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In this study, different phenolic extracts were obtained from the jaboticaba skin meal (JSM), whose phenolic compounds were characterized and their antibacterial activities were assessed. Moreover, the activity of lyophilized ethanolic extract of jaboticaba skin (EEJS) on wound healing was analyzed in rats. The JSM phenolic extracts were obtained in four ways: aqueous, methanolic, ethanolic, and acetone extracts. The phenolic compounds were characterized in these extracts by high-performance liquid chromatography, and their antibacterial activities were evaluated. The in vivo experiment was divided into four groups and received the following treatments: G1-silver sulfadiazine (positive control); G2-EEJS at 10%; G3-EEJS at 5%, and G4-EEJS at 2.5%. The aqueous extract did not inhibit the growing of any bacterium. The ethanolic, acetone, and methanolic extracts inhibited the growing of all bacteria tested at the concentrations of 1.25%, 2.50%, and 5.00%, respectively. The ethanolic extract was the one that showed the highest bacterial inhibition potential and the highest contents of phenolic compounds, especially of catechin, epicatechin gallate, and epicatechin. The G3 and G4 treatments presented faster wound healing compared to the G1 one, as it promoted a less intense inflammatory reaction and full closure of the wounds at an accelerated rate.

PurposeThe main purpose of this paper was to evaluate the influence of the zein coating containing essential oils on the sensory characteristics of sodium-reduced mozzarellas.Design/methodology/approachMozzarellas were prepared by dipping in brine containing 5, 10, 15 or 20% of NaCl (w/v) that correspond, respectively, to 25, 50, 75 and 100% of NaCl content used in industry. These salted mozzarellas and another one, unsalted, were coated by an edible zein film added with 3% of a mixture of thyme and garlic essential oils (1:1). They were subjected to sensory analysis in relation to salty taste and overall impression. The mozzarella without salt reduction (20% NaCl w/v), coated or uncoated with the edible film, was also subjected to the analysis of water loss and microbiological quality, in order to evaluate the impact of this film on product quality.FindingsThe zein coating added with oils did not compromise the sensory acceptance of the mozzarella prepared with up to 50% of salt reduction. Water loss and microbial growth were lower in zein-coated mozzarella than in uncoated mozzarella. These results showed that this film could be applied as natural additive, contributing to the microbiological and sensory characteristics of the mozzarella.Originality/valueThis paper contributes to reducing the lack of studies in relation to new technologies for food preservation and sodium reduction. In addition, the zein coating containing essential oils can be tested on other food categories.

The homologous and heterologous adaptation capacity of L. monocytogenes and L. innocua were determined for thyme, oregano and nutmeg essential oils, as well as their adaptation capacities to acidic stress. Minimum bactericidal concentrations (CMB) and minimum inhibitory and minimum growth pH, were established. The capacity for increased tolerance to essential oils and acidic stress, along with heterologous adaptation among the essential oils tested and to acidic pH was determined, and that between pH and essential oils. L. monocytogenes and L. innocua adapted to all essential oils and to the minimum inhibitory pH, after exposition to sub-lethal conditions. Both strains presented heterologous adaptation capacity. After previous exposition to sub-lethal essential oil concentrations, the regenerated cells were capable of growth under 3.5 pH values, and increased CMB values. Essential oil CMBs for previously cultivated cells under minimum growth pH environments also increased, attaining values 1.6 times superior to previous ones.

Staphylococcus aureus causes food intoxication and can become resistant to a large number of drugs. Thus, there is a growing interest in understanding the mechanisms involved in the adaptation of bacterial cells to environmental stresses or to antimicrobial agents. In this context, we evaluated the cinnamaldehyde (CIN) MBC for two contaminating food strains of S. aureus (GL 5674 and GL 8702) and tested the hypothesis that the exposure of these strains to sublethal concentrations of CIN and pH could increase their resistance to this antimicrobial, to acid stress and also to stress at high temperatures. Thus, the ability of the strains to adapt to CIN and acid stress was evaluated, as well as the cross adaptation between acid stress and CIN. The strains GL 5674 and GL 8702 of S. aureus are sensitive to CIN in MBCs of 0.25% and 0.5% respectively, proving the antibacterial potential of this compound, but we proved the hypothesis of homologous adaptation to CIN. The strains grew in concentrations higher than the MBC after being previously exposed to sublethal concentrations of CIN. It was also observed heterologous adaptation of the strains, which, after exposure to the minimum pH of growth, were able to grow in concentrations greater than the MBC of CIN. GL 5674 showed greater adaptive plasticity, considerably reducing its minimum inhibitory pH and increasing its MBC after adaptation. Our results show a positive effect of adaptation to CIN, on the resistance of S. aureus (p <0.0001) to CIN, at a temperature of 37 ° C. However, in the absence of adaptation, the presence of CIN in S. aureus cultures maintained at 37 ° C, associated with increased exposure time showed an efficient bactericidal effect. Our results call attention to the conscious use of CIN as an antimicrobial agent and presents the possibility of using CIN, associated with the temperature of 37 ºC and the exposure time of 35 min, as a promising measure for the elimination of pathogenic strains .