The essential oil of basil (Ocimum basilicum) has significant biological activity against insect pests and can be extracted through various techniques. This work aimed to optimize and validate the extraction process of the essential oil of O. basilicum submitted to different drying temperatures of the leaves and extracted by the combination of a Clevenger method and ultrasound. The biological activity of the extracted oil under different conditions was evaluated for potential control of Sitophilus zeamais. The extraction method was optimized according to the sonication time by ultrasound (0, 8, 19, 31 and 38 min) and hydrodistillation (20, 30, 45, 60 and 70 min) and drying temperature (20, 30, 45, 60 and 70 °C). The bioactivity of the essential oil was assessed against adults of S. zeamais and the effects of each variable and its interactions on the mortality of the insects were evaluated. The best yield of essential oil was obtained with the longest sonication and hydrodistillation times and the lowest drying temperature of leaves. Higher toxicity of the essential oil against S. zeamais was obtained by the use of ultrasound for its extraction. The identification and the relative percentage of the compounds of the essential oil were performed with a gas chromatograph coupled to a mass selective detector. The performance of the method was assessed by studying selectivity, linearity, limits of detection (LOD) and quantification (LOQ), precision and accuracy. The LOD and LOQ values for linalool were 2.19 and 6.62 µg mL⁻¹ and for estragole 2.001 and 6.063 µg mL⁻¹, respectively. The coefficients of determination (R²) were >0.99. The average recoveries ranged between 71 and 106%, with coefficient of variation ≤6.4%.

Essential oils (EOs) are widely recognized as efficient and safe alternatives for controlling pest insects in foods. However, there is a lack of studies evaluating the toxicological stability of botanical insecticides in stored grains in order to establish criteria of use and ensure your efficiency. The objective of this work was to evaluate the toxicological stability of basil essential oil (O. basilicum) and its linalool and estragole components for Sitophilus zeamais (Motschulsky) adults in corn grains by fumigation. The identification of the chemical compounds of the essential oil was performed with a gas chromatograph coupled to a mass selective detector. Mortality of insects was assessed after 24 h exposure. After storage for six (EO) and two months (linalool and estragole) under different conditions of temperature (5, 20, and 35 °C) and light (with and without exposure to light), its toxicological stability was evaluated. Studies revealed that the essential oil of O. basilicum and its main components exhibited insecticidal potential against adults of S. zeamais. For greater toxicological stability, suitable storage conditions for them include absence of light and temperatures equal to or less than 20 °C.

Bioinsecticides are regarded as important alternatives for controlling agricultural pests. However, few studies have determined the persistence of these compounds in stored grains. This study aimed at optimizing and validating a fast and effective method for extraction and quantification of residues of safrole (the main component of Piper hispidinervum essential oil) in cowpea beans. It also sought to assess the persistence of this substance in the grains treated by contact and fumigation. The proposed method used headspace solid-phase microextraction (HS-SPME) and gas chromatography with a flame ionization detector (GC/FID). Factors such as temperature, extraction time and type of fiber were assessed to maximize the performance of the extraction technique. The performance of the method was appraised via the parameters selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, and accuracy. The LOD and LOQ of safrole were 0.0057 and 0.019 μg kg⁻¹, respectively and the determination coefficient (R²) was >0.99. The relative recovery ranged from 99.26 to 104.85, with a coefficient of variation <15%. The validated method was applied to assess the persistence of safrole residue in grains, where concentrations ranged from 1.095 to 0.052 µg kg⁻¹ (contact) and from 2.16 to 0.12 µg kg ⁻¹ (fumigation). The levels measured up from the fifth day represented less than 1% of the initial concentration, proving that safrole have low persistence in cowpea beans, thus being safe for bioinsecticide use. Thus, this work is relevant not only for the extraction method developed, but also for the possible use of a natural insecticide in pest management in stored grains.

Food contamination by Salmonella poses a significant public health risk, rendering products unfit for consumption. This study aimed to evaluate the efficiency of ozone gas (O₃), applied in flow and at low pressures, in inactivating Salmonella on black peppercorns (Piper nigrum L.). Samples were inoculated with a cocktail of four Salmonella serotypes and subjected to ozonation under flow or low-pressure conditions in a hypobaric chamber. For the flow treatment, ozone gas at 16 mg L⁻¹ was humidified by passing it through a 40% (w/v) sodium chloride solution and applied for 2, 4, and 8 h. For the hypobaric chamber treatment, an inlet O₃ concentration of 60 mg L⁻¹ was used, with 10, 15, and 20 injections. The results showed that, under flow ozonation for 8 h, Salmonella was absent in 25 g of the sample. Ozone treatment increased pH, total titratable acidity (TTA), antioxidant activity (DPPH*), lightness (L*), color saturation (C*), total phenolic content (TPC), and the concentration of major essential oil compounds in all treatments. Under low-pressure ozonation, Salmonella persisted in all tested conditions, along with changes in color difference (∆E*), moisture content, TTA, DPPH*, L*, C*, pH, TPC, and the concentration of major essential oil compounds. The essential oil yield was not affected. Although the application of ozone at low pressures reduced Salmonella contamination, it was not sufficient for complete inactivation under the tested conditions. However, the flow-applied ozone treatment proved effective in the inactivation of Salmonella in black peppercorns.