Distribution Of Aroma Compounds Research Articles

A predictive model for flavor partitioning and protein-flavor interactions in fat-free dairy protein solutions

Flavor perception is directly related to the concentration of aroma compounds in the headspace above a food matrix before and during consumption. With the knowledge of flavor partition coefficients, the distribution of aroma compounds within the food matrix and towards the headspace can be calculated. In this study static headspace measurements and modelling are combined to predict flavor partitioning of a wide range of flavor compounds above fat-free dairy protein mixture solutions. AFFIRM® (based on Atmospheric Pressure Chemical Ionization-Mass Spectrometry) was used to measure the static headspace concentrations of 9 flavor compounds (3 esters, 3 aldehydes and 3 alcohols) above protein solutions with different concentrations and ratios of sodium caseinate and whey protein isolate. Proteins had a small pushing out effect, leading to increased release of hydrophilic flavor compounds. This effect was negligible for more hydrophobic compounds, where clear retention was observed. An increased total protein concentration and higher whey to casein ratio increased the retention for all flavor compounds. Within the same chemical class, the retention increased with chain length. The experimental data was interpreted with a model describing flavor partitioning in protein solutions (Harrison & Hills, 1997), thereby enabling to extract protein-flavor binding constants. A clear power law was found between the protein-flavor binding constant and log P (octanol-water partition coefficient). Assuming solely non-specific hydrophobic interactions gave satisfying partitioning predictions for the esters and alcohols. For aldehydes specific chemical interactions with proteins turned out to be significant. This rendered a binding constant for whey protein that is 5 times higher than for caseinate in case of esters and alcohols, and 3 times higher in case of aldehydes. The model can accurately predict equilibrium flavor partitioning in dairy protein mixtures with only the knowledge of the octanol-water partition coefficients of the flavor compounds, and the composition of the protein mixture.

Impact of flavour solvent on biscuit micro-structure as measured by X-ray micro-Computed Tomography and the distribution of vanillin and HMF (HPLC)

The influence of flavour solvent, propylene glycol (PG) and triacetin (TA), was investigated on the micro-structure (as measured by X-ray micro-Computed Tomography, X-ray μCT) and aroma compound distribution (as measured by HPLC) within shortcake biscuits. X-ray μCT scanning showed biscuits made with PG had smaller pores and higher porosity than biscuits made with TA. Vanillin distribution across the biscuits was not homogeneous and was found at higher concentrations in the centre of the biscuits than the edge or bottom. The baked aroma compound 5-hydroxymethyl-furfural (HMF) was present at higher concentrations at the surface of the biscuits where Maillard chemistry is presumed to occur at its highest rate. The type of solvent had a significant effect on the total concentration and distribution of aroma compounds (p < 0.05). TA biscuits retained greater vanillin and more HMF was formed during baking when compared to PG biscuits. The core of TA biscuits had (on a relative scale) a much greater vanillin and lower HMF concentration than PG biscuits when compared to their periphery. Although this may be due to different physicochemical properties of the two solvents and varying levels of interactions with other ingredients, the micro-structure differences indicated by X-ray μCT image analysis illustrate one potential route by which the flavour solvent may be influencing the generation and stability of biscuit aroma compounds.

Multivariate analysis of retention and distribution of aroma compounds in barrier dispersion coatings

AbstractThe influence of drying conditions, latex type, talc content and amount of added aroma compounds on the retention and distribution of aroma compounds in barrier dispersion coatings was explored using static headspace gas chromatography combined with multivariate data analysis. The model aroma system consisted of an alcohol, an ester, an aldehyde, a ketone and two terpenes. Four latex grades based on styrene‐acrylate and styrene‐butadiene were studied. It was found that non‐polar aroma compounds were retained best in styrene‐butadiene latex, while polar ones were retained more in the styrene‐acrylate latex. Talc increased the retention of all the aroma compounds. The retention of polar compounds was higher with shorter drying times, which is probably due to greater losses during the later steps of the film formation process when internal water was evaporated. Polarity and talc also affected the partition of the aroma compounds between air and film. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Distribution of aroma in a starch–polysaccharide composite gel

The location of different aroma compounds in a gel containing sucrose, cross-linked waxy corn starch and carrageenan was investigated. Different systems were designed by varying the carrageenan and the sucrose contents and were flavoured with a mixture of aroma compounds. These systems are described as composite gels formed by a dispersed phase composed of swollen starch granules and a continuous phase containing the other polysaccharide. The separation of the two phases was done by centrifugation. The concentration in aroma compounds was measured in both phases and a partition coefficient was calculated for every compound in the different formulations. When the gel contained only starch, the distribution between the two phases for all aroma compounds was uniform. When carrageenan was present, the aroma compounds were found to be more concentrated in the continuous phase than in the dispersed phase. The addition of sucrose induced the opposite effect with a greater concentration of aroma compounds in the dispersed phase. The combination of these results with those of the gas/matrix partition is finally discussed to understand how the distribution of aroma compounds in a biphasic system influences aroma release in the headspace under equilibrium.

Diffusion of Aroma Compounds into Packaging Films under High Pressure

Diffusion of the aroma compounds p-cymene and acetophenone into three different packaging films was studied at 500 MPa for kinetic measurement, and in the range of 0.1–450 MPa for measurement of the diffusion rate as a function of pressure. Absorption of aroma compounds was lower in pressurized than in nonpressurized polymeric films. PET/A1/LDPE was impermeable to either substance; absorption was limited to the LDPE lining inside. Distribution of aroma compounds to solution and films depended on their polarity; acetophenone virtually did not diffuse into the films. Measurements of the diffusion rate as a function of pressure has shown a diffusion barrier in the range of 100–200 MPa for the films investigated. The assumption that this is due to transition into the glassy state has been supported by studies of diffusion as a function of temperature.

Aroma values--a useful concept?

Rapidly increasing knowledge about the high complexity of food aromas requires selection or ranking procedures as to the importance of the particular components for flavour impression. For this purpose the concept of aroma values has been discussed which calculates quantitative data in connection with aroma effectiveness of the compounds. The simplification of the concept with respect to the practical application, however, can change the natural system and lead to erroneous conclusions. There are not only interactions between aroma substances of sensoricphysiological character which may not be ignored. Physical conditions like lipid content, distribution of aroma compounds between aqueous and lipid phase or the sorption of volatile substances to the polymer nutrients in foodstuffs are of influence, too.