Recovery Of Aroma Compounds Research Articles

Recovery of aroma compounds from Zhenjiang aromatic vinegar by supercritical fluid extraction

SummaryZhenjiang aromatic vinegar, which is produced from sticky rice through solid‐state fermentation, is highly prized as one of the four famous China‐style vinegars, owing to its unique flavour. In this study, a method of supercritical fluid extraction (SFE) was used for the first time to recover aroma compounds from Zhenjiang aromatic vinegar. For this purpose, the optimal conditions for the extraction of aroma compounds by SFE were determined as follows: CO2 flow rate, 25 L h−1; extraction time, 2 h; extraction pressure, 35 MPa; and extraction temperature, 323 K. Using headspace solid‐phase microextraction‐gas chromatography–mass spectrometry (HS‐SPME‐GC‐MS) analysis, a total of 49 and 44 aroma compounds were identified in Zhenjiang aromatic vinegar and its SFE extract, respectively. Acetic acid, ethyl acetate, furfural, phenethyl alcohol, tetramethyl‐pyrazine, 3‐hydroxybutanone and benzaldehyde were the main aroma compounds in the vinegar and its SFE extract. SFE is a fast and sensitive method to recovery aroma compounds from the vinegar.

Recovery of volatile fruit juice aroma compounds by membrane technology: Sweeping gas versus vacuum membrane distillation

The influence of temperature (10–45 °C), feed flow rate (300–500 L/h) and sweeping gas flow rate (1.2–2 m 3 /h) on the recovery of berry fruit juice aroma compounds by sweeping gas membrane distillation (SGMD) was examined on an aroma model solution and on black currant juice in a lab scale membrane distillation set up. The data were compared to recovery of the aroma compounds by vacuum membrane distillation (VMD). The flux of SGMD increased with an increase in temperature, feed flow rate or sweeping gas flow rate. Increased temperature and feed flow rate also increased the concentration factors ( C permeate / C feed ) of the aroma compounds. At 45 °C the most volatile and hydrophobic aroma compounds obtained the highest concentration factors: 12.1–9.3 (black currant juice) and 17.2–12.8 (model solution). With black currant juice a volume reduction of 13.7% (vol.%) at 45 °C, 400 L/h, resulted in an aroma recovery of 73–84 vol.% for the most volatile compounds. Compared to VMD, the aroma recovery with SGMD was less influenced by the feed flow rate but more influenced by the temperature. Higher fluxes were achieved during concentration by VMD and this reduced the operation time, which in turn reduced the degradation of anthocyanins and polyphenolic compounds in the juice. High temperature evaporation is the most widely used industrial technique for aroma recovery and concentration of juices, but membrane distillation (MD) may provide for gentler aroma stripping and lower energy consumption. This study gives important clues about the fate of berry juice aroma compounds and polyphenols during concentration by MD, and identifies the main factors influencing the aroma recovery efficiency with MD. Both SGMD and VMD are promising techniques for gentle stripping of berry juice aroma compounds and deserve further consideration as alternative techniques for gentle aroma stripping in industrial fruit juice processing. ► Workability of membrane distillation for gentle recovery of fruit juice aroma compounds. ► Effects of flow rates, temperature, and physicochemical properties of compounds. ► Theoretical prediction of aroma recovery versus feed volume reduction. ► Theoretical principles of sweeping gas and vacuum membrane distillation.

Pervaporative aroma compounds recovery from lemon juice using poly(octyl methyl siloxane) membrane

AbstractBACKGROUND: In this research, a pervaporation process was used to recover volatile aroma compounds from lemon juice using a poly(octyl methyl siloxane) membrane. The majority of previous studies have been with binary model feed systems, while the results with actual feed mixtures did not always match those with model feeds. In order to successfully optimize the pervaporation process, it is essential to work with actual fruit juice. The influences of various operating parameters such as feed flow rate, feed temperature and permeate pressure on the permeate flux and selectivity were investigated. For this purpose, three compounds that make a significant contribution to lemon juice aroma, namely, α‐pinene, β‐pinene and limonene were studied.RESULTS: It was shown that decreasing the permeate pressure increased both permeation flux and enrichment factor, while an increase in feed temperature increased the water flux more significantly than the aroma compounds flux, resulting in lower enrichment factor. Also, the results indicated that feed flow rate had no significant effect on the performance of the process.CONCLUSION: The membrane used was found to be very selective towards α‐pinene, β‐pinene and limonene. It can be concluded that pervaporation is an attractive technology for the recovery of lemon aroma compounds as it yields good separation and operates under mild conditions. Copyright © 2010 Society of Chemical Industry

Liquid membrane technology: fundamentals and review of its applications

AbstractOVERVIEW: During the past two decades, liquid membrane technology has grown into an accepted unit operation for a wide variety of separations. The increase in the use of this technology owing to strict environmental regulations and legislation together with the wider acceptance of this technology in preference to conventional separation processes has led to a spectacular advance in membrane development, module configurations, applications, etc.IMPACT: Liquid membrane technology makes it possible to attain high selectivity as well as efficient use of energy and material relative to many other separation systems. However, in spite of the known advantages of liquid membranes, there are very few examples of industrial applications because of the problems associated with the stability of the liquid membrane.APPLICATIONS: Liquid membrane technology has found applications in the fields of chemical and pharmaceutical technology, biotechnology, food processing and environmental engineering. On the other hand, its use in other fields, such as in the case of hydrogen separation, the recovery of aroma compounds from fruits, the application of ionic liquids in the membrane formulation, etc., is increasing rapidly. Copyright © 2009 Society of Chemical Industry

A predictive mass transfer model for aroma compounds recovery by pervaporation

Abstract In this study, a predictive mass transfer model was developed to describe pervaporative separation of pomegranate aroma compounds from multicomponent solutions. The Flory–Huggins theory was used to predict equilibrium sorption of aroma compounds and water into the membrane. The penetrant transport through the membrane was described with the generalized Maxwell–Stefan equations, which are able to account for the bulk flux contribution as well as the diffusive coupling effect. A simple formula for estimating the Maxwell–Stefan diffusion coefficients of aroma compounds through the membrane in multicomponent solutions was utilized based on the free volume theory. The effects of operating parameters such as feed concentration and temperature on the permeation flux and aroma selectivities were investigated via both the model prediction and experiments. A reasonable agreement between predicted and experimental data was observed.

Application of Supercritical Fluid Extraction for the Recovery of Aroma Compounds to be Used in Fast Aged Rum Production

Supercritical CO2 extraction was used for the recovery of valuable aroma components with application in blending steps for fast aged rum processes. Head Alcohol, Crude and Aged Sugar Cane Spirit process streams were used to firstly quantify different concentrated aroma fractions with interest in food applications. Alcohols ratio, esters composition and carboxylic acids concentration criteria were used to determine the quality of extracts. The economical profitability of this technology was especially evident for Head Alcohol and Aged Sugar Cane Spirit extracts, since the most interesting compounds were concentrated more than 300 times compared to commercial aged rum. Additional experiments were performed in the range 8-15 MPa and 313-333 K to obtain empirical correlations to predict solubility data for further scale-up applications.

Extraction of aroma compounds in a HFMC: Dynamic modelling and simulation

In the present work the dynamic behaviour of hollow-fiber membrane contactors (HFMCs) used for the recovery of aroma compounds from an aqueous feed phase with the help of a conventional solvent has been studied. Many aroma compounds play a significant role in the production of flavorants, which are used in the food industry to flavor, improve and increase the appeal of their products. Various aroma compounds with different physico-chemical characteristics have been chosen for this study. A real dynamic model of membrane-based solvent extraction (MBSE) process was developed. In the studied system, the aqueous feed and solvent phases are re-circulated to their respective storage tanks after contacting in a hollow fibres membrane contactor. The developed dynamic model was verified with experimental data from the literature and good level of agreement was found. It has been used as a tool to simulate and conclude about the influence of various module configurations, membrane characteristics and hydrodynamic conditions on the extraction of various aroma compounds. It was noted that transient models of membrane-based separation need attention to improve the simulation studies and experimental validity to encourage it at larger scales.

Multicomponent pervaporation process for volatile aroma compounds recovery from pomegranate juice

The present work describes the possibility of using pervaporation process to recover the pomegranate aroma compounds from an actual pomegranate juice and a model aroma solution. Four different chemicals representing four major kinds of aroma compounds, namely, 3-methyl butanal, isopentyl acetate, n-hexanol and α-ionone, were utilized in this work. Three POMS membranes and two PDMS membranes were tested for pervaporation and compared for their separation performance. The influence of various operating parameters such as feed flow rate, feed temperature and permeate pressure on the permeation flux and aroma compounds enrichment factor was investigated. Feed flow rate was shown to have no significant effect on both total flux and aroma enrichment factor, whereas feed temperature and permeate pressure had highly significant effects. An increase in feed temperature led to higher flux and enrichment factor. As permeate pressure increased, the flux and enrichment factor of some aroma compounds decreased. Some of the aroma compounds showed higher enrichment factor at higher permeate pressures. Finally, the activation energy of permeation and the membrane permeability for each aroma compound were determined.

Modeling and analysis of vacuum membrane distillation for the recovery of volatile aroma compounds from black currant juice

A vacuum membrane distillation (VMD) model has been developed and validated with experimental data. The model consists of an extended transport model for the VMD process and is able to predict the effects of concentration and temperature polarization on the overall process performance. To validate the model, first it was tested with few experimental case studies from literature [S. Bandini, G.G. Sarti, Heat and mass transport resistances in vacuum membrane distillation per drop, AIChE J. 45 (7) (1999) 1422–1433; K.W. Lawson, D.R. Lloyd, Membrane distillation. I. Module design and performance evaluation using vacuum membrane distillation, J. Membr. Sci. 120 (1996) 111–121; A.M. Urtiaga, G. Ruiz, I. Ortiz, Kinetic analysis of the vacuum membrane distillation of chloroform from aqueous solutions, J. Membr. Sci. 165 (2000) 99–110]. Then the VMD model has been validated with experimental data collected from the recovery of aroma compounds from black currant [R.B. Jørgensen, A.S. Meyer, C. Varming, G. Jonsson, Recovery of volatile aroma compounds from black currant juice by vacuum membrane distillation, J. Food Eng. 64 (2004) 23–31]. In this work, recovery of 12 characteristic volatile aroma compounds from black currant juice has been studied. The simulated results from the VMD model, in terms of aroma concentration in the permeate have been compared with those obtained from laboratory experiments. The validated model has been used to study the effects of various process and membrane parameters on the concentration factor. The physical properties of various aroma compounds have been predicted using group contribution method as a function of temperature.

Separation and concentration of bilberry impact aroma compound from dilute model solution by pervaporation

AbstractBACKGROUND: In the present work, the flavor compounds of natural juice of bilberries were qualitatively analyzed by GC‐MS, leading to the identification of trans‐Hex‐2‐en‐1‐ol as one of the major ‘impact aroma’ compounds of this fruit. The pervaporation of trans‐Hex‐2‐en‐1‐ol from diluted aqueous solutions was studied using commercial polydimethylsiloxane (PDMS) capillary membranes. The influences of solvent composition (water/ethanol mixtures), initial concentration of the aroma compound, flow rate and temperature of the feed were studied.RESULTS: High selectivity of the PDMS membrane towards the aroma compound was obtained, leading to enrichment factors in the range 100 < β < 200. Mass transfer resistance was found to be located in the pervaporation membrane. Experimental data showed a linear dependency of the permeation flux of trans‐Hex‐2‐en‐1‐ol on the differences in partial pressures of the compound across the pervaporation membrane. The permeability coefficient of the PDMS membrane to the transport of trans‐Hex‐2‐en‐1‐ol was calculated as Pm, Hex(50 °C) = 7.62 × 10−11 mol m−1 s−1 Pa−1.CONCLUSION: The membrane used was found to be very selective toward trans‐Hex‐2‐en‐1‐ol. A model based on the solution‐diffusion mechanism was applied. The mass transfer parameters needed for the design of a pervaporation process for aroma compound recovery were obtained. Copyright © 2008 Society of Chemical Industry

Recovery of Wine-Must Aroma Compounds by Supercritical CO2

The fractionation of wine musts (the fermentation broth that leads from grape juice to wine) of highly aromatic grape varieties was performed with supercritical carbon dioxide at pressures between 11 and 18 MPa and temperatures between 308 and 318 K. Different configurations of the separation devices were tested after the extraction step to improve the fractionation process. Headspace chromatography and Karl Fisher analyses were used to measure the composition of the extracts. A significant enrichment of the supercritical extracts on aromatic compounds was observed. The recovery of the aromatic compounds from the high pressure solvent stream poses technical problems that must be solved before the process can be feasible in an industrial scale.

Recovery of volatile aroma components from orange juice by pervaporation

Pervaporative recovery of volatile aroma compounds from orange juice was studied to determine the influence of various operating parameters such as feed flow rate which is correspondent with Reynolds numbers of 500, 1000, 1500, 2000, and 2500, feed temperature (25, 40, and 50 °C) and permeate pressure (1, 10, 20, 30, and 40 mmHg) on flux and selectivity. Feed flow rate had not significant effect on performance of process but feed temperature and permeate pressure variations affected the flux and selectivity of aroma compounds. Increasing in feed temperature led to higher flux and enrichment factor. As permeate pressure increased, the flux and enrichment factor of some aroma compounds decreased. Some of the aroma compounds showed higher enrichment factor at higher permeate pressures.

Permselectivity, solubility and diffusivity of propyl propionate/water mixtures in poly(ether block amide) membranes

This work is concerned with the separation of propyl propionate/water mixtures by pervaporation using PEBA membranes, which is relevant to aroma compound recovery from dilute aqueous solutions. The solubility and diffusivity pertinent to the permselectivity were investigated. The effects of feed concentration and the operating temperature on the separation performance were studied. Under the experimental conditions tested, the permeate concentration was much higher than the solubility limit, and upon phase separation substantially pure propyl propionate could be achieved. The diffusivity of propyl propionate through the membrane from its dilute aqueous solutions was affected by the solution concentration exponentially. It was shown that the permselectivity of the membrane for propyl propionate/water separation was mainly derived from its sorption selectivity due to the organophilicity of the membrane. The diffusivity of pure propyl propionate in the membrane was about 28 times higher than pure water diffusivity.

HTPB‐based polyurethaneurea membranes for recovery of aroma compounds from aqueous solution by pervaporation

AbstractHydroxyterminated polybutadiene (HTPB)‐based polyurethaneurea (PU), HTPB‐PU, was synthesized by two‐step polymerization and was firstly used as membrane materials to recover aroma, ethyl acetate (EA), from aqueous solution by pervaporation (PV). The effects of the number–average molecular weight (Mn) of HTPB, EA in feed, operating temperature, and membrane thickness on the PV performance of HTPB‐PU membranes were investigated. The membranes demonstrated high EA permselectivity as well as high EA flux. The DSC result showed two transition temperatures in the HTPB‐PU membrane and contact angle measurements revealed the difference of hydrophobicity of the membrane at both sides, which were induced by glass plate and air, respectively, due to movement of the soft hydrophobic polybutadiene (PB) segments in HTPB‐PU chains. Furthermore, the PV performance of the HTPB‐PU membrane with the hydrophobic surface facing the feed was much better than that with the hydrophilic surface. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 552–559, 2007

Perspectives and limitations of using on-line mass spectrometry for monitoring of pervaporation processes

Organophilic pervaporation has a high potentialfor aroma recovery from dilute aqueous solu-tions because it involves a low energy inputwhen compared with other separation processessuch as distillation; also, it operates at mildconditions allowing for a direct recovery ofaroma compounds from fermentation processesor other complex media.In traditional pervaporation systems, acomplete condensation of permeate occurs in asingle condenser. Aiming to fractionate the per-meate stream, in order to obtain defined aromaprofiles, this study involves the use of a pervapo-ration module followed by two condensers inseries operating at different temperatures, allow-ing for a fractionated condensation. Due to thedifferent relative volatilities of the different com-ponents of the system, an increase on the globalseparation factor may be achieved. This approachrequires an optimisation of the temperature(s) ofcondensation in the downstream circuit. Mass spectrometry (MS) has proved to be apowerful analytical tool with high precision andsensitivity. In this work, we evaluate its domainof applicability as an on-line monitoring toolcoupled with pervaporation (PV). Coupled MS/PVhas a high potential for the understanding of PVsystems because it allows for on-line monitoringof each component of the permeate stream,enabling transient studies and reducing experi-mental workload signific antly when varying anyexperimental parameter.

The influence of process parameters on aroma recovery by hydrophobic pervaporation

Hydrophobic pervaporation has been shown to be a promising, alternative process for the recovery of volatile organic components from their aqueous solutions, such as the recovery of aroma compounds in the food industry. Until now most of the research on the influence of operating parameters on aroma recovery by pervaporation has been conducted on the laboratory scale. The number of studies dealing with the scaling-up of the pervaporation process for the separation of multi-component mixtures is still relatively small, and usually has a number of limitations. The aim of this study was to investigate module design aspects of pervaporation, using a modified version of an existing pervaporation simulation tool for aroma recovery. By applying the simulation to four aroma compounds, two alcohols and two esters, the influence of major process and module design parameters on the performance of a single module has been investigated. The results of the simulation show that detailed modelling of single module behaviour is an important aspect of the optimisation of pervaporation plant performance.

Recovery of strawberry aroma compounds by pervaporation

The main objective of this study was to determine the effects of feed temperature (30, 40, 50 °C), concentration (50, 100, 150 ppm), composition (different strawberry model solutions) and permeate pressure (4, 8 mbar) on recovery of strawberry aroma compounds by pervaporation. Pervaporation was performed using a hydrophobic membrane, PERVAP 1070 (PDMS). As the feed temperature increased or downstream pressure decreased, the mass flux and selectivity increased in pervaporation of methyl butyrate (MTB) aqueous solution. Increase in feed concentration led to higher organic fluxes but lower selectivity in binary aqueous solutions of both MTB and ethyl butyrate (ETB). PERVAP 1070 showed higher selectivity towards MTB than ETB and MTB flux was affected negatively by the presence of ETB in the feed solution. The presence of other aroma compounds adversely affected the selectivities of MTB and ETB.

Pervaporation of Aroma Compounds Using Virgin and Silicalite‐Filled Organophilic Membranes: Effect of Aroma Compound Structure and Comparison with Distillation Selectivity

Pervaporative recovery of individual aroma compounds having different functional groups is studied using polydimethylsiloxane (PDMS) as well as silicalite filled PDMS (PDMS SA‐5) membranes. The aroma compounds studied are linalool, citronellal, menthone, and β‐ionone. The performance of both the membranes was compared. The effective selectivity of organophilic membranes is compared with the vapor–liquid equilibria (VLE) selectivity estimated using thermodynamic data. Effect of the nature of each aroma compound on its pervaporation performance is also discussed. Sorption effect was found to be predominant in determining the pervaporation selectivity.

P(VDF- co-HFP) membrane for recovery of aroma compounds from aqueous solutions by pervaporation : І. Ethyl acetate/water system

In this study, poly(vinylidene fluoride- co-hexafluoropropene) (P(VDF- co-HFP)) was firstly used as a membrane material in organophilic pervporation for aroma compounds’ recovery. Separation and transport properties of P(VDF- co-HFP) coated polypropene (PP) composite membrane in pervaporation of EtAc–water mixture were investigated. The effects of two process conditions (EtAc feed concentration and operating temperature) on pervaporation parameters (permeation flux and separation factor) were discussed in detail. The study shows that acetone-fabricated membranes have excellent mechanical strength, thermal stability and film-forming properties. In addition, they have ideal pervaporation performances compared to commonly used poly(dimethylsixolane) (PDMS) membrane and poly (ether block amide) (PEBA) membrane. Its separation factor is higher than that of PEBA membrane but lower that of PDMS membrane. The permeate flux is relatively high, which depends on not only the nature of the given membrane material but also the membrane-formed special structure and morphology. Mass transports in the membrane were investigated based on the change of microstructure from DSC analysis during the swelling process. The activation energies for permeation of water ( E P,W) and EtAc ( E P,E) calculated from the slopes of Arrhenius plots of ln( J) versus 1/ T were employed to explain the diffusion process. In general, the sorption process dominates the separation mechanism.

Aroma compounds recovery of tropical fruit juice by pervaporation: membrane material selection and process evaluation

In the present work, aroma recovery of tropical fruit juice by pervaporation process was investigated using model solutes and different kinds of composite membranes. As feed solution, binary and quaternary synthetic aqueous solutions were used, as well as the single strength and the clarified pineapple juices. Composite membranes (flat or hollow fiber), prepared in laboratory or commercial ones, were used for comparison. The water permeability and the overall mass transfer coefficient for each organic solute were determined. The experimental pervaporation results were used as input for a simulation of a permeation unit, allowing a preliminary comparison of the different membranes investigated. Experimental and simulation results indicated that EPDM membranes presented the best performance.