Efecto de la temperatura de refinación química y física de aceites de salvado de arroz sobre el contenido de tocoferoles

The stability of α-, (β+γ)- and δ-tocopherols present in rice bran oil at different heating temperatures has been evaluated. For this purpose, samples of rice bran oil from chemical and physical refining processes in Brazilian industries were studied. The oils were submitted to cabinet drying without air circulation in the absence of light at 100 ºC, 140 ºC and 180 ºC. The samples were taken before heating and after 48, 144, 240, 336, 432, 576, 768, 1008 and 1368h of heating. The analyses of tocopherols were made by high performance liquid chromatography, with a fluorescence detector. It was determined that α-tocopherol was the compound with the fastest degradation rate at the three heating temperatures. The highest degradation rate of tocopherols in both oils occurred at 180 ºC. Among the tocopherols studied, α tocopherol presented the lowest stability, followed by (β+γ)- and δ-tocopherols.La estabilidad de los tocoferoles α-, (β + γ) - y δ presentes en los aceites de salvado de arroz a diferentes temperaturas de calentamiento fueron evaluadas. Para ello, se utilizaron muestras de aceite de salvado de arroz proveniente de los procesos de refinación química y física de industrias brasileñas. Los aceites fueron sometidos a 100 ºC, 140 ºC y 180 ºC, en cabinas de secado sin circulación de aire, bajo ausencia de luz. Las muestras fueron tomadas antes de la calefacción y después de 48, 144, 240, 336, 432, 576, 768, 1008 y 1368 h de calentamiento. El análisis de tocoferoles fue realizado por cromatografía líquida de alta eficacia, con detector de fluorescencia. Se observó que el α-tocoferol fue el compuesto con degradación más rápida en las tres temperaturas de calentamiento. La mayor tasa de degradación de los tocoferoles, en ambos aceites, ocurrió a la temperatura de 180 ºC. Entre los tocoferoles analizados, α-tocoferol presentó menor estabilidad, seguido por los (β + γ) - y δ-tocoferoles

Perfil de ácidos graxos do óleo de semente de abóboras crioulas (Cucurbita máxima L.).

Trabalho publicado no III Congresso Brasileiro de Processamento de Frutas e Hortaliças, 2013

Effect of nanoencapsulation using PLGA on antioxidant and antimicrobial activities of guabiroba fruit phenolic extract.

Guabiroba fruit has been highlighted for its high phytochemical content, particularly of phenolic compounds. The stability, bioavailability, and bioactivity of these compounds can be enhanced by nanoencapsulation, to improve functionality. Poly (D,L-lactic-co-glycolic) acid (PLGA) nanoparticles containing phenolic extract of guabiroba (GPE) were synthesized by an adapted emulsion-evaporation method and their physico-chemical and functional properties were studied at two lactic to glycolic acid ratios (50:50 and 65:35). Higher (P < 0.05) or equivalent antioxidant capacity compared to free GPE were observed for GPE-loaded nanoparticles. Free extract and PLGA nanoparticles were effective inhibitors of Listeria innocua, with lower (P < 0.05) GPE concentrations required for inhibition when nanoencapsulated. Also, reduction of ROS generation in non-cancer cells was achieved with lower GPE concentrations (P < 0.05) after encapsulation. These results suggest that PLGA nanoparticles can be used as a delivery system for phenolic compounds at lower levels than originally required for enhanced functional properties

Pregelatinized rice bran flour as stabilizer for guava nectar.

Rice bran flour is a byproduct of rice processing and can be used as food. The objective of the current study was to use pregelatinized rice bran flour along with hydrocolloids to stabilize guava nectar, as well as to evaluate the stability of bioactive compounds during a storage period of 180 days. For this purpose, the guava fruits were processed in the form of pulp, following the elaboration of the nectars. Four formulations were prepared: one control (pulp, water, and sugar) and three by the addition of xanthan, guar gum, and pregelatinized rice flour. The analyses on guava nectars were performed 24 h after their processing and at every 45-day intervals during the entire 180 days study period. The experiment was done in triplicate and the results were expressed on a wet basis. The physicochemical properties, color, and the bioactive compounds in the guava nectars were influenced mainly in the formulation of pregelatinized rice bran flour & guar gum. The same composition also resulted in greater stability. Despite the absence of considerable differences in the guava nectar formulations for the evaluated parameters, the addition of stabilizers seems to be necessary for a visual quality aspect, since the sedimentation that occurs in this type of nectar depreciates the appearance of this product, thus compromising its competitiveness. The pregelatinized rice bran flour associated with guar gum was found to be the most effective strategy for stabilization of guava nectar, combined with the low cost and ease of obtaining, compared to other hydrocolloids commonly used in the food industry