Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by alumi...Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by aluminum pillared clay (PILC). The PILCs displayed a total surface area of 270 m2/g, a total pore volume of 0.246 cm3/g and an average pore diameter of 8.9 A, which corresponds to the size of Al13 forming the pillars between the clay layers. The adsorption capacity shown by the PILCs for thymol from water is close to 319 mg?g-1 for low solid/liquid ratio (0.2%). This result suggests that the PILCs have both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PILCs. The experimental data were analyzed by the Freundlich and the Langmuir isotherm types for low values of equilibrium concentration. The rise of the isotherm in this range of concentrations was related to the affinity of thymol for clay sites, and the equilibrium data fitted well with the Freundlich model with maximum adsorption capacity of 319.51 mg/g for a ratio RS/L = 0.2%. Pseudo-first and pseudo-second-order kinetic models were tested with the experimental data and pseudo-first order kinetics was the best for the adsorption of thymol with coefficients of correlation R2 ≥0.986, and the adsorption was rapid with 90% of the thymol adsorbed within the first 20 min.展开更多
The high-water content of tomato predisposes it to spoilage by microorganisms and led producers to carry out traditional processing of tomatoes in the form of pasteurized tomato puree. However, rapid acidification of ...The high-water content of tomato predisposes it to spoilage by microorganisms and led producers to carry out traditional processing of tomatoes in the form of pasteurized tomato puree. However, rapid acidification of these traditional tomato purees is often observed. Then, the aim of this study was to evaluate the efficacy of the essential oil extracted from Clove (Syzygium aromaticum L.) in the improvement of traditional tomato puree producing technology. Essential oil of Clove (Syzygium aromaticum L.) was extracted by hydrodistillation and its chemical composition was determined by GC and GC/MS. Different types of traditional tomato puree were produced by the modification of the traditional processing technology and the addition of the essential oil introduction step, followed by manual stirring during the process. Based on previous studies, two different essential oil concentrations (5.0 and 7.5 μL∙g−1) were investigated. Physicochemical, microbiological and nutritional analyzes were performed in order to evaluate the quality of the traditional tomato puree produced. Results obtained revealed that the essential oil of Syzygium aromaticum investigated has a chemical composition characterized by the presence of eugenol (59.11%) and eugenol acetate (33.73%). Good stabilization of the physicochemical, microbiological and nutritional parameters in traditional tomato puree samples preserved with essential oil of Syzygium aromaticum were observed when compared to control. The essential oil of Clove, with his biological property, offers a novel approach to the management of traditional tomato puree during storage.展开更多
To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are th...To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are then able to express traits that facilitate ＂top-down＂ control of pests by attracting herbivore predators. Here we investigate the indirect defence mechanism of potato plants by analyzing the volatile patterns of both healthy and aphid- infested plants. Important changes in the emitted terpene pattern by the Myzus persicae infested host plant were observed. Using Solid Phase MicroExtraction （SPME） and GC-MS, the （E）-fl-farnesene （EBF） appeared to be emitted by aphid-infested potato and not by healthy plants. To assess the infochemical role of these volatile releases after aphid damage on the aphidophagous predators Episyrphus balteams, the hoverfly foraging behavior was assessed using the Observer 5.0 software （Noldus, Wageningen, The Netherlands）. Aphidfree potato plants were also used as a control volatile source in the predator behavioral study. While aphid-infested plants induced efficient searching and acceptation behaviors leading to egg-laying, no kairomonal effect of healthy potato plants was observed, leading to longer immobility durations and shorter searching periods in the net cage. High oviposition rate of E. balteatus was observed when aphid-infested potato was used （mean of 48.9 eggs per laying and per female）. On the other hand, no egg was produced by the hoverfly on healthy aphid-free plants. The E. balteatus foraging and reproductive behaviors according to the volatile emission from aphid-infested plants are discussed in relation to the potential use of active infochemical molecules in integrated aphid pest management.展开更多
文摘Pillared clay (PILC) was prepared from Moroccan clay and characterized, and its aqueous thymol adsorption capacities were studied using a batch equilibrium technique. So, we tested the encapsulation of thymol by aluminum pillared clay (PILC). The PILCs displayed a total surface area of 270 m2/g, a total pore volume of 0.246 cm3/g and an average pore diameter of 8.9 A, which corresponds to the size of Al13 forming the pillars between the clay layers. The adsorption capacity shown by the PILCs for thymol from water is close to 319 mg?g-1 for low solid/liquid ratio (0.2%). This result suggests that the PILCs have both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PILCs. The experimental data were analyzed by the Freundlich and the Langmuir isotherm types for low values of equilibrium concentration. The rise of the isotherm in this range of concentrations was related to the affinity of thymol for clay sites, and the equilibrium data fitted well with the Freundlich model with maximum adsorption capacity of 319.51 mg/g for a ratio RS/L = 0.2%. Pseudo-first and pseudo-second-order kinetic models were tested with the experimental data and pseudo-first order kinetics was the best for the adsorption of thymol with coefficients of correlation R2 ≥0.986, and the adsorption was rapid with 90% of the thymol adsorbed within the first 20 min.
文摘The high-water content of tomato predisposes it to spoilage by microorganisms and led producers to carry out traditional processing of tomatoes in the form of pasteurized tomato puree. However, rapid acidification of these traditional tomato purees is often observed. Then, the aim of this study was to evaluate the efficacy of the essential oil extracted from Clove (Syzygium aromaticum L.) in the improvement of traditional tomato puree producing technology. Essential oil of Clove (Syzygium aromaticum L.) was extracted by hydrodistillation and its chemical composition was determined by GC and GC/MS. Different types of traditional tomato puree were produced by the modification of the traditional processing technology and the addition of the essential oil introduction step, followed by manual stirring during the process. Based on previous studies, two different essential oil concentrations (5.0 and 7.5 μL∙g−1) were investigated. Physicochemical, microbiological and nutritional analyzes were performed in order to evaluate the quality of the traditional tomato puree produced. Results obtained revealed that the essential oil of Syzygium aromaticum investigated has a chemical composition characterized by the presence of eugenol (59.11%) and eugenol acetate (33.73%). Good stabilization of the physicochemical, microbiological and nutritional parameters in traditional tomato puree samples preserved with essential oil of Syzygium aromaticum were observed when compared to control. The essential oil of Clove, with his biological property, offers a novel approach to the management of traditional tomato puree during storage.
文摘To cope with pathogen and insect attacks, plants develop different mechanisms of defence, in both direct （physical and chemical） and indirect ways （attractive volatiles to entomophagous beneficials）. Plants are then able to express traits that facilitate ＂top-down＂ control of pests by attracting herbivore predators. Here we investigate the indirect defence mechanism of potato plants by analyzing the volatile patterns of both healthy and aphid- infested plants. Important changes in the emitted terpene pattern by the Myzus persicae infested host plant were observed. Using Solid Phase MicroExtraction （SPME） and GC-MS, the （E）-fl-farnesene （EBF） appeared to be emitted by aphid-infested potato and not by healthy plants. To assess the infochemical role of these volatile releases after aphid damage on the aphidophagous predators Episyrphus balteams, the hoverfly foraging behavior was assessed using the Observer 5.0 software （Noldus, Wageningen, The Netherlands）. Aphidfree potato plants were also used as a control volatile source in the predator behavioral study. While aphid-infested plants induced efficient searching and acceptation behaviors leading to egg-laying, no kairomonal effect of healthy potato plants was observed, leading to longer immobility durations and shorter searching periods in the net cage. High oviposition rate of E. balteatus was observed when aphid-infested potato was used （mean of 48.9 eggs per laying and per female）. On the other hand, no egg was produced by the hoverfly on healthy aphid-free plants. The E. balteatus foraging and reproductive behaviors according to the volatile emission from aphid-infested plants are discussed in relation to the potential use of active infochemical molecules in integrated aphid pest management.
