CABRAL, L. M. C.

COUTO, D.

DIJOUX, D.

DORNIER, M.

FREITAS, S.

PALLET, D.

REYNES, M.

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Evaluation of nanofiltration membranes for retention of anthocyanins present in açaí (Euterpe oleracea Mart.) juice.

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V 11th Ibero-American Conference onMembrane Science and TechnologyApril 11 - 14, 2010Sintra, PortugalISBN 978-972-8893-23-1CITEM 2010 - Vllth Ibero-American Conference on Membrane Science and TechnologyBook of AbstractsDeposito Legal 308593/10Published by:Faculdade de Ciencias e TecnologiaUniversidade Nova de LisboaCampus de Caparica2829-516 Caparica, PortugalTel: +351 21 2948300Fax: +351 21 2948550031- EVALUATION OF NANOFILTRATION MEMBRANES FOR RETENTION OFANTHOCYANINS PRESENT IN A<;Af (EUTERPE OLERACEA MART.) JUICED. Coutoa, M. Dornierb, D. Palletb, M. Reynesb, D. Dijouxb, S. FreitasC and L.M.C. Cabrald.*aFederal Rural University of Rio de Janeiro, 23890-000, Seropedica, RJ, Brazilb Centre de Cooperation Internationale en Recherche Agronomique pour Ie Oeveloppement, Montpellier, Cedex 5, FranceCFederal University of Rio de Janeiro,Rio de Janeiro, RJ, Brazild Embrapa Food Technology, 23020-470, Rio de Janeiro, RJ, Brazil*lcabral@ctaa.embrapa.brINTRODUCTION: A~ai is an Amazonian palm. Its berries are harvested as food and it can be described asone of the most important plant species as these fruits make up the major component of the Amazonian peoplediet so that it is very economically and social valuable in this region. The a~ai juice and pulp of a~ai are usedin various juice blends, sodas, and other beverages. In Amazonian region, a~ai pulp is traditionally served withcassava flour or fish but, depending on the local preference, it can be consumed either salty or sweet. A~aiexhibits significantly high antioxidant capacity and therefore, it may have possible health benefits. It is rich inanthocyanins that are natural pigments, water soluble, intensely colored and widely distributed in nature that isfound mainly in fruits and leaves, belonging to the family of flavonoids (BRITO et ai, 2007). They representtogether with the carotenoids the largest class of colored substances in the plant kingdom (GONNET, 1998)and they are responsible for the color of a~ai. Membrane separation processes have the ability to separate andconcentrate bioactive compounds that can therefore be used as ingredients in food, cosmetic and pharmaceuticalindustries (MULDER, 2006).MATERIALS AND METHODS: The raw material for the nanofiltration process was clarified a~ai juice.The pulp was microfiltrated in a 0.2 J.1.m pore size tubular ceramic membrane with total permeation area of0.022 m2 at 2 bar and 35°C ± 2°C. Nanofiltration was carried out in a plate and frame system with 150cm2 of total permeation area. Six membranes were evaluated: (i) NF270 (Dow/Filmtec, composite polyamidepolysulphone membrane, 99% MgS04 nominal rejection), (ii) UTC 60 (Toray, aromatic polyamide, 55% NaCIrejection at 15 bar and 25°C), (iii) MPF 36 (Koch membrane systems, 1 kDa cut off), (iv and v) DK andDL (GE Osmonics, composite membranes, 98% MgS04 and 96% MgS04 rejection at 25°(, respectively)and (iv) NP010 (Microdyn Nadir, polietersulfone composite membrane, 1 kDa cut off). Before starting thejuice nanofiltration, the membrane was conditioned with distilled water for one hour at 35°C and 20 bar. Theexperiments were carried out with no concentration of the product, that means that the permeate and retentatefractions were returned back to the feed tank, at 10, 15, 20 and 30 bar of transmembrane pressure and at 35°C.After the process, the juice inside the nanofiltration system was washed out and the equipment was rinsed toremove the remaining product. Before the evaluation of the water permeability the permeate flux was measuredin order to determine how much the a~ai juice processing reduced the filtration efficiency of the membrane(F%).F(O/) = PWFb - PWFax 10010 PWFbPWFb represents the water flux before processing and PWFa represents the water flux just after processingwithout cleaning. For each process three liters of juice were used. At each 10-minute process, the permeateflux was determined in triplicate. It was made a repeatability test (three assays) with the membrane that shownthe highest permeate flux and higher retention of anthocyanins. To check any possible permeation of antho-cyanin through the membrane, samples of permeate were collected after the application of each transmembranepressure to anthocyanins analysis by the pH differential method (FULEKI, FRANCIS, 1968). The result wasexpressedas cyanidin-3-glucoside. The rejection coefficient of the membrane to anthocyanin was calculated bythe equation:R(%) = (\~ ~;) x 100Cp represents the concentration of anthocyanin at the permeate fraction and Cr the concentration of thiscompound at the feed.RESULTS: The water permeability results showed that there was a linear increase ofthe permeate flux when theapplied transmembrane was increased. NF270 membrane presented the higher permeate flux, 168 L/hm2, 244L/hm2, 312 L/hm2, 428 L/hm2, at 10, 15, 20 and 30 bar respectively, with an average flux 30% higher than theflux of NPOlO, second higher permeate flux. MPF 36 showed the lowest permeate flux, 37 L/hm2, 53 L/hm2,69 L/hm2 and 106 L/hm2 at 10, 15, 20 and 30 bar, respectively. Regarding the juice permeation, NF270membrane showed the highest flux in all pressure ranges, 67 L/hm2 to 10 bar, 84 L/hm2 15 bar, 93 L/hm2 20bar and 102 L/hm2 to 30 bar. Samples of permeate showed 100 retention to anthocyanins. The membraneMPF 36 had the lowest permeability, 8 L/hm2 at 10 bar, 12 L/hm2 at 15 bar, 17 L/hm2 at 20 bar, 27 L/hm2at 30 bar, with anthocyanin concentration in the permeate of 4.5 mg/L at 10 bar. NP010 membrane had apermeate flux higher than the MPF36, however there was a higher permeation of anthocyanins to the permeatestream, 27mg/L at 10 bar. Regarding the retention coefficient it was verified that the membrane MPF36 had99.6% and 99.8% for 10 bar and 15 bar, respectively and NP010 presented 97.7%, 98.5%, 99.1% and 99.7%for 10, 15, 20 and 30 bar, respectively. For all other membranes it was not observed anthocyanin presence inthe permeate fractions. By increasing transmembrane pressure the retention coefficient also increased. Thiscan be explained by the solute adsorption in the membrane pores and surface. When the adsorption occursinside the pores more severe changes occur in both membrane permeate flux and selectivity. After the foulingevaluation it was observed a reduction in the permeate flux with the NF270 membrane with higher permeateflux and a reduction in efficiency of 28% at all range of the evaluated transmembrane pressure. The membraneMPF36 also hadthe lowest permeate flux with reduced efficiency of 49%, 42%, 38% and 38% at 10, 15, 20 and30 bar. The membrane NPOlO had the second performance regarding the permeate flux but had an efficiencyreduction of 70% at all applied transmembrane pressures.CONCLUSION: This work suggests that the nanofiltration process is able to retain anthocyanins of a<;:aisothat it can be used for concentrate this substance. The NF270 membrane presented the highest permeate fluxand the best relationship between permeate flux and anthocyanin retention coefficient.[1] J. F. GONNET, Colour effects of co-pigmentation of anthocyanins revisited. 1: A colorimetric definitionusing the CIELAB scale, Food Chem. 63 (1998) 409-415.[2] EDY S. BRITO; MANUELA c.P. ARAUJO; RICARDO E. ALVES; C. CARKEET; B.A. CLEVIDENCE; J.A. NOVOTNY. Anthocyanins Present in Selected Tropical Fruits: Acerola, Jambolao, Jussara, and Guajiru. J.Agric. Food Chem. 55 (2007) 9389-9394.[3] MARCEL MULDER. Basic Principles of Membrane Technology S.I .. Kluwer Academic Publishers, Nether-lands (1991).[4] T. FULEKI & F.J.FRANCIS Quantitative methods for anthocyanins - 1. Extraction and determination oftotal anthocyanins in cranberries. Journal of Food Science, 33, (1968), 72 - 77.

Evaluation of nanofiltration membranes for retention of anthocyanins present in açaí (Euterpe oleracea Mart.) juice.

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