Release Of Aroma Compounds Research Articles

Computational Modeling of Food Oral Breakdown Using Smoothed Particle Hydrodynamics

AbstractThe manner in which food breaks down during mastication directly influences not only perception of texture but also the temporal release of taste and aroma compounds and perception of flavor. Although sampling chewed food during mastication allows local quantitative measurement of particle properties and taste and aroma compound concentrations, it is not possible to measure the full spatiotemporal variations of these quantities. Computational modeling can be used to estimate the values of these quantities throughout the volume of the oral cavity at any point in the chewing cycle or allow controlled parametric analysis that would be impractical in physical experimentation. We present a coupled biomechanical‐smoothed particle hydrodynamics model of human mastication and predict the mechanical behavior and breakdown of two agar model foods. The results of these simulations show that our model has the potential to enhance the understanding of the relationship between food structure and oral breakdown during mastication.Practical ApplicationsDevelopment of a computational model of chewing and oral breakdown will enhance the understanding of the relationship between food structure, oral breakdown and flavor release during mastication. A functional model may be utilized to design the material and structural properties of food products that will break down in a desired fashion during chewing. Future model extensions that facilitate the prediction of flavor release given known mechanical properties will facilitate how to add flavor to provide a target sensory profile. This knowledge will fast‐track innovations in new food product development and facilitate reformulation of healthier food products without compromising sensory quality. In the future, the ability to predict the physical and chemical stimuli may facilitate the prediction of sensory perception from first principles.

Comparison of volatile release in hydrocolloid model systems containing original and regio selectively carboxylated β-glucans

The release of 13 volatile compounds in hydrocolloid model systems containing original or regio selectively carboxylated β-glucan at different pHs was analyzed using static headspace gas chromatographic analysis. There was significant difference in the release of most compounds, except for butyl propionate, 2-propanol, and 2,3-butanedione, in both the original and carboxylated β-glucan hydrocolloid model systems. However, the effects of pH in the hydrocolloid systems were not significant for most compounds studied, except for butyl propionate, ethyl caproate, 3-methyl-1-butanol, 2,3-butanedione. In particular, the release of 2,3-butanedione was considerably decreased at pH 10 compared to pH 4 and 7. In addition, the partition coefficient of each ethyl ester compound was measured to investigate the release of aroma compounds using the phase ratio variation (PRV) method. The difference in the partition coefficients of short and medium chain-ethyl esters between the reference solution and the original/carboxylated β-glucan solutions was not significant. In contrast, the release of relatively long chain-ethyl esters (ethyl caprylate and ethyl nonanoate) from both the original and carboxylated cellulose solutions was decreased compared to that in reference solution.

Saliva from Obese Individuals Suppresses the Release of Aroma Compounds from Wine

BackgroundRecent evidence suggests that a lower extent of the retronasal aroma release correspond to a higher amount of ad libitum food intake. This has been regarded as one of the bases of behavioral choices towards food consumption in obese people. In this pilot study we investigated the hypothesis that saliva from obese individuals could be responsible for an alteration of the retro-nasal aroma release. We tested this hypothesis in vitro, by comparing the release of volatiles from a liquid food matrix (wine) after its interaction with saliva from 28 obese (O) and 28 normal-weight (N) individuals.Methods and FindingsAmplicon sequencing of the 16S rRNA V4 region indicated that Firmicutes and Actinobacteria were more abundant in O, while Proteobacteria and Fusobacteria dominated in N. Streptococcaceae were significantly more abundant in the O subjects and constituted 34% and 19% on average of the saliva microbiota of O and N subjects, respectively. The Total Antioxidant Capacity was higher in O vs N saliva samples. A model mouth system was used to test whether the in-mouth wine aroma release differs after the interaction with O or N saliva. In O samples, a 18% to 60% significant decrease in the mean concentration of wine volatiles was detected as a result of interaction with saliva, compared with N. This suppression was linked to biochemical differences in O and N saliva composition, which include protein content.ConclusionMicrobiological and biochemical differences were found in O vs N saliva samples. An impaired retronasal aroma release from white wine was detected in vitro and linked to compositional differences between saliva from obese and normal-weight subjects. Additional in vivo investigations on diverse food matrices could contribute to understanding whether a lower olfactory stimulation due to saliva composition can be a co-factor in the development/maintenance of obesity.

A novel approach for studying the indoor dispersion of aroma through computational fluid dynamics

ABSTRACTWe propose a mechanistic modelling approach for studying the indoor dispersion of aroma compounds which are released from, for instance, food products. The approach combines the indoor velocity field with a release model for aroma compounds. The release mass flux is expressed as a function of key variables such as mass transfer and gas–liquid partition coefficients, and the source geometry. The transport properties of ambient air are assumed to be independent of the aroma concentration; hence release and dispersion problems can be solved separately. First, the velocity field is obtained as solution of the fluid flow problem through computational fluid dynamics (CFD). The turbulent velocity field is then used to predict the time evolution of concentration of an aroma compound released by a constant rate source, in an initially aroma‐free environment. These results are interpreted in terms of a step response function. The aroma concentration as a function of time is finally estimated by convolving the possibly time‐varying release mass flux and the response function associated with the position of interest. The modelling approach is flexible and computationally effective, since different release models as well as the release of distinct aroma compounds can be directly studied by taking into account a same velocity field, without any additional CFD simulation. The validity of the approach is assessed from measurements of aroma concentration in a 140 m3 room, under constant release mass flux. The approach is also illustrated for a case where the release mass flux is not constant in time. Copyright © 2013 John Wiley & Sons, Ltd.

Modifying PTR-MS operating conditions for quantitative headspace analysis of hydro-alcoholic beverages. 2. Brandy characterization and discrimination by PTR-MS

The characterization of the release of aroma compounds from beverages can bring pertinent information that can help in better understanding aroma perception. However, this kind of measurement is complex for high ethanol-containing beverages and needs to be adapted or optimized. Increasing the mean collision energy in the drift tube via the E/N ratio can be an interesting solution to prevent H3O+ depletion when high ethanol-containing samples, as distilled beverages for instance, are analyzed. However, the higher collision energy induced by these conditions impacts ionization reactions due to an increased number of fragmentation mechanisms, which could make data analysis difficult. The aim of the present study was to highlight the pertinence of using strong operating conditions (E/N=454Td) compared to reference conditions (E/N=120–140Td) for the analysis of 40% (v/v) ethanol-containing beverages. The first step was to better understand product ion distributions of 11 aroma compounds, known to be important for the overall flavor of brandies and prepared in 40% (v/v) ethanol/water solutions, at both operating conditions. As a validation, eight commercial brandies from different brands and with different aging times were analyzed under the two operating conditions. It appeared that the E/N value did not impact product ion distribution, but changed their relative abundances: increasing the E/N ratio increased fragmentation mechanisms, resulting in the detection of a greater proportion of low mass fragments to the detriment of protonated ions issued from aroma compounds. The response linearity of the PTR-MS was not modified at strong operating conditions. The application of these conditions to the analysis of brandies highlighted that, in spite of modifications on ionization mechanisms, products can be correctly discriminated, mainly according to their aging time.

Healthy trends affect the quality of traditional meat products in Mediterranean area

The actual trend in the meat industry is the development of healthy meat products with reduced fat and salt contents. In high quality products such as traditional sausages which are characterized by an absence of fermentation and long ripening times, it is essential to get a meat product with a high aroma quality but at the same time healthy composition. This reduction represents an added value to the production and consumption of traditional sausages because flavour is one of the most important characteristics for consumers. The problem associated to salt and fat reduction in dry sausages is the loss in sensory properties, especially in aroma. The reason is that sodium has a synergetic effect with the food matrix, enhances the sensory characteristics and produces the release of volatile aroma compounds from the food matrix. On the other hand, fat affects the generation of volatile compounds from which it is a precursor and modifies flavour perception due to the changes in the interaction and release of volatile compounds. Few references have studied the effect of salt and fat reduction in the aroma of traditional dry cured sausages. This manuscript summarized the effect of salt and fat reduction in flavour development of traditional sausages and its effect on aroma perception. Traditional foods should be adapted to new trends without losing their identity and sensory characteristics.

Metabolic flux analysis during the exponential growth phase of Saccharomyces cerevisiae in wine fermentations.

As a consequence of the increase in global average temperature, grapes with the adequate phenolic and aromatic maturity tend to be overripe by the time of harvest, resulting in increased sugar concentrations and imbalanced C/N ratios in fermenting musts. This fact sets obvious additional hurdles in the challenge of obtaining wines with reduced alcohols levels, a new trend in consumer demands. It would therefore be interesting to understand Saccharomyces cerevisiae physiology during the fermentation of must with these altered characteristics. The present study aims to determine the distribution of metabolic fluxes during the yeast exponential growth phase, when both carbon and nitrogen sources are in excess, using continuous cultures. Two different sugar concentrations were studied under two different winemaking temperature conditions. Although consumption and production rates for key metabolites were severely affected by the different experimental conditions studied, the general distribution of fluxes in central carbon metabolism was basically conserved in all cases. It was also observed that temperature and sugar concentration exerted a higher effect on the pentose phosphate pathway and glycerol formation than on glycolysis and ethanol production. Additionally, nitrogen uptake, both quantitatively and qualitatively, was strongly influenced by environmental conditions. This work provides the most complete stoichiometric model used for Metabolic Flux Analysis of S. cerevisiae in wine fermentations employed so far, including the synthesis and release of relevant aroma compounds and could be used in the design of optimal nitrogen supplementation of wine fermentations.

Multivariate-parameter optimization of aroma compound release from carbohydrate–oil–protein model emulsions

Optimization for retention and partition coefficient of ethyl acetate in emulsion model systems was investigated using response surface methodology in this paper. The effects of emulsion model ingredients, tragacanth gum (TG) (0.5–1wt%), whey protein isolate (WPI) (2–4wt%) and oleic acid (5–10%, v/v) on retention and partition coefficient of ethyl acetate were studied using a five-level three-factor central composite rotatable design (CCRD). Results showed that the regression models generated adequately explained the data variation and significantly represented the actual relationships between the independent and response parameters. The results showed that the highest retention (97.20±0.51%) and lowest partition coefficient (4.51±0.13%) of ethyl acetate were reached at the TG concentration 1wt%, WPI concentration 4wt% and oleic acid volume fraction 10% (v/v).

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.

Waste grape skins thermal dehydration: potential release of colour, phenolic and aroma compounds into wine

Exploitation of grape waste material is scarce. One of the main issues to deal with is its high moisture content, as it causes spoilage and degradation of valuable compounds. In order to assess this limitation, four different Vitis vinifera waste grape skins from the juice industry were dehydrated at 60, 90 and 100°C. Characterisation of dehydrated waste grape skins (DWGS) was firstly done in wine model solution to evaluate the release of colour, phenolic and volatile compounds. Colour of DWGS-60°C solutions was similar to the control one (freeze-drying) in terms of red and yellow components regardless of the variety. Samples of Garnacha Tintorera, Bobal and AMIX dehydrated at 60°C showed the highest content of low molecular weight phenolic compounds. Bobal DWGS-60°C released the highest concentration of volatiles. An assay by direct addition of Bobal DWGS-60°C into a white wine demonstrated the potential of these residues for producing rosé wines.

Basic characterization and partial purification of β-glucosidase from cell-free extracts of Oenococcus oeni ST81

This study was designed to characterize a β-glucosidase of Oenococcus oeni ST81, a strain isolated from a Spanish wine of the origin appellation Ribeira Sacra. The β-glucosidase of O. oeni ST81 seems to have a periplasmic localization into the cells. This activity was strongly inhibited by gluconic acid, partially inhibited by glucose and not inhibited by fructose, lactate, malate, mannitol or sorbitol. Ethanol increased the activity of this enzyme up to 147%. Among the several metal ions assayed, only Fe²⁺ (10 mmol l⁻¹) and Cu²⁺ (5 mmol l⁻¹) exhibited a partial inhibitory effect (40%). This enzyme was partially purified using a combination of ammonium sulfate precipitation and chromatographic methods. The single peak because of β-glucosidase in all chromatographic columns indicates the presence of a single enzyme with an estimated molecular mass of 140 kDa. The calculated K(m) and V(max) values for 4-nitrophenyl-β-D-glucopyranoside were 0·38 mmol l⁻¹ and 5·21 nmol min⁻¹, respectively. The enzyme was stable at pH 5·0 with a value of t(1/2) = 50 days for the crude extract. The β-glucosidase of O. oeni ST81 is substantially different from those characterized from other wine-related lactic acid bacteria (LAB), such as Lactobacillus plantarum and Lactobacillus brevis; however, it appears to be closely related to a β-glucosidase from O. oeni ATCC BAA-1163 cloned into Escherichia coli. The periplasmic localization of the enzyme together with its high tolerance to ethanol and fructose, the low inhibitory effect of some wine-related compounds on the enzymatic activity and long-term stability of the enzyme could be of interest for winemaking. Information regarding a β-glucosidase from O. oeni ST81 is presented. Although the release of aroma compounds by LAB has been demonstrated, little information exists concerning the responsible enzymes. To our knowledge, this study contains the first characterization of a native β-glucosidase purified from crude extracts of O. oeni ST81.

Dynamic Changes in Volatile Compounds during Fermentation of Cabernet Sauvignon Grapes with and without Skins

Volatile compounds in wines arise from many sources: they may be extracted from the grapes during fermentation, formed by yeast during fermentation, and/or arise during postfermentation storage and processing. Factors influencing extraction of volatiles from grapes during fermentation have not been widely studied; an improved understanding of the processes and mechanisms involved in the formation or release of wine aroma compounds from grapes during fermentation could help winemakers to optimize or control wine composition and aroma. In this work, we studied the effects of different skin contact times on changes in concentrations of volatile aroma compounds during fermentation of Cabernet Sauvignon grapes. Headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry was used to monitor the volatile compounds produced during fermentation. Duration and timing of the skin contact during fermentation showed a measurable effect on volatile composition. Some compounds reached higher concentrations in fermentations performed with skins, while, in other cases, skins acted to “bind” or delay release of volatiles, particularly β-damascenone.

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.

Effect of aromatic precursor addition to wine fermentations carried out with different Saccharomyces species and their hybrids

This work explores the ability of different yeast strains from different species of the genus Saccharomyces (S. cerevisiae, S. uvarum and S. kudriavzevii) and hybrids between these species to release or form varietal aroma compounds from fractions of grape odourless precursors. The de novo synthesis by the yeasts of some of the varietal aroma compounds was also evaluated. The study has shown that de novo synthesis affects some lipid derivatives, shikimic derivatives and terpenes in all species and hybrids, with some remarkable differences amongst them. The release or formation of aroma compounds from precursors was found to be strongly linked to the yeast or hybrid used, and the triple hybrid S. cerevisiae × S. bayanus × S. kudriavzevii in particular and secondarily the hybrid S. cerevisiae × S. bayanus were highly efficient in the production of most varietal aroma compounds, including γ-lactones, benzenoids, volatile phenols, vanillin derivatives and terpenols. The presence of precursors in the fermenting media caused a surprising levelling effect on the fermentative aroma composition. Altogether, these results suggest that it is possible to modulate wine aroma by employing different yeast species in order to create new wines with different aromatic notes.

Aroma release and sensory perception of fruit candies model systems

The release of volatile compounds from food matrices is governed by kinetic and thermodynamic phenomena. Intrinsic properties of the food matrix, extrinsic factors (temperature, pressure) as well as the interaction with non volatile compounds in the food matrix are involved in both the release rate and the aroma concentration in equilibrium. The objective of this study was to investigate the influence of the composition (i.e. gelling agents - gelatine, starch pectin- and sugars) on the release and sensory perception of aroma compounds from candy model systems added with a standard strawberry flavour. Model candies were prepared by using gelatine gelatine and starch, starch and pectin (P). All samples were added with the same concentration of a strawberry aroma (0.25%db) and with the exception of Aes, all models, after setting, were dried under the same process conditions and stored in HDPE bags until analysis. Evaluations of the release of aroma compounds under equilibrium conditions were carried out by Head Space Gas Chromatography and Electronic Nose both on the model candies and the same submerged in water to mimic the dissolution in the mouth. The kinetics of the aroma release from the models during dissolution to reach the equilibrium were also investigated. Sensory evaluations and mechanical analyses under standardised procedure were also carried out. The partitioning of strawberry aroma compounds from the candy model systems at equilibrium in the head space was highly affected by the gelling agent type and sugar content. The affinity of the aroma compound for the biopolymer/s of the candy model system and structural properties are implied in the different release in the vapour phase of EA (more polar) and EH (more apolar). The kinetics of the volatiles release from the candies in water varied depending on the aroma nature and the physical properties of the systems as affected by the gelling agent

In-mouth aroma compound release during cheese consumption: Relationship with food bolus formation

The present study describes the changes in mechanical properties and saliva incorporation for cheese samples with different composition and texture, and their influence on the rate of aroma release. Chewing work per cycle, salivary flow rate and chewing rate varied highly among subjects. Despite the differences in cheese hardness, at the end of mastication, bolus texture was the same for cheeses with the same lipid content. Low-fat cheeses gave harder bolus than high fat ones, despite being chewed longer, with higher work per cycle and more moisture. Salivary flow rate did not vary among cheese samples but, at the end of mastication, the amount of saliva in boluses differed depending on the hardness and fat content of cheeses. Differences in aroma release pattern between subjects could be explained by the combined effect of both chewing process and salivary flow rates.

Retention–release equilibrium of aroma compounds in polysaccharide gels: study by quantitative structure–activity/property relationships approach

AbstractThe nature and amount of constituents in food greatly influence aroma release. Pectins and carrageenans are common used thickeners, but their effect on the release of aroma compounds has been studied more frequently for non‐homogeneous products than for thickeners separately. The purpose of this work was to study and compare their respective effects in simple model systems. In this way, the release of 13 aroma compounds was analysed by headspace analysis at equilibrium in pure water, ι‐carrageenan and pectin gels. To evaluate the influence of the chemical structure of aroma compounds on retention/release equilibrium between vapour phase and gels, we used a quantitative structure–activity/structure–property relationships (QSAR/QSPR) approach. Our present aim was first of all to identify some relevant structural properties related to the retention and then to propose a qualitative interpretation. We used the genetic function approximation (GFA) available in the Cerius2 package to generate (QSAR) equations with one, two and three variables, with or without constant adding. The two variables equations without constant adding obtained involve the descriptors Jurs‐PNSA‐1 and Jurs‐WNSA‐2 for retention in water and in carrageenan gel, Jurs‐RPSA and CHI‐V‐3_P for retention in pectin gel. This result highlights that ι‐carrageenan does not modify the nature of interactions between aroma and water molecules, but suggests that interactions with pectin are somewhat different, involving positively charged surface areas in the retention phenomenon. Copyright © 2010 John Wiley & Sons, Ltd.

Effects of texture and temperature on the kinetic of aroma release from model dairy custards

The structure of a foodstuff, and its perceived texture, are important characteristics involved in the sensory availability of flavour compounds released during the food consumption. This study identifies the effect of texture on the dynamic release of aroma compounds under simulated oral conditions (temperature and shearing). Two custard desserts, with two levels of texture but the same composition, flavoured with four aroma compounds, were analysed. The rheological behaviour of the custards and the release of aroma compounds (SPME analysis) were simultaneously followed, using a mouth simulator. The custard with the lowest texture level showed the highest kinetic release for all aroma compounds studied. With fast increase of temperature (10–25 °C), the decrease in viscosity of the custards and its impact on flavour release seemed to be less important than the heat transfer inside the products and its effect on partition of aroma compounds.

Retention/release equilibrium of aroma compounds in fat-free dairy gels

The replacement of fat by thickeners in fat-free yogurts leads to an important modification of aroma compound partitioning, with an impact on aroma perception. Investigation of retention/release equilibria allows a good understanding of aroma compound behaviour depending on food composition. Vapour/liquid equilibria of ten aroma compounds (two esters, two ketones, three aldehydes and three alcohols) in several media were studied to investigate the influence of pectin addition to fat-free dairy gel on the retention/release equilibrium. The partition coefficient of each aroma compound was measured by headspace analysis at equilibrium in six media (pure water, low-methoxylated pectin gels and dairy gels with or without added pectin). The release of aroma compounds was similar in the aqueous media (pure water and pectin gels) on the one hand and in the dairy gels on the other hand. However, a trend to greater release occurred with the addition of pectin in both cases. Four aroma compounds were more retained in dairy gels than in water and pectin gels. No relationship appeared between retention and either the chemical function or hydrophobicity (logP values) for the entire set. However, several subsets showed a linear correlation between K and logP values. These results suggest that other structural properties than hydrophobicity are probably involved, changing the retention/release behaviour of aroma compounds according to the matrix composition. In order to probe the interactions, further experiments with a larger set of aroma compounds followed by molecular modelling interpretation are needed.