Retention Of Aroma Compounds Research Articles

Retention of aroma compounds from Mentha piperita essential oil by cyclodextrins and crosslinked cyclodextrin polymers

In this paper, the controlled release of aroma compounds from cyclodextrins (CDs) and CD polymers was studied by multiple headspace extraction (MHE) experiments. Mentha piperita essential oil was obtained by Soxhlet extraction and identification of the major compounds was performed by GC–MS analysis. Menthol, menthone, pulegone and eucalyptol were identified as the major components. Retention of standard compounds in the presence of different CDs and CD polymers has been realised by static headspace gas chromatography (SH-GC) at 25°C in the aqueous or gaseous phase. Stability constants for standard compounds and for compounds in essential oil have been also determined with monomeric CD derivatives. The obtained results indicated the formation of a 1:1 inclusion complex for all the studied compounds. Molecular modelling was used to investigate the complementarities between host and guest. This study showed that β-CDs were the most versatile CDs and that β-CD polymers could perform the controlled release of aroma compounds.

Effect of Composition on Release of Aroma Compounds

The effect of oleic acid (5 and 10% v/v) and xanthan gum (0.5 and 1% wt) on partitioning and retention of ethyl acetate and diacetyl from two matrices with a different composition was investigated by applying static head space gas chromatography. Two matrices with different composition have been developed: one containing carbohydrates (xanthan gum) and in the second one, called complex matrix, lipid (oleic acid) was added. The roles of Xanthan Gum (XG) and lipid (oleic acid) on the retention of aroma compounds were pointed out. Changes in the composition of matrices exhibited a considerable effect on the air/liquid partition coefficient (Ka/l ) values at equilibrium. The kinetic study of the release from both matrices had shown a decrease of the initial rate of release (Ri) by reference with water. The rheological properties of all matrices were investigated and the flow behavior of all matrices was successfully modeled with power law and cross models. Power law model was found as the better model to describe the flow behavior of dispersions.

How composition and process parameters affect volatile active compounds in biopolymer films

Active edible films based on chitosan and containing an active aroma compound have been investigated. The influence of the composition of the film forming solution (solvent, plasticizers, nanoparticles, emulsifiers and aroma traps) and process parameters (temperature and viscosity) on drying kinetics, water content, colour, aroma compound retention and partition coefficient was studied. Solvent evaporation rate was increased by addition of ethanol. Water evaporation was delayed by glycerol. The aroma retention during film drying was directly related to the water content. The drying temperature had opposite influences according to the composition of the solvent and additives. Increasing temperature from 20 to 100 °C could increase 3 times the retention of aroma compounds. The viscosity of film forming solutions was strongly increased by biopolymer content and glycerol but reduced by carvacrol and ethanol. To improve carvacrol retention, the most efficient additive was gum arabic, followed by glycerol whereas the effect of nanoclays or emulsifiers remained weak.

Influence of temperature and NaCl on the release in aqueous liquid media of aroma compounds encapsulated in edible films

This work analyses the release of n-hexanal and d-limonene from edible films, previously encapsulated in the iota-carrageenan matrix (with and without lipid). Both volatile compounds have different physico-chemical properties. The effect of temperature (25°C and 37°C) and dissolution medium (water and 0.9% NaCl) on the release and retention of aroma compounds were studied. Hydrophobicity and wettability properties of active iota-carrageenan films were also studied and they were related with the internal and surface microstructure of films. Results highlight that d-limonene is encapsulated in the lipid phase of the films decreasing the release in the salt medium. d-limonene, the most hydrophobic, was more sensitive to the temperature changes than hexanal. Thus, this work gives an idea of the release of aroma compounds encapsulated in iota-carrageenan films in aqueous media.

Retention of aroma compounds: an interlaboratory study on the effect of the composition of food matrices on thermodynamic parameters in comparison with water

Partition coefficients give an indication of the retention of aroma compounds by the food matrix. Data in the literature are obtained by various methods, under various conditions and expressed in various units, and it is thus difficult to compare the results. The aim of the present study was first to obtain gas/water and gas/matrix partition coefficients of selected aroma compounds, at different temperatures, in order to calculate thermodynamic parameters and second to compare the retention of these aroma compounds in different food matrices. Yogurts containing lipids and proteins induced a higher retention of aroma compounds than model gel matrices. The observed effects strongly depend on hydrophobicity of aroma compounds showing a retention for ethyl hexanoate and a salting out effect for ethyl acetate. A small but noticeable decrease in enthalpy of affinity is observed for ethyl butyrate and ethyl hexanoate between water and food matrices, suggesting that the energy needed for the volatilization is lower in matrices than in water. The composition and complexity of a food matrix influence gas/matrix partition coefficients or aroma compounds in function of their hydrophobicity and to a lower extent enthalpy of vaporization.

Impact of Presoaking on Flavor of Cooked Rice

ABSTRACTSoaking rice in water for 30 min or longer before cooking is traditionally practiced in Japan, Korea, and other Asian countries. When soaked, the rice grains hydrate, develop cracks, and water is absorbed. Soaking facilitates uniform cooking and shortens cooking time. The cooked kernel is usually less firm. The present study was undertaken to determine the effects of presoaking on the flavor of cooked rice and whether flavor differences are associated with textural changes that could influence retention of aroma compounds. Eleven samples of short, medium, and long grain milled rice representing scented and nonscented rice and a wide range of amylose contents were presented to a descriptive sensory panel. For the set of all rice samples, undesirable sewer/animal flavor significantly increased and sweet taste significantly decreased with presoaking for 30 min. For individual rice samples, significantly higher sewer/animal intensity was observed with presoaking for the 2 Basmati rice samples and one of the U.S. long grain rice samples. When presoaked, sweet taste was significantly lower in one of the Basmati and Jasmine rice samples, the U.S. medium grain rice, and one U.S. long grain rice. Water‐like metallic was also significantly higher in one presoaked Basmati sample. Presoaking also resulted in significant increases in summed negative flavor attributes and significant decreases in summed positive flavor attributes for the set of all rice samples. The effects of presoaking on texture, as measured by TPA hardness and chewiness, did not explain the observed increases in negative flavor attributes. An increase in free sulfur‐containing free amino acids with presoaking could have resulted in an increase of their breakdown products, thereby contributing to the increase in sewer/animal flavor. The decreases in sweet taste and summed positive flavor attributes were likely the result of masking caused by the increases in sewer/animal and summed negative flavor attributes.

How Does Roasting Process Influence the Retention of Coffee Aroma Compounds by Lyophilized Coffee Extract?

The aims of this study were (1) to study the effect of lyophilized coffee extract on the retention of aroma compounds and (2) to study if aroma compounds selected are differently affected by the lyophilized coffee extracts obtained from conventional and Torrefacto coffee brews prepared by filter coffeemaker and by espresso coffee machine. Variable amounts of lyophilized coffee extracts, relative to coffee powder, containing different percentages of high molecular weight compounds, mainly melanoidins (value given in parentheses), were obtained: 20.9% (14.8) and 24.9% (23.3), respectively, for conventional and Torrefacto coffee brew prepared by filter coffeemaker and 18.1% (18.8) and 20.7% (57.5), respectively, for conventional and Torrefacto coffee brew prepared by espresso coffee machine. The retention of aroma compounds increased by increasing the lyophilized coffee extract concentration and was found to be dependent on the aroma compounds. The retention of aroma compounds was found to be slightly different depending on the brewing procedure employed, showing lyophilized coffee extracts obtained with espresso coffee machine had higher retention values that those extracted by filter coffeemaker. Retention capacity of lyophilized coffee extracts obtained from the conventional and the Torrefacto roasted coffee did not show differences except in the case of ethyl nonanoate.

Delayed Volatile Compound Release Properties of Self-Assembly Structures in Emulsions

Temporal release and retention of aroma compounds from structured emulsions (where unsaturated monoglycerides are added to the oil) and conventional oil-in-water emulsions were studied using in vitro dynamic headspace analysis by proton-transfer reaction mass spectrometry and static headspace analysis by gas chromatography-mass spectrometry. Under dynamic conditions, the structured emulsion exhibited delayed release compared to the oil-in-water emulsion containing the same lipid content of 5%. The time to maximum concentration T max of amphiphilic and lipophilic aroma compounds increased by a factor of 1.2 (for 3 E-hexenal) to 1.9 (for octanal). The aroma release profile of the 5% lipid structured emulsion was close to that obtained for the oil-in-water emulsion containing 10% lipid. Under static conditions, the 5% lipid structured emulsion retained more of the most lipophilic aroma compounds than its counterpart 5% oil-in-water nonstructured emulsion. The present study provides potential solutions for modulating aroma release profiles of reduced-fat foods by self-assembly structures.

Aroma of dehydrated pear products

Pear purees and cubes were dehydrated with sugars (sucrose and trehalose) addition. Freeze drying and foam-mat drying were used. Manual solid-phase microextraction (SPME) coupled with gas chromatography (GC–flame ionization detector (FID) and GC–MS) was applied to determine the changes in retention of aroma compounds in dehydrated pear purees and cubes. The best retention of aroma compounds in dehydrated pear purees was noticed in the case when freeze drying and trehalose addition were combined. In dehydrated pear cubes, previously dipped in trehalose solution, the highest aroma retention was also determined. This study showed possible application of trehalose as potentially beneficial food ingredient, with the aim to improve the quality of dehydrated fruit products, especially their aroma, and to produce superior dried fruit products or ingredients, which are widely used in food formulation.

Retention of aroma compounds by lactic acid bacteria in model food media

The interactions between aroma compounds and other particles in foods, particularly with macromolecules, have been greatly studied in order to better understand the binding of flavors in food matrices. Bacteria possess many macromolecules on their cellular surface that provide them surface properties which are involved in the physicochemical interactions between cells and interfaces. However, the interactions between bacteria and aroma compounds have not received so much attention despite the presence of bacteria in many fermented products. In order to study the retention of aroma compounds by bacteria, we have investigated the retention of esters by lactic acid bacteria with static headspace techniques. Two strains of Lactococcus lactis subsp. lactis biov. diacetylactis reflecting the natural diversity of the bacterial surface properties and two ethyl esters generally involved in the cheese flavor (ethyl acetate and ethyl hexanoate) were chosen for the experiments. The results have shown that bacteria, through their surface physicochemical properties, can interact directly with aroma compounds or in an indirect way, by changing the emulsion characteristics. However, these effects depend on the physicochemical properties of both aroma compounds and bacterial surfaces.

Formation of amylose complexes with C6-aroma compounds in starch dispersions and its impact on retention

Interactions between aroma compounds and starch matrices may increase the retention of aroma compounds. In particular, the linear amylose of starch, is able to form inclusion complexes with a wide variety of flavour compounds. The retention of four C6 aroma compounds (hexanol, hexanal, trans-2-hexenal and 2-hexanone) in model starch dispersions was measured using the exponential dilution method. The complexing behaviour of these aroma compounds with amylose and two starch dispersions was studied by differential scanning calorimetry (DSC) and X-ray diffraction, to determine the relative importance of this factor. The ability of hexanol and hexanal to induce a specific interaction with amylose is showed by both methods. This can explain their high retention in model starch dispersions. In contrast, the inability of 2-hexanone to interact with amylose explained its low level of retention.

Orange juice concentration by osmotic evaporation and membrane distillation: A comparative study

Abstract In this work, the osmotic evaporation (OE) and membrane distillation (MD) processes were compared in terms of water flux and aroma retention. The concentration of a sucrose solution, used as a model fruit juice, was carried out in a hollow fibre membrane contactor. Although a similar overall driving force was used, the flux obtained using the MD process was less than half of that observed using the OE process, due to temperature polarization effects. The transport of citral and ethyl butyrate, two aroma compounds relevant in the orange juice aroma, was also compared for both processes. A higher retention of these compounds was observed with the OE process. From these studies, it could be concluded that, the OE process has advantages over the MD process, not only in terms of water flux, but also regarding the retention of aroma compounds. Finally, the concentration of a commercial orange juice by osmotic evaporation, was carried out. Due to the presence of suspended solids and macromolecules, a higher mass transfer resistance was observed.

Retention of aroma compounds in food matrices of similar rheological behaviour and different compositions

Two matrices with a similar rheological behaviour but with a different composition have been developed: one containing carbohydrates ( d-glucose, pectin and starch) and in the second one, called complex matrix, a lipid (triolein) was added. The release of six aroma compounds is quantified by using the measurements of partition coefficients at thermodynamic equilibrium. The role of lipid (triolein) on the retention of all the aroma compounds was pointed out. The effect of carbohydrates was more complex: in comparison with water, ethyl hexanoate and trans-2-hexenal were more retained whereas diacetyl, 2-pentanone and cis-3-hexenol were “repulsed” from the matrix. The kinetic study of the release from these matrices had shown a decrease of the initial rate of release by reference with water. From carbohydrates matrix, the decrease of the release for three compounds (ethyl acetate, ethyl hexanoate, 2-pentanone) seemed to arise from the variation of diffusion and/or retention by carbohydrates. For the three other aroma compounds (diacetyl, cis-3-hexenol and trans-2-hexenal) no variation of the initial rate was registered. The comparison of the release rates from carbohydrate and complex matrices indicated the role of lipids and the comparison of the release rates from water and complex matrix showed the combined effects of texture and lipids. The decrease of initial release rate was more important in presence of lipids than in presence of carbohydrates. The most important decrease was observed with the most hydrophobic compound.

Trehalose improves flavour retention in dehydrated apricot puree

SummaryThe influence of the addition of two sugars (trehalose and sucrose) on the retention of volatiles responsible for the characteristic aroma in dehydrated apricot puree was studied. Aroma compounds of fresh and both freeze‐dried and foam‐mat‐dried apricot puree were analysed by manual headspace solid‐phase microextraction coupled with gas chromatography (GC‐FID and GC‐MS). The best retention of aroma compounds in dehydrated apricot puree was obtained when trehalose was added, regardless of the dehydration process used (freeze drying or foam‐mat drying), although, generally, a much higher retention of flavour volatiles was obtained in freeze‐dried purees. Principal Component Analysis and Cluster Analysis were applied to all the apricot purees studied to obtain a simplified view of the relationship among the aroma compounds in dehydrated apricot purees. This study gives further insights into the mechanisms that occur when trehalose is applied as an additive and will enable the development of new processes to maximize this effect and to produce superior dried products.

Composition rather than viscosity modifies the aroma compound retention of flavored stirred yogurt.

The influence of thickening agents (modified starch/pectin mixture 0 and 7 g/L) and mechanical treatment (low, medium, and high) on the retention of esters (pentyl acetate and ethyl pentanoate), aldehydes (hexanal and (E)-2-hexenal), and a lactone (gamma-octalactone) in low-fat flavored stirred yogurts were investigated under equilibrium conditions. In the range studied, the thickening agent and mechanical treatment had little influence on aroma compound retention compared to the decreasing effect of increasing dairy protein concentration on aldehyde retention and the "salting out" effect of carbohydrates on esters. Moreover, experiments in dynamic mode (study of the release of hexanal when yogurts were heated) showed, in the conditions studied, that heat and mass transfer coefficients were not influenced by any of the studied factors (thickening agents and mechanical treatment). These results under static and dynamic conditions are not related to the significant decreasing effect of thickening agents on apple sensory scores associated with hexanal, observed in a previous sensory study. Thus, this sensory effect of thickening agents may be due to sensory interactions between perceptions rather than physicochemical interactions.

Retention of aroma compounds in basil dried with low pressure superheated steam

Basil leaves were dried using either conventional hot air (50, 60 and 70 °C) and low pressure superheated steam (LPSS) dryers. The effect of the drying method on the retention of some volatile compounds was evaluated. The extraction from the fresh and dried products was performed by the simultaneous distillation–extraction technique. Identification and quantification was performed by capillary gas chromatography–mass spectrometry (GC–MS) and gas chromatography (GC) respectively. The identified compounds were 23, with 61% of monoterpenes, 26% of aromatic and 13% of aliphatic compounds, out of which those characteristic of this spice were detected (1,8-cineole, methyl chavicol, methyl cinnamate and linalool). Results show that in the LPSS dried product, the original aroma profile of the fresh vegetable is kept almost constant, while air-dried product shows a significant variation in the relative proportions of aroma compounds. The conclusion is that the LPSS drying technique renders a better product in terms of the aroma compounds content, than the conventional air-drying, with the advantage of being cheaper.

Partition coefficients of aroma compounds in polysaccharide solutions by the phase ratio variation method

The partition coefficients ( K) of aroma compounds (a homologous series of ketones, hexanal, t–2-hexenal, ethyl butanoate and 1-hexanol) in polysaccharide solutions were determined by the phase ratio variation method (PRV method) using a headspace autosampler. This method enabled easy determination of the partition coefficients of volatile compounds in a gas/liquid system without external or internal calibration, and the results agreed well with published data obtained by direct method. Measurements of K at different temperatures enabled the investigation of aroma compound retention by maltodextrin and β-cyclodextrin during heat treatment. In a maltodextrin solution, retention depended on the hydrophobicity of aroma compounds and it was favoured by the increase of temperature (from 60 to 80 °C). In a β-cyclodextrin solution, temperature variations produced different effects on the retention of aroma compounds and could reveal differences in the nature of the interaction with β-cyclodextrin.

Distribution of volatile compounds in the pulp, cloud, and serum of freshly squeezed orange juice.

The quantitative distribution of volatile compounds in the pulp, cloud, and serum of a freshly squeezed orange juice (cv. Naveline) was measured. Juice monoterpene and sesquiterpene hydrocarbons were primarily recovered from the pulp (74.0 and 87.2%, respectively) and cloud (7.3 and 14.9%, respectively). Esters and monoterpene alcohols were mainly found in the serum (90.4 and 84.1%, respectively). Long chain aliphatic aldehydes tend to concentrate in the pulp. The relative proportions of individual volatile compounds were similar in the pulp and cloud. Pulp and cloud alcohol insoluble residues exhibited similar compositions; half of them are made of nonwall proteins, and the rest are made of cell wall materials. Pulp and cloud total and neutral lipids had similar fatty acids distributions, although the cloud was much richer in total lipids than the pulp. No relationship was found between the retention of aroma compounds in the pulp or cloud and their AIR and lipid content or composition.

Effect of texture and microstructure on flavour retention and release

Abstract A review is given of the effects of texture and (micro)structure on the retention of aroma compounds during processing and storage and on the aroma release and perception during consumption. Examples are given of the effect of viscosity on flavour retention in model systems and during fluid bed drying. Further, there are examples of the effect of product inhomogeneity on flavour retention and release, covering the retention of volatiles during hard candy manufacturing and the entrapment of the volatile compounds in the lipid and hydrophilic phase during baking of crackers. Examples of the effect of encapsulation on flavour retention are also given with special attention being paid to the effect of capsule structure. Texture and microstructure have less influence on the flavour release during consumption, because the microenvironment of the flavour compounds is broken down to a consistency that is suitable to be swallowed. Nevertheless, here too examples can be given that show the effect of texture and microstructure on the release of liquid and encapsulated flavourings.

Retention of aroma compounds in starch matrices: competitions between aroma compounds toward amylose and amylopectin.

The retention of three aroma compounds-isoamyl acetate, ethyl hexanoate, and linalool--from starch-containing model food matrices was measured by headspace analysis, under equilibrium conditions. We studied systems containing standard or waxy corn starch with one or two aroma compounds. The three studied aroma compounds interact differently: ethyl hexanoate and linalool form complexes with amylose, and isoamyl acetate cannot. However, in systems containing one aroma compound, we observed with both starches a significant retention of the three molecules. These results indicate that amylopectin could play a role in the retention of aroma. In systems containing two aroma compounds in a blend, the retentions measured for isoamyl acetate and for linalool were either equal to or less than those in systems where they were added alone. This phenomenon was attributed to competition between aroma compounds to bind with starch. The retention of aroma compounds blended in starch-based systems gave us additional information which confirmed that interactions occur not only with amylose but also with amylopectin.