Flavor release and stability comparison between nano and conventional emulsion as influenced by saliva.

Flavour release and emulsion stability depend on volatile organic compounds' environmental conditions, food microstructure, and physicochemical properties. The effect of pH (3.5 vs 7.0) and saliva addition on stability and flavour release from nano and conventional emulsions was investigated using particle size, charge and Lumisizer measurments. Larger particle sizes were observed at lower pressures and in saliva-containing emulsions. At 1700 bar, nano-emulsions (below 150 nm) were created at pH 3.5 and 7.0 including saliva-containing emulsions. As was clear from the creaming velocity measurements, saliva addition decreased the emulsion stability by reducing particle charges and increased viscosity by more than 50%, especially when prepared at pH 3.5 closer to the isoelectric point of the used emulsifier ß-lactoglobulin (pH 5.2). (5.2). Flavour release from emulsions was measured at equilibrium using a phase ratio variation to determine partition coefficients and dynamically using an electronic nose. Partition coefficients of the flavour compounds for most conditions were two to four times lower in emulsions prepared at pH 7.0 than at pH 3.5 and in emulsions without saliva. Emulsions prepared with higher pressures showed stronger flavor release rates, while additional salvia dropped the release rate for ethyl acetate at pH 3.5. The physicochemical properties of flavour compounds, saliva addition and pH of emulsions influenced flavour release more than homogenization pressures. The potential in using nano-emulsions in food applications an be attributed higher stability and enhanced flavor release.

Salt and Aroma Compound Distributions Influence Flavour Release and Temporal Perception While Eating Hot-Served Flans.

To counteract the negative effect of salt overconsumption on health, strategies have been developed to reduce the salt content in food products. Among them, two promising strategies based on odour-induced saltiness enhancement and the heterogeneous distribution of flavour compounds were combined and assessed in four-layer cream-based snacks. To investigate the relationship between saltiness enhancement, temporal release and perception of flavour compounds in hot snacks with heterogeneous distribution of salt and aroma compounds, complementary techniques were used: nose space PTR-Tof-MS (Proton Transfer Reaction-Time of Flight-Mass Spectrometry) to assess the release of aroma compounds in vivo, and ATI (Alternate Time-Intensity) and TDS Temporal Dominance of Sensations) to evaluate perception as a function of time. The obtained results confirmed that the strategy of concentrating salt in the outer layer of a multilayer product was the optimal solution with respect to taste intensity. Heterogeneous salt distribution decreased aroma compound release and consequently aroma intensity but in different ways according to both salt and added aroma distribution in the food matrix. The salty taste enhancement could be due to the initial strong dominance of the salty sensation at the very beginning of the eating process. The involved mechanisms rely on a combination of physico-chemical and perceptual effects which are not clear yet.

The degree of substitution of OSA-modified starch affects the retention and release of encapsulated mint flavour.

This study explored the effect of the degree of substitution (DS) of octenyl succinic anhydride (OSA)-modified starch on the retention and release properties of spray-dried mint flavour microcapsules. The results showed that a higher DS (0.0287, 0.0379) led to greater flavour retention (86.68 %, 90.10 %). The flavour release was negatively correlated with DS during simulated oral processing. A mechanism by which DS affects flavour release was proposed. The emulsifying capacity was improved with increasing DS, thus forming an effective interface. The effective interface increased the partition coefficient, thereby reducing the release. During oral processing, a lower friction coefficient and higher microstructural stability and carrier enzymatic resistance jointly promoted interface stabilization. Data obtained using the EPI suite, a gas chromatograph, a mini traction machine, a Mastersizer analyser and confocal scanning laser microscopy validated this mechanism. This study provides a strategy for designing flavour microcapsules with high retention and slow-release properties using OSA-modified starch.

Mechanisms explaining the role of viscosity and post-deglutitive pharyngeal residue on in vivo aroma release: A combined experimental and modeling study.

The objective of this study was to analyse the viscosity effect of liquid Newtonian products on aroma release, taking human physiological characteristics into account. In vivo release of diacetyl from glucose syrup solutions varying widely in viscosity (from 0.7 to 405mPas) was assessed by five panelists using Proton Transfer Reaction Mass Spectrometry (PTR-MS). The physicochemical properties of the solutions and the physiological parameters of subjects were experimentally measured. In parallel, a mechanistic model describing aroma release while eating a liquid food was developed. Model predictions based on the characteristics of the glucose syrup solution were invalidated when compared to in vivo measurements. Therefore, the assumption that the post-deglutitive pharyngeal residue was considerably diluted with saliva was introduced into the model. Under this hypothesis, the model gives a satisfactory prediction of the in vivo data. Thus, relevant properties to be considered for in vivo release were those of product-saliva mixes.

Reducing sugar and aroma in a confectionery gel without compromising flavour through addition of air inclusions.

Sugar plays an important role in both the flavour and structure of confectionery. Targets have been set to reduce sugar; however, common strategies often result in changes in flavour and consumer rejection. In this study, an approach was developed to reduce sugar in confectionery gels by aeration, without significantly affecting perceived chewiness. Gelatine based gels with a 23% and 38% reduction in density were formulated using aeration. Mean bubble size was consistent across all gels (0.05-0.06 mm). Time-intensity sensory evaluation was carried out by a trained sensory panel (n = 10). With aeration, no significant difference in overall flavour perception was observed in the 23% and 38% reduced sugar and aroma gels. Air inclusions create a greater surface area, therefore accelerating mass transfer of volatiles and release of sucrose at the food-saliva interface. Consequently, we propose that less calorie dense products can be produced without compromising flavour by using gel aeration technologies.

Ethnicity, gender and physiological parameters: Their effect on in vivo flavour release and perception during chewing gum consumption.

In this study, the impact of physiological parameters, ethnicity and gender on flavour perception and flavour release of chewing gum was investigated. Proton Transfer Reaction Mass Spectrometry in-nose monitoring of volatile organic compounds was coupled to discontinuous time intensity sensory evaluation for mint flavour and sweetness perception. Each of the 29 subjects, 14 European and 15 Chinese panelists (13 male and 16 females, age 24 ±â€¯1.4 years old) consumed the samples in triplicates. Physiological parameters (oral cavity volume, salivary flow, acetone and isoprene concentration and fungiform papillae density) were measured. Significant differences for in vivo flavour release between Chinese and European panelists after 90 s of consumption and after the gum was removed from the mouth were found. Significant differences were observed also in flavour and sweetness perception while no gender effect was detected. In this work, for the first time an effect of ethnicity on in-nose flavour release monitored through PTR-MS was noticed during chewing gum consumption, in agreement with the findings from sensory evaluation. Single physiological parameters do not explain the relation between flavour in nose release and perception during consumption.

Influence of serving temperature on flavour perception and release of Bourbon Caturra coffee.

The present study aimed to investigate coffee flavour perception and release as function of serving temperature to support standardisation in the specialty coffee branch. The coffee cultivar Bourbon Caturra was evaluated at six serving temperatures ranging from 31°C to 62°C. Coffee samples were analysed by dynamic headspace sampling gas chromatography-mass spectrometry and descriptive analyses using sip-and-spit tasting. The release of volatiles followed mostly the van't Hoff principle and was exuberated at temperatures above 40°C. Aliphatic ketones, alkylpyrazines, some furans and pyridines increased most notably at temperatures ⩾50°C. The changes in volatile release profiles could explain some of the sensory differences observed. The flavour notes of 'sour', 'tobacco' and 'sweet' were mostly associated with the coffees served at 31-44°C, whereas coffees served between 50°C and 62°C exhibited stronger 'overall intensity', 'roasted' flavour and 'bitter' notes.

Investigating the in-vitro and in-vivo flavour release from 21 fresh-cut apples.

In-vitro and in-vivo flavour release from 21 different apple cultivars was studied using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) with a focus on the relationship between texture and volatile organic compound (VOC) emission. Generally, firm-juicy cultivars had a shorter time to first swallow (Tswal) and a higher number of swallows (Nswal), while softer-mealy cultivars had a longer Tswal and a lower Nswal. Firm-juicy cultivars containing high VOC concentrations had a short time to maximum intensity (Tmax) owing to a shorter Tswal and a higher Nswal as juice was released during mastication. Swallowing increased VOC flow through the nasal cavity. These results differ from previous flavour release studies with gel/gel-like model systems as juiciness/release of fluids is not a factor in such matrices. The current study, therefore, highlights the benefits of using in-vivo analysis to gain a better understanding of flavour release in real food products.

An atmospheric pressure chemical ionization-ion-trap mass spectrometer for the on-line analysis of volatile compounds in foods: a tool for linking aroma release to aroma perception.

An atmospheric pressure chemical ionization ion-trap mass spectrometer was set up for the on-line analysis of aroma compounds. This instrument, which has been successfully employed for some years in several in vitro and in vivo flavour release studies, is described for the first time in detail. The ion source was fashioned from polyether ether ketone and operated at ambient pressure and temperature making use of a discharge corona pin facing coaxially the capillary ion entrance of the ion-trap mass spectrometer. Linear dynamic ranges (LDR), limits of detection (LOD) and other analytical characteristics have been re-evaluated. LDRs and LODs have been found fully compatible with the concentrations of aroma compounds commonly found in foods. Thus, detection limits have been found in the low ppt range for common flavouring aroma compounds (for example 5.3 ppt (0.82 ppbV) for ethyl hexanoate and 4.8 ppt (1.0 ppbV) for 2,5-dimethylpyrazine). This makes the instrument applicable for in vitro and in vivo aroma release investigations. The use of dynamic sensory techniques such as the temporal dominance of sensations (TDS) method conducted simultaneously with in vivo aroma release measurements allowed to get some new insights in the link between flavour release and flavour perception.