Carvacrol-loaded nanoemulsions produced with a natural emulsifier for lettuce sanitization.

Carvacrol is an antimicrobial agent that shows potential for eliminating microorganisms in vegetables, increasing food safety. However, intense odor and low water solubility of carvacrol are limiting factors for its application for fresh vegetables sanitization, which can be overcome by nanotechnology. Two different nanoemulsions containing carvacrol (11 mg/mL) were developed by probe sonication: carvacrol-saponin nanoemulsion (CNS) and carvacrol-polysorbate 80 nanoemulsion (CNP). Formulations presented appropriate droplet sizes (from 74.7 nm to 168.2 nm) and high carvacrol encapsulation efficiency (EE) (from 89.5 % to 91.5 %). CNS showed adequate droplet size distribution (PDI < 0.22) and high zeta potential values (around -30 mV) compared to CNP, with saponin chosen for the following experiments. Carvacrol nanoemulsions presented Bacterial Inactivation Concentration (BIC) against the Salmonella cocktail from 5.51 to 0.69 mg/mL and for the E. coli cocktail from 1.84 to 0.69 mg/mL. Among all tested nanoemulsions, CNS1 presented the lowest BIC (0.69 mg/mL) against both bacterial cocktails. Damage to bacterial cells in lettuce treated with nanoemulsion was confirmed by scanning electron microscopy. For lettuce sanitization, CNS1 showed a similar effect to unencapsulated carvacrol, with a high bacterial reduction (>3 log CFU/g) after lettuce immersion for 15 min at 2 × BIC. Using the same immersion time, the CNS1 (2 × BIC) demonstrated equal or better efficacy in reducing both tested bacterial cocktails (>3 log CFU/g) when compared to acetic acid (6.25 mg/mL), citric acid (25 mg/mL), and sodium hypochlorite solution (150 ppm). Lettuce immersed in CNS1 at both concentrations (BIC and 2 × BIC) did not change the color and texture of leaves, while the unencapsulated carvacrol at 2 × BIC darkened them and reduced their firmness. Consequently, carvacrol-saponin nanoemulsion (CNS1) proved to be a potential sanitizer for lettuce.

Carvacrol encapsulation into nanoparticles produced from chia and flaxseed mucilage: Characterization, stability and antimicrobial activity against Salmonella and Listeria monocytogenes.

Carvacrol is a natural antimicrobial with excellent antimicrobial properties against several foodborne pathogens. Encapsulation can increase carvacrol stability and solubility, and mask its pronounced odor. Mucilages have been studied as wall material for nanoparticles due to their high retention capacity of bioactive compounds and ease of chemical modifications to improve their stability. In this study, 1.67 mg/mL of carvacrol encapsulated into chia mucilage nanoparticles (CMNP) and flaxseed mucilage nanoparticles (FMNP) were produced by high-energy emulsification technique and tested against Listeria monocytogenes and Salmonella. Encapsulation efficiency around 98% of carvacrol was obtained for both formulations. CMNP showed a diameter size of 179 nm and zeta potential of -11.4 mV. Bacterial Inactivation Concentration (BIC) of CMNP was 0.42 mg/mL against Salmonella and 0.83 mg/mL against L. monocytogenes. FMNP showed diameter size of 165.3 nm and zeta potential of -12.6 mV. BIC of FMNP was 0.83 mg/mL against both microorganisms. Scanning electron microscopy analysis showed that the nanoparticles are spherically shaped. Concentrations of BIC and ½ BIC were used to evaluate the kinetics of bacterial growth in the presence of antimicrobials (CMNP, FMNP and carvacrol solution). The results of this test showed that viable counts of Salmonella and L.monocytogenes were below the detection limit (1.69 log CFU/mL) after 2 h incubation (37 °C) using CMNP at the BIC. The wall material, rehydrated chia and flaxseed mucilages, reduced L. monocytogenes growth during 24 h. However, unloaded nanoparticles kept the viable counts of both microorganisms 2-5 log CFU/mL below the control curve of microbial growth during the 48 h experiment, suggesting that nanostructured mucilages potentiate antimicrobial properties. The results indicate that CMNP and FMNP have potential for use as food preservatives.

Low back pain: biopsychosocial aspects of chronic and acute pain / Lombalgias: aspectos biopsicossociais da dor crônica e da dor aguda

Chronic low back pain is a highly prevalent pathology, which has unclear associations with psychosocial aspects. This study investigated differences between patients with chronic low back pain (n = 25) and acute low back pain (n = 20) and verified the effect of the variables assessed on the pain mean. The design was cross-sectional, and the instruments applied were: sociodemographic interviews, Brief Pain Inventory, Beck Depression Inventory II, Hamilton Anxiety Rating Scale, Personality Factor Battery, Social Support Scale and Pain Catastrophizing Scale. The chronic pain group had significantly higher means of pain intensity, anxiety and catastrophic thoughts. In the regression analysis, the factor Depression of the Personality Factor Battery and belonging to the chronic pain group were found as predictors of the mean pain in the sample studied. It is understood that psychological factors are associated with the pain condition and require further investigation.

A lombalgia crônica é uma patologia de alta prevalência, que apresenta associações não esclarecidas com aspectos psicossociais. O estudo investigou diferenças entre pacientes com dor lombar crônica (n = 25) e aguda (n = 20), bem como verificou o efeito das variáveis avaliadas na média de dor. O delineamento foi transversal, e os instrumentos aplicados foram: entrevista sociodemográfica, Inventário Breve de Dor, Inventário Beck de Depressão II, Escala de Ansiedade de Hamilton, Bateria Fatorial de Personalidade, Escala de Apoio Social e Escala de Pensamentos Catastróficos sobre Dor. O grupo de dor crônica apresentou médias significativamente mais altas na intensidade da dor, na ansiedade e nos pensamentos catastróficos. Na análise de regressão, o fator Depressão da Bateria Fatorial de Personalidade e o fato de pertencer ao grupo de dor crônica foram encontrados como preditores da média de dor na amostra estudada. Entende-se que fatores psicológicos mostram-se associados ao quadro, sendo necessárias maiores investigações.