contaminated by metals such as copper, lead and zinc. In addition, the results provided information on the quality of Mozambican spirits regarding some aspects related to the determination of metals and glycerol. This information might stimulate producers to be more attentive to the conditions of production and the risks involved in achieving good quality spirits.