Influence of Lipid Fraction, Emulsifier Fraction, and Mean Particle Diameter of Oil-in-Water Emulsions on the Release of 20 Aroma Compounds

Abstract

The influence of compositional and structural properties of oil-in-water emulsions on aroma release was examined under mouth conditions. The lipid (0.40 and 0.65) and emulsifier fractions (0.007, 0.010, and 0.014) were varied, as well as the mean particle diameter of the dispersed phase (0.60, 0.73, 0.85, and 1.10 microm). Aroma compounds were isolated in a model mouth system and quantified by gas chromatography-mass spectrometry. Studies were carried out to separate effects on the thermodynamic and the kinetic components of aroma release using equilibrium headspace analysis to distinguish the thermodynamic component. The lipid phase of the emulsions was composed of sunflower oil and the emulsifier phase was Tween 20. The release of 20 aroma compounds was evaluated; the compounds included alcohols (1-propanol, 1-butanol, 3-methyl-1-butanol, 2-pentanol, 1-hexanol, and 2-nonanol), ketones (diacetyl, 2-butanone, 2-heptanone, 2-octanone, and 2-decanone), esters (ethyl acetate, propyl acetate, butyl acetate, and ethyl butyrate), aldehydes (hexanal, heptanal, and octanal), a terpene (alpha-pinene), and a sulfur compound (dimethyl sulfide). Decrease in lipid fraction and emulsifier fraction, as well as increase in particle diameter, increased aroma release under mouth conditions. Differences between groups of compounds and between compounds of homologous series with varying chain lengths were found. Changes in particle diameter had a considerable effect on the thermodynamic component of aroma release, whereas hardly any influence of the lipid fraction and emulsifier fraction was observed. Lipid fraction, emulsifier fraction, and particle diameter affected the kinetic component of aroma release, which could partially be attributed to changes in viscosity.

Influence of oil‐in‐water emulsion characteristics on initial dynamic flavour release

“…No influence of a possible enrichment of flavour molecules at the interfacial membrane 27 was established. These results are in agreement with the work by van Ruth et al 15 and are explained by a constant fluctuation of emulsifier molecules at the interfacial area between emulsifier molecules at the droplet surface, molecules dissolved in the aqueous phase and micellar aggregates. 28 The results also suggest that volatiles sensitive to temperature and pressure do not necessarily have to be added before homogenisation, pasteurisation or sterilisation (eg flavoured milk), but can also be added afterwards.…”

“…Static headspace studies showed that O/W emulsions with decreased oil droplet diameters resulted in increased flavour release in the case of non-polar compounds, and no or small effects were obtained for more hydrophilic volatiles. 14 The opposite was found by van Ruth et al, 15 who showed in static as well as in dynamic measurements that increased droplet diameters resulted in significantly higher release rates for many aroma compounds, which was also concluded from mathematical modelling results of flavour release from emulsions. 30 Although eight of 13 volatiles showed slightly higher release from emulsions with smaller droplets (Table 4), the effect of oil droplet size on the initial dynamic flavour release under simulated in-mouth conditions 26 was insignificant (ANOVA, p < 0.05).…”

“…In other works, constant emulsifier concentrations for different oil fractions were reported. 21,36 Van Ruth et al 15 found the concentration of Tween 20 to significantly affect the static and the dynamic headspace above emulsions and explained these results by microstructural effects at the oil/water interface. However, no objective criterion for the applied emulsifier amounts was reported, nor the overall mass balance of the emulsifier partitioned in the emulsion.…”

Research on Evaluation Emulsify Ability for Polyphenols in Vegetable Oils

“…Vegetable oils play important role in human life, including contributions of essential nutrients, energy, mouth-fell, flavor, palatability, emulsifying, and complex characteristics to food products [1][2][3]. Vegetable oils are obtained from beans or seeds by pressing and/or by solvent extraction.…”

Lipid molarity affects liquid/liquid aroma partitioning and its dynamic release from oil/water emulsions

“…Nonionic emulsifiers, such as Tweens, or surfactants based on MAG and DAG did not serve as barriers at the oil interface nor as solubilizers in terms of micelles (4)(5)(6). On the other hand, the oil fraction of an oil/water emulsion had a considerable influence on the partitioning of flavors, which in turn determined their static and dynamic release (7)(8)(9)(10)(11)(12)(13). These processes depend on the polarity of the volatiles and are governed by Nernst's law of partitioning (6,13).…”