NMR spectroscopy and chemometrics to evaluate different processing of coconut water.

NMR and chemometrics was applied to understand the variations in chemical composition of coconut water under different processing. Six processing treatments were applied to coconut water and analyzed: two control (with and without sulphite), and four samples thermally processed at 110°C and 136°C (with and without sulphite). Samples processed at lower temperature and without sulphite presented pink color under storage. According to chemometrics, samples processed at higher temperature exhibited lower levels of glucose and malic acid. Samples with sulphite processed at 136°C presented lower amount of sucrose, suggesting the degradation of the carbohydrates after harshest thermal treatment. Samples with sulphite and processed at lower temperature showed higher concentration of ethanol. However, no significant changes were verified in coconut water composition as a whole. Sulphite addition and the temperature processing to 136°C were effective to prevent the pinking and to maintain the levels of main organic compounds.

Chemical composition of Eucalyptus spp. essential oils and their insecticidal effects on Lutzomyia longipalpis.

The chemical composition of essential oils from three species of plants belonging to the Eucalyptus genus was determined and, their insecticidal effects on egg, larva and adult phases of Lutzomyia longipalpis were assessed. The insects were collected in the municipality of Sobral in the State of Ceará, Brazil. Five treatments with different concentrations were performed along with two negative controls, distilled water and Tween 80 (3%), and a positive control, cypermethrin (0.196mg/ml). The tests were carried out in plastic pots internally coated with sterile plaster and filled with a substrate made of rabbit feces and crushed cassava leaves. The eggs, larvae and adults were sprayed with the oils. The hatched larvae were counted for 10 consecutive days and observed until pupation. Insect mortality was observed after 24, 48 and 72h. E. staigeriana oil was the most effective on all three phases of the insect, followed by E. citriodora and E. globulus oils, respectively. The major constituents of the oils were Z-citral and alpha-citral (E. staigeriana), citronellal (E. citriodora) and 1,8-cineole (E. globulus). The Eucalyptus essential oils constitute alternative natural products for the control of L. longipalpis since the median effective concentration (EC(50)) values revealed relevant action as compared with other natural products, some of their chemical constituents are already known for their insecticidal activity and these oils are produced in commercial scale in Brazil.

Adsorptive separation of fructose and glucose from an agroindustrial waste of cashew industry.

Nearly all agroindustrial wastes have appreciable sugar content including cashew apples (Anacardium occidentale, L.), which are an important sub-utilized biomass source in Northeastern Brazil. Adsorption in fixed bed, both in batch and continuous modes, is a low-cost separation technique, which has been widely used in the concentration, separation and purification of bioproducts, such as sugars. The present work is an experimental study aimed at measuring responses in fixed bed, needed for design purposes. Two commercial ion-exchange resins were studied: DOWEX Monosphere 99/Ca and DIAION UBK555. The adsorbents showed linear isotherms for both sugars with marked selectivity for fructose (2.2 for DOWEX and 1.5 for DIAION). A mathematical model was used to estimate kinetic parameters and predict breakthrough behaviour of binary solutions and complex feeds. The kinetics of mass transfer was well described by a linear driving force approximation (LDF) and estimated kinetic constants were around 1 min(-1). The results indicate that the use of independent experiments with synthetic monocomponent solutions leads to reliable parameters, and the model is capable to foresee reasonably well the breakthrough curve of the sugars present in the juice, under different purification conditions. The use of complex feeds led to overshoot behaviour, possibly due to the irreversible adsorption of oligosaccharides.