Neste trabalho foram estudadas as melhores condições para a desidratação osmótica de laranjas, sendo verificadas as alterações nas características físico-químicas da fruta. Um planejamento experimental fatorial 2³ completo foi realizado, analisando-se a influência dos fatores tempo, da concentração da solução e proporção fruta:solução osmótica sobre o ganho de sólidos, a perda de água e redução de massa das laranjas desidratadas osmoticamente. Após desidratação, as frutas foram secas em secador de bandejas até umidade de 20%. Determinaram-se no produto, o pH, a acidez titulável, a vitamina C, os carotenoides, o conteúdo fenólico e a cor. Os melhores resultados de desidratação osmótica foram obtidos utilizando-se uma solução de sacarose de 60 ºBrix, na proporção fruta:solução de 1:3 durante 90 min, que resultou em 3,5 g sólidos100g-1, 10,6 gágua 100g-1 e 7,1 g 100g-1 para ganho de sólidos, perda de água e redução de massa, respectivamente. As perdas de conteúdo fenólico e a atividade antioxidante foram 45,1 e 37,3% menores que na secagem convencional demonstrando a eficiência do processo para preservação das propriedades funcionais do produto.

The best conditions for osmotic dehydration of oranges was studied, assessed by determining the physico-chemical characteristics of the fruit. The study was conducted in 2³ full factorial experimental design to evaluate the influence of time, solution concentration and fruit:solution ratio on the solid gain, water loss and mass reduction of osmotically dehydrated oranges. After dehydration, the fruits were dried in tray dryer until 20% moisture. In the product the pH, titratable acidity, vitamin C, carotenoids, phenols content and color were determined. The best results of osmotic dehydration were obtained using a sucrose solution 60 ºBrix, fruit:solution ratio 1:3 for 90 min, that resulted in 3.5 g solid 100g-1, 10.6 g water 100g-1 and 7.1 g 100g-1 of solid gain, water loss and weight reduction, respectively. The losses of phenolic content and antioxidant activity were 45.1 and 37.3% lower than in conventional drying, demonstrating the efficiency of the process for the preservation of functional properties of the product.

Onion (Allium cepa) is being studied as a potential anticancer agent, but little is known regarding its effect in multidrug resistance (MDR) cells. In this work, the cytotoxicity of crude onion extract (OE) and fractioned extract (aqueous, methanolic and ethyl acetate), as well as some onion compounds (quercetin and propyl disulfide) were evaluated in Lucena MDR human erythroleukemic and its K562 parental cell line. The capacity of OE to induce apoptosis and/or necrosis in these cells, the possible participation of oxidative stress and DNA damage were also assessed. Similar sensitivities were obtained for both tumoral cells, however only OE caused significant effects in the cells. In K562 cells, a significant increase of apoptosis was verified while the Lucena cells experienced a significant increase of necrosis. An antioxidant capacity was verified for OE discarding oxidative damage. However, OE provoked similar significant DNA damage in both cell lines. Thus, the OE capacity to overcome the MDR phenotype suggests anti-MDR action of OE.