RESUMO
This study evaluated the effect of convective drying on the degradation of color and phenolic compounds of purple basil (Ocimum basilicum L.) leaves, and the hygroscopic behavior of dried leaves. The fresh leaves underwent drying at 40 °C, 50 °C, 60 °C, and 70 °C. Degradation of chlorophyll, flavonoids, and phenolic compounds were evaluated during drying and the hygroscopicity was evaluated through the moisture sorption isotherms. The drying mathematical modeling and the moisture sorption data were performed. The effective diffusivity for the drying increased from 4.93 × 10−10 m2/s at 40 °C to 18.96 × 10−10 m2/s at 70 °C, and the activation energy value (39.30 kJ/mol) showed that the leaves present temperature sensibility. The leaves dried at 40 °C had less degradation of phenolic compounds and color variation, but the drying process was too slow for practical purposes. Modified Page, Diffusion Approximation, and Verna models had excellent accuracy in drying kinetics. The isotherms showed that, in environments with relative humidity above 50%, the purple basil leaves are more susceptible to water gain, and at 8.83 g H2O/100 g db moisture, it guarantees the microbiological stability of the dried leaves. The Oswin model was the most suitable for estimating the moisture sorption isotherms of the dried leaves.
RESUMO
Water-solid interactions were explored in purified and freeze-dried Prosopis alba exudate gum as approach to get a deeper insight of structural and functional aspects of this novel biomaterial. Particularly, the study of water-binding properties combined with glass transition temperatures allowed obtaining interesting theoretical data for practical applications. The Guggenheim-Anderson-de Boer (GAB) and Generalized D'Arcy and Watt (GDW) models were applied to describe the sorption behavior and thermodynamic properties of the studied gum. The study of the relationship between relative humidity, water content and thermal transitions allowed to characterize the material in terms of water plasticizing susceptibility as well as define the suitable storage conditions that guarantee the quality, safety and physical stability of P. alba gum. Obtained results contribute to the characterization of a non-conventional exudate gum with great potential for its use in different food industry applications.
Assuntos
Gomas Vegetais/química , Prosopis/química , Temperatura , Vitrificação , Argentina , Varredura Diferencial de Calorimetria , Exsudatos e Transudatos , Termodinâmica , Água/químicaRESUMO
Cecropia glaziovi Snethl., Urticaceae, is commonly used in South America and is one of the species included in the Brazilian Medicinal Plants Research Program. Pharmacological studies have led to reports of the potential of C. glaziovi as a hypotensive, antiasthmatic and anxiolytic agent. The strict requirements regarding the quality, safety and effectiveness of phytopharmaceutical products represent an enormous challenge in the search for products with a high level of uniformity, reproducibility and stability. The incorporation of dry extracts into multiparticulate dosage forms, such as pellets produced by extrusion/spheronization technology, is a suitable alternative to overcome the lack of technological properties of dry extracts, since they are associated with low flowability and high hygroscopicity. In this study, an optimized dry extract (ODE) of C. glaziovi was incorporated into pellets seeking to decrease the moisture sorption and increase the stability, safety and percentage of the extract in the final product. Pellets containing around 50% of ODE were considered the most technologically viable, offering a narrow particle size distribution, significant improvement in the flowability and compressibility properties, and decrease in the moisture compared with the ODE. In conclusion, pellets containing a high dose of the C. glaviovi extract were successfully prepared, achieving degrees of quality, physical stability and feasibility compatible with the desirable characteristics of a phytopharmaceutical.
RESUMO
Dehydration and rehydration processes of Pleurotus ostreatus fruiting bodies were investigated in this work. Mushroom samples were dehydrated at 40, 50 and 60 ºC, using drying air with relative humidity of 75 percent. The rehydration was investigated at different temperatures of immersion water (25, 55 and 85 ºC) and different immersion times (30, 75 and 120 minutes). The best rehydration occurred for the samples dried at 40 ºC. The rehydration could be done in water at room temperature, during 30 minutes. Water sorption isotherms of samples were determined at 30, 40 and 50 ºC. Both GAB and BET models satisfactorily represented the experimental data of moisture sorption of dried mushrooms.
Processos de desidratação e de rehidratação de cogumelos da espécie Pleurotus ostreatus foram avaliados neste trabalho. Os cogumelos foram desidratados a 40, 50 e 60 ºC, com umidade relativa do ar de 75 por cento. O processo de rehidratação foi avaliado para diferentes temperaturas de água de imersão (25, 55 e 85 ºC) e diferentes tempos de imersão (30, 75 e 120 minutos). A melhor temperatura de secagem foi 40 ºC, levando em consideração a melhor rehidratação dos cogumelos desidratados nesta temperatura. A rehidratação pode ser feita em água a temperatura ambiente, por 30 minutos. Isotermas de sorção de umidade de amostras foram determinadas a 30, 40 e 50 ºC.Tanto o modelo de GAB quanto o de BET representaram satisfatoriamente os dados experimentais de isoterma de sorção de umidade.