Sugarcane juice with passion fruit pulp was clarified using microfiltration under different T (temperature), P (pressure), and V (tangential velocity). The effects of these processing parameters were evaluated applying a rotational central composite experimental design (RCCD) and response surface methodology (RSM). The tests were performed at a filtration pilot plant using a polyamide hollow-fiber membrane with an average pore diameter of 0.4 µm and filtration area of 0.723 m². In addition, the resistances to the permeate flux during the microfiltration were investigated according to the series resistance. The final permeate flux ranged from 7.05 to 17.84 L·h- 1·m- 2. There was a rapid decline in flux (50%) in the initial stages of microfiltration. T and V were the major variables responsible for the flux increase. The concentration polarization showed the greatest influence on the flux decline, and highest values for the flux decline rate (λ) were found when low pressures were used. In the clarified juice there was a reduction in the contents of total solids, proteins, vitamin C, and acidity, while the soluble solids, pH, and ash contents did not change. Finally, membrane process could produce high quality filtered sugarcane juice with substantial flux and increased luminosity improving organoleptical properties.

A própolis é um produto natural de interesse devido às suas importantes características funcionais. A nanofiltração foi testada para a concentração do extrato proveniente da própolis verde, partindo-se de extratos alcoólico e aquoso. Foi utilizada uma membrana em módulo espiral, de massa molar de corte média entre 150 e 300 g.mol-1. Avaliou-se a influência da variação de pressão, temperatura e velocidade tangencial no fluxo de permeado, e a ocorrência de histerese na membrana. Obteve-se fluxo médio de permeado de 12,0 L/h.m² para a solução alcoólica e de 25,0 L/h.m² para a aquosa. A pressão foi acrescida gradativamente de 2,0 a 5,0 bar, proporcionando variação diretamente proporcional no fluxo de permeado e também no fouling, chegando a 32% em 5,0 bar. O fluxo de permeado foi diretamente proporcional ao aumento da temperatura e da velocidade tangencial. A histerese foi medida a 30 e 40 ºC, demonstrando a característica elástica e reversível da membrana. A eficiência do processo foi medida através das taxas de retenção de flavonoides e compostos fenólicos, obtendo-se retenção de flavonoides de aproximadamente 99% para a solução aquosa e 90% para a solução alcoólica e de compostos fenólicos de cerca de 80 e 24% para soluções aquosa e alcoólica, respectivamente.

Propolis is a natural product with great appeal to consumers and researchers due to its important functional properties. Nanofiltration was tested to concentrate the extract derived from propolis produced by Brazilian bees using a water- and an alcohol-based extract. A spiral membrane module with average molar mass cut-off around 150 to 300 g.mol-1 was used. The influence of pressure, temperature and tangential velocity on the permeate flux was evaluated and hysteresis in the membrane was analyzed. An average permeate flux around 12.0 L/h.m² was obtained for the alcoholic solution and 25.0 L/h.m² for the aqueous solution. The pressure was varied from 2 to 5.0 bar, providing variation directly proportional to the increase of permeate flux, and also to the increase of fouling, which reached 32% at 5.0 bar. The permeate flux also was directly proportional to the increase in temperature and tangential flow. Hysteresis was measured at 30 and 40 ºC and demonstrated the elastic and reversible characteristic of the membrane. The process efficiency was measured by retention index of flavonoids and phenolic compounds. Around 99% of flavonoids in aqueous solution and 90% in ethanol solution were retained, and in the phenolic compounds, around 80 and 24% for the aqueous and the ethanol solutions respectively were retained.