Membrane aroma recovery

By use of selective membranes, water can be removed by filtration from the juice in order to effect its concentration. Depending upon the molecular size of the compounds and the cut-off value of the membrane used, there is likely to be some loss of flavour components. These may be recovered from the permeate by distillation and returned to the juice concentrate. Concentration by these methods is less effective in terms of folding than other methods but can provide advantages in specific cases for example, capital costs associated with hyperfiltration are around 10-30% less than for evaporative systems with aroma recovery equipment. 

Pervaporation have been considered an interesting alternative process for the current industrial options for aroma recovery, distillation, partial condensation, solvent extraction, adsorption, or a combination thereof. It is considered a basic unit operation with significant potential for the solution of various environmental and energetic processes (moderate temperatures). This separation process is based on a selective transport through a dense membrane (polymeric or ceramic) associated with a recovery of the permeate from the vapour phase. A feed liquid mixture contacts one side of a membrane the permeate is removed as a vapour from the other side. Transport through... 

Assis et al. (2005) extracted and concentrated the volatile compounds of the coffee beverage via PV using a flat membrane of ethylene propylene diene terpolymer (EPDM). Shepherd et al. (2002) used PDMS hfs for orange juice aroma recovery. Zhang et al. (2006) used CA membranes for PV separation of a methanol-Cs mixture. 

Fig. 23.4 Organophilic pervaporation (PV) for in situ recovery of volatile flavour compounds from bioreactors. The principle of PV can be viewed as a vacuum distillation across a polymeric barrier (membrane) dividing the liquid feed phase from the gaseous permeate phase. A highly aroma enriched permeate is recovered by freezing the target compounds out of the gas stream. As a typical silicone membrane, an asymmetric poly(octylsiloxane) (POMS) membrane is exemplarily depicted. Here, the selective barrier is a thin POMS layer on a polypropylene (PP)/poly(ether imide) (PEI) support material. Several investigations of PV for the recovery of different microbially produced flavours, e.g. 2-phenylethanol [119], benzaldehyde [264], 6-pentyl-a-pyrone [239], acetone/buta-nol/ethanol [265] and citronellol/geraniol/short-chain esters [266], have been published...

Pierre, F.X., Souchon, I. and Marin, M. (2001) Recovery of sulfur aroma compounds using membrane-based solvent-extraction. Journal of Membrane Science, 187, 239. 

Souchon, I., Afhes, V., Pierre, F.X. and Marin, M. (2004) Liquid-liquid extraction and air stripping in membrane contactor application to aroma compounds recovery. Desalination, 163, 39. 

Processes for production of ethanol and acetone-butanol-ethanol mixture from fermentation products in membrane contactor devices were presented in Refs. [88,89]. Recovery of butanol from fermentation was reported in Ref. [90]. Use of composite membrane in a membrane reactor to separate and recover valuable biotechnology products was discussed in Refs. [91,92]. A case study on using membrane contactor modules to extract small molecular weight compounds of interest to pharmaceutical industry was shown in Ref. [93]. Extraction of protein and separation of racemic protein mixtures were discussed in Refs. [94,95]. Extractions of ethanol and lactic acid by membrane solvent extraction are reported in Refs. [96,97]. A membrane-based solvent extraction and stripping process was discussed in Ref. [98] for recovery of Phenylalanine. Extraction of aroma compounds from aqueous feed solutions into sunflower oil was investigated in Ref. [99]. 

Organic-water mixture Membrane made of elastomeric or hydrophobic polymeric material Modeling studies and application aroma compound recovery [114]... 

Generally, alcohols showed higher separation factors when present in model multicomponent solutions than in binary systems with water. On the other hand, aldehydes showed an opposite trend. The acmal tea aroma mixmre showed a rather different behavior from the model aroma mixmre, probably because of the presence of very large numbers of unknown compounds. Overall, the PDMS membrane with vinyl end groups used by Kanani et al. [20] showed higher separation factors and fluxes for most of the aroma compounds. Pervaporation was found to be an attractive technology. However, as mentioned above the varying selectivities for the different aroma compounds alter the sensory prohle and therefore application of PV for recovery of such mixmres needs careful consideration on a case-by-case basis. 

Pereira CC, Rufino JRM, Habert AC, Noberga R, Cabral LMC, and Borges CP. Aroma compounds recovery of tropical fruit juice by pervaporation Membrane material selection and process evaluation. J. Food Eng. 2005 66(l) 77-87. 

Bagger-Jorgensen, R., et al. Recovery of volatile aroma compounds from black currant juice by vacuum membrane distillation, J. Food Eng., 64, 23, 2004. 

Viladomat FG, Souchon I, Pierre F-X, Marin M. Liquid-liquid and liquid-gas extraction of aroma compounds with hollow fibers. AIChE J 2006 52 2079-2088. Lazarova Z, Boyadzhiev L. Liquid film pertraction—A liquid membrane method for recovery and preconcentration of aromatic amines from their dilute aqueous solutions. Int J Environ Anal Chem 1992 46 233-244. 

Membrane-based separation processes are recognized as environmentally friendly alternatives to conventional separation techniques such as distillation or extraction. The field of large-scale applications covers the range of drinking water processing, potable water production, waste-water treatment, application in the food and pharmaceutical industries, recovery of aroma and active substances as well as sterile filtration of pharmaceuticals and clarification of beverages. 

Raisi A, Aroujalian A. 2011. Aroma compound recovery by hydrophobic pervaporation The effect of membrane thickness and coupling phenomena. Sep. Purif. Technol. 82 53-62. 

Ortiz I. 2008. Recovery of key components of bilberry aroma using a commercial pervaporation membrane. Desalination 224 34-39. 

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