Bruna Klein

Lipid stability during the frozen storage of fillets from silver catfish exposed in vivo to the essential oil of Lippia alba (Mill.) NE Brown.

BACKGROUND Lippia alba is effective in sedating and reducing stress to fish during transportation. Because some in vitro studies have demonstrated the antioxidant activity of L. alba, we hypothesized that its use in vivo could result in antioxidant effects post mortem. Therefore, in this study we evaluated whether the essential oil of L. alba (EO) used as sedative for fish transport would increase the lipid stability of fillets from silver catfish during frozen storage. RESULTS The exposure to the EO in vivo did not affect conjugated diene values. However, EO (30 and 40 µL L(-1)) delayed the peak formation of peroxides (from the third to the sixth month of storage) and thiobarbituric reactive substances (from the ninth to the twelfth month of storage) when compared to control fillets. After exposure to 40 µL L(-1) EO the free fatty acid content was higher than for control at the start of fillet storage, with no differences among groups thereafter. CONCLUSION The essential oil of L. alba used as sedative in the water to transport silver catfish can delay lipid oxidation of fillets during frozen storage. Thus L. alba may be a promising source of natural active compounds for use in aquaculture and the food industry.

Using the essential oil of Aloysia triphylla (L'Her.) Britton to sedate silver catfish (Rhamdia quelen) during transport improved the chemical and sensory qualities of the fish during storage in ice.

UNLABELLED Exposure of silver catfish to 40 μL/L of the essential oil of Aloysia triphylla (AT) during in vivo transport delayed the onset and resolution of rigor mortis as well as the degradation of IMP into HxR compared to the control. The fish that were treated with 30 or 40 μL/L of AT received lower sensory demerit scores after 10 d of storage in ice compared to the control, and the fish that were treated with 40 μL/L of AT had a longer sensory shelf life than did the control. These results indicated that using AT as a sedative in the water in which the silver catfish were transported extended their freshness and increased their shelf life during refrigerated storage. PRACTICAL APPLICATION Interest in natural anesthetics, such as Aloysia triphylla, has increased in the field of commercial aquaculture because they reduce the number of fish lesions acquired during capture, handling, and transportation. Fish sedated with the essential oil of A. triphylla at 40 μL/L during transport before slaughter exhibited a delay in the loss of freshness and an increased shelf life in ice. In addition to improving animal welfare before slaughter, the essential oil appears to be a promising product for improving fish conservation in the food industry.

Evaluation of Stability and In Vitro Security of Nanoemulsions Containing Eucalyptus globulus Oil

Essential oil of Eucalyptus globulus presents several pharmacological properties. However, their therapeutic efficacy may be affected by limitations due to several conditions, rendering it difficult to obtain stable and effective pharmaceutical formulations. The use of nanotechnology is an alternative to improve their characteristics aiming to ensure their stability and effectiveness. Furthermore, studies about the possible toxic effects of nanostructures are necessary to evaluate safety when the formulation comes into contact with human cells. Hence, in this paper, we evaluate for the first time the stability and in vitro cytogenotoxicity of nanoemulsions containing Eucalyptus globulus in peripheral blood mononuclear cells. As a result, the stability study found that the best condition for storage up to 90 days was refrigeration (4°C); it was the condition that best preserved the nanometric features. The content of the major compounds of oil was maintained after nanoencapsulation and preserved over time. In tests to evaluate the safety of this formulation, we can conclude that, at a low concentration (approximately 0.1%), Eucalyptus globulus nanoemulsion did not cause toxicity in peripheral blood mononuclear cells and also showed a protective effect in cells against possible damage when compared to oil in free form.

Production, Characterization, and Stability of Orange or Eucalyptus Essential Oil/β-Cyclodextrin Inclusion Complex.

The aim of this study was to produce and characterize inclusion complexes (IC) between β-cyclodextrin (β-CD) and orange essential oil (OEO) or eucalyptus essential oil (EEO), and to compare these with their pure compounds and physical mixtures. The samples were evaluated by chemical composition, morphology, thermal stability, and volatile compounds by static headspace-gas chromatography (SH-GC). Comparing the free essential oil and physical mixture with the inclusion complex, of both essential oils (OEO and EEO), it was observed differences occurred in the chemical composition, thermal stability, and morphology. These differences show that there was the formation of the inclusion complex and demonstrate the necessity of the precipitation method used to guarantee the interaction between β-CD and essential oils. The slow loss of the volatile compounds from both essential oils, when complexed with β-CD, showed a higher stability when compared with their physical mixtures and free essential oils. Therefore, the results showed that the chemical composition, molecular size, and structure of the essential oils influence the characteristics of the inclusion complexes. The application of the β-CD in the formation of inclusion complexes with essential oils can expand the potential applications in foods.

Application of electrolyzed water for improving pork meat quality

The microbiological and oxidative qualities of pork loin sprayed with different types (slightly acidic, acidic and basic) and combinations of electrolyzed water (EWs) were evaluated. The EWs were applied at two temperatures (18° and 30°C) and pressures (30 and 45psi) and the volume corresponded to approximately 10% water commonly used in carcass washing. EW after spraying exhibited a chlorine concentration between 15 and 25ppm. The application of acidic EW (AEW) alone or in combination with basic EW (BEW) decreased (P<0.05) the microbial counts shortly after spraying. In addition, the combination of BEW+AEW (30psi) reduced the mesophilic and psychrotrophic bacteria counts throughout the refrigerated storage (P<0.05). The EWs did not increase the lipid oxidation of the samples. On the other hand, a high protein oxidation was observed in the samples sprayed with AEW and slightly acidic EW (SAEW), while BEW was effective to reduce the oxidation reactions. Therefore, the results showed that the combination BEW+AEW may be a viable alternative to reduce the volume of water used at slaughter and to improve the microbiological quality of pork meat.

Antibiofilm activity of nanoemulsions of Cymbopogon flexuosus against rapidly growing mycobacteria

Rapidly growing mycobacteria (RGM) are opportunistic microorganisms that can cause both local and disseminated infections. When in biofilm, these pathogens become highly resistant to antimicrobials used in clinical practice. Composed abundantly of polymeric substances, biofilms delay the diffusion of antimicrobials, preventing the drug from penetrating the deeper layers and having an effective action. Therefore, the search for new and alternative therapeutic options has become of fundamental importance. Natural products fall into these options, especially essential oils. However, these oils present problems, such as low miscibility in water (which decreases its bioavailability) and degradation by light and temperature. Thus, the objective of this work was to explore the action of free essential oil and nanoemulsions of Cymbopogon flexuosus on strains of RGM, in planktonic and sessile forms. In this work, standard strains of Mycobacterium fortuitum (ATCC 6841), Mycobacterium massiliense (ATCC 48898) and Mycobacterium abscessus (ATCC 19977) were used. The susceptibility of the microorganisms in planktonic form was obtained by conventional microdilution techniques and by cell viability curve. The analysis of the antibiofilm activity was performed by a semi-quantitative macrotechnique. The nanoemulsion exhibited significant antimicrobial activity, with minimum inhibitory concentration values lower than those presented by the free essential oil, against strains in the planktonic state. However, both were efficient in destroying the already formed biofilm, whereas only the free oil inhibited the formation of mycobacterial biofilm. This study demonstrated the therapeutic potential of C. flexuosus essential oil, especially in its nanostructured form, which can be demonstrated against infections caused by rapidly growing mycobacteria.

Nanoemulsions containing Cymbopogon flexuosus essential oil: Development, characterization, stability study and evaluation of antimicrobial and antibiofilm activities

The increase of microbial resistance generates the search for new substances with antimicrobial potential. The essential oil of Cymbopogon flexuosus (Lemongrass) stands out in the literature for its antimicrobial, insecticide and antioxidant properties, but it has high volatilization and low stability, and the nanoencapsulation of this oil could be an alternative to overcome these limitations. Thus, the objective of this study was to develop, for the first time, nanoemulsions containing the essential oil of C. flexuosus, through a method that does not use organic solvent and with temperature control to avoid the volatilization of the oil, characterize and evaluate of stability and the antimicrobial and antibiofilm activities of these nanoemulsions. Nanoemulsions presented adequate physicochemical characteristics (average size less than 200 nm, polydispersity index less than 0.3, negative zeta potential and acid pH) which were maintained during 90 days of storage, and the nanoencapsulation of the C. flexuosus oil enhanced its therapeutic efficacy against the microorganisms evaluated in this study compared to the free oil. These results are very promising because among the microorganisms that the nanoemulsion containing C. flexuosus was able to inhibit the formation of biofilm are the bacteria Pseudomonas aeruginosa and Staphylococcus aureus, which were recently listed by the World Health Organization as priority pathogens for development of new antibiotics.

Development of dispersive solvent extraction method to determine the chemical composition of apple peel wax

A method to extract apple peel wax was developed using the dispersive solvent extraction technique and applied to four apple cultivars (Royal Gala, Pink Lady®, Red Delicious, and Granny Smith). Different variables of the method were optimized, namely type and volume of extraction and dispersive solvents, ionic strength, and use of ultrasound. Extracts were evaluated as gravimetric yield of wax and composition as determined by gas chromatography. Optimized conditions provided yields higher than 95%. In a repeatability assay, the relative standard deviation for the extracted wax content was <3%. Thirty-one wax compounds were identified, among them fatty acids, hydrocarbons, sterols, and terpenes. Fatty acids were the major constituents in the analyzed extracts. N-alkane, nonacosane, and triterpene ursolic acid were also significant constituents. The method allows the determination of the total peel wax content and the different constituents of this fraction from distinct apple cultivars.

Fungicides in red wines produced in South America

ABSTRACT Although recent research has shown that pesticides can remain in wine, there is only legislation regarding the level of pesticides in grapes; no such regulations exist for wine. Therefore, the objective of this work was to evaluate the presence of fungicides in 190 wines produced in southern South America, as well as to present a new method for the quantification of dithiocarbamates. The fungicides were analysed by LC-MS/MS and GC/MS using validated methods according to the SANTE recommendations. The results for dithiocarbamates are expressed in mancozeb equivalents and are reported herein for the first time. Of the 190 wines analysed, 40% had residues from at least one fungicide detected above the LOQ, and 16.3% of the wines contained levels of fungicides above the MRL for grapes. The fungicides most commonly found were dithiocarbamates, azoxystrobin, carbendazim, difenoconazole, dimethomorph and cyprodinil. The new method for quantification of dithiocarbamates presented high accuracy (89.8–108.1%) and precision (HorRat values between: 0.5 – 1.1). GRAPHICAL ABSTRACT