Aroma recovery by pervaporation

Aroma compounds are a blend of organic and volatile compounds present at very low concentration, usually ppm or ppb levels in many natural sources. Chemically they can be distinguished as esters, alcohols, aldehydes, terpens, amines, mercaptans, lactones etc [1]. They are the main responsible of the fragrance, the taste and the odour of many natural products from which they are usually isolated. Aroma compounds are widely used, for their properties, in the cosmetic and food industry. Above all during some industrial processes for the production of beverages and juices, during the concentration step, the thermal treatment can cause the loss of many of these valuable components. Furthermore, chemical modifications due to thermal degradation, Maillard reactions or oxidation can occur. In order to maintain the original flavour of the product, is important to recover the aroma compounds and add them back to the concentrated juice [2]. Common techniques for aroma recovery are distillation, partial condensation and adsorption. However, some disadvantages are associated to these processes such as degradation of the aroma compounds, high energy consumption and aroma contamination [3]. Pervaporation (PV) can be considered as a valid alternative to other common techniques [4,5]. It allows, in fact, the recovery of volatile compounds at low temperatures, preserving the molecular integrity of the aroma components with a lower energy consumption and higher selectivity. In this study, a model aroma solution from the citron fruit (Citrus medica L. cv Diamante) was studied during PV process by using different types of membranes and the effect of some variables (aroma concentration, temperature) on membrane performances was also evaluated. References [1] A. Aroujalina, A. Raisi, Recovery of volatile aroma components from orange juice by pervaporation, Journ. of Mem. Sci. 303 (2007) 154-161. [2] C. C. Pereira, C. P. Ribeiro Jr., R. Nobrega, C. P. Borges, Pervaporative recovery of volatile organic compounds from fruit juices, Journ. of Mem. Sci. 274 (2006) 1-23. [3] F. Lipnizki, J. Olsson, G. Trägårdh, Scale up of pervaporation for the recovery of natural aroma compounds in the food industry. Part 1: simulation and performance, Journ. of Food Eng. 54 (2002) 183-195. [4] A. Figoli, L. Donato, R. Carnevale, R. Tundis, G.A. Statti, F. Menichini, E. Drioli, Bergamot essential oil extraction by pervaporation, Desalination 193 (2006) 160-165. [5] A. Cassano, A. Figoli, A. Tagarelli, G. Sindona, E. Drioli, Integrated membrane process for the production of highly nutritional kiwifruit juice, desalination 189 (2006) 21.