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a b s t r a c tThis work evaluated the microfiltration process for the clarification of passion fruit juice. Moreover, the influence of some pretreatments (centrifugation, enzymatic liquefaction and chitosan coagulation) before passion fruit juice microfiltration was analyzed. Enzymatic treatment reduced the juice viscosity, and centrifugation step was important for colour and turbidity reductions. Chitosan addition was the most promising pretreatment, since it provides the highest reductions of colour and turbidity, enabling the highest permeate flux in the microfiltration process of pretreated passion fruit juice. The microfiltration process with hollow fibre membranes resulted in a clean passion fruit juice, almost free of turbidity. The applied pretreatment did not influence the characteristics of the obtained permeate. According to the obtained results, the predominant fouling mechanism depends on the applied pretreatment. In centrifuged and enzymatic treated samples, cake formation was found to be the major fouling factor, while internal pore blocking occurred during the filtration of the chitosan pretreated sample.

Poly(lactic acid) (PLA) hollow‐fiber (HF) membranes were prepared by wet spinning with a phase‐inversion technique. Dimethyl sulfoxide (DMSO), N‐methyl‐2‐pyrrolidone (NMP), and 1,4‐dioxane (DIO) were applied as solvents (Ss), and water was applied as a nonsolvent in the precipitation bath. The polymer solution viscosities, PLA–S–water miscibility regions, and precipitation onsets were measured and related to the Hansen solubility and Flory–Huggins interaction parameters. We observed a morphological transition from fingerlike to spongelike pores when DIO was applied as the S instead NMP or DMSO. The water permeabilities of these membranes were not detectable at a transmembrane pressure of 1 bar, and higher pressures caused them mechanical damage. However, the addition of 5 wt % poly(vinyl pyrrolidone) (PVP) induced a higher porosity and water permeabilties from 3.14 to 9.38 L m−2 h−1 bar−1. These membranes were characterized by dialysis, and after 6 h, feed concentration reductions of 2% and 17% for bovine serum albumin and lysozyme, respectively, were observed. In vitro degradation tests showed that a 30% mass loss took place after 90 days of incubation, and a faster initial degradation of spongelike membranes occurred. The spongelike membranes presented a higher maximum stress (12.80 MPa) than the fingerlike membranes (∼6 MPa). With PVP addition, the HFs were less resistant to axial traction and showed a decreased elongation of break from 58% to 23%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45494.

Recebido em 16/1/13; aceito em 8/5/13; publicado na web em 10/6/13 PRODUCTION OF CONCENTRATED FATTY ACIDS BY HYDROLYSIS OF VEGETABLE OILS CATALYZED BY PLANT LIPASE. The aim of this work was to verify the ability of enzymatic crude extract from dormant castor bean seeds to yield concentrated fatty acids by hydrolysis of polyunsaturated vegetable oils such as corn and sunflower. The enzymatic extract exhibited higher activity towards corn oil, which was selected for further studies to determine optimum hydrolysis conditions by factorial design. Maximum hydrolysis percentage (≈84%) was reached at 60% wt. oil:buffer acetate 100 mM pH 4.5, 33 °C and 5.0% wt. of crude extract after 70 min of reaction. These results suggest that the use of low-cost lipase from castor bean seeds has potential for oil hydrolysis.Keywords: oil hydrolysis; factorial design; plant lipase. [1][2][3] Estes números referem-se apenas à produção dos principais óleos e gorduras como soja, algodão, amendoim, girassol, colza, gergelim, milho, oliva, palma, coco, linhaça e mamona, e as gorduras de fonte animal como manteiga, sebo e peixe. 3 A modificação química destes óleos e gorduras mediada por catalisadores químicos é normalmente realizada em elevadas temperaturas e pressão (250 °C e 50 atm). Geralmente, estes processos fornecem produtos de composição química mista e/ou contaminada devido à ocorrência de reações indesejáveis como oxidação, desidratação e interesterificação que requerem etapas posteriores de purificação. Neste contexto, a modificação de óleos e gorduras catalisada por lipases vem se apresentando como uma alternativa atrativa para a indústria, principalmente quando são consideradas algumas das vantagens desta rota como maior rendimento do processo, menor consumo de energia, redução do teor de resíduos e introdução de rotas mais acessíveis de produção. [4][5][6][7][8][9][10] Lipases (glicerol éster hidrolases -E.C. 3.1.1.3) são enzimas que catalisam a hidrólise de ligações éster de óleos e gorduras com diferentes especificidades e podem, em meio orgânico, catalisar uma variedade de reações, como esterificação, interesterificação, transesterificação e aminólise. As lipases têm sido amplamente empregadas na produção de fármacos, emulsificantes, alimentos, perfumaria, diagnósticos médicos, compostos opticamente ativos, polímeros, aromas e fragrâncias, modificações de lipídeos para a produção de biodiesel e lipídeos estruturados e no pré-tratamento de efluentes com elevado teor de lipídeos gerados pelas indústrias de alimentos. [11][12][13][14][15] Essas enzimas encontram-se largamente distribuídas na natureza em tecidos animais e vegetais e biomassa microbiana. [11][12][13][14][15][16] Dentre elas, as lipases microbianas são as mais utilizadas industrialmente. 6,12,13 Por outro lado, as lipases vegetais apresentam algumas vantagens em relação às lipases microbianas e animais como ampla disponibilidade, baixo custo e elevada especificidade. 14-16 As principais fontes de lipases vegetais são o látex de frutos do gênero Carica como baba...