Identification of aroma compounds in a commonly prescribed oral nutritional supplement and associated changes in olfactory abilities with human ageing.

Undernutrition is prevalent in the older adult population. Oral nutritional supplements (ONS) are a clinically effective nutritional intervention, however, patient acceptance of ONS can be limited by their palatability. While sensory attributes such as sweetness and mouthfeel have been investigated, the contribution made by aroma to the perceived flavour of ONS has not been studied.

Understanding the lost functionality of ethanol in non-alcoholic beer using sensory evaluation, aroma release and molecular hydrodynamics.

Consumer sensory evaluation, aroma release analysis and biophysical protein analysis were used to investigate the effect of ethanol on the release and perception of flavour in beer (lager and stout) at different ethanol levels (0 and 5% ABV). Consumer study results showed no significant differences in orthonasal perception, yet retronasal results showed that 0% lager was perceived as maltier with reduced fruitiness, sweetness, fullness/body and alcohol warming sensation (p < 0.05).

Non-destructive characterisation of mesenchymal stem cell differentiation using LC-MS-based metabolite footprinting.

Bone regeneration is a complex biological process where major cellular changes take place to support the osteogenic differentiation of mesenchymal bone progenitors. To characterise these biological changes and better understand the pathways regulating the formation of mature bone cells, the metabolic profile of mesenchymal stem cell (MSC) differentiation in vitro has been assessed non-invasively during osteogenic (OS) treatment using a footprinting technique. Liquid chromatography (LC)-mass spectrometry (MS)-based metabolite profiling of the culture medium was carried out in parallel to mineral deposition and alkaline phosphatase activity which are two hallmarks of osteogenesis in vitro.

Bio-oil and bio-char from low temperature pyrolysis of spent grains using activated alumina.

The pyrolysis of wheat and barley spent grains resulting from bio-ethanol and beer production respectively was investigated at temperatures between 460 and 540 °C using an activated alumina bed. The results showed that the bio-oil yield and quality depend principally on the applied temperature where pyrolysis at 460 °C leaves a bio-oil with lower nitrogen content in comparison with the original spent grains and low oxygen content. The viscosity profile of the spent grains indicated that activated alumina could promote liquefaction and prevent charring of the structure between 400 and 460 °C.

Rapid analysis of formic acid, acetic acid, and furfural in pretreated wheat straw hydrolysates and ethanol in a bioethanol fermentation using atmospheric pressure chemical ionisation mass spectrometry.

Atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) offers advantages as a rapid analytical technique for the quantification of three biomass degradation products (acetic acid, formic acid and furfural) within pretreated wheat straw hydrolysates and the analysis of ethanol during fermentation. The data we obtained using APCI-MS correlated significantly with high-performance liquid chromatography analysis whilst offering the analyst minimal sample preparation and faster sample throughput.

Effect of fat content on flavor delivery during consumption: an in vivo model.

Data from studies of the effect of fat on in vivo flavor release were modeled to generate a predictive model (R(2) = 0.71). The data included a range of values from the literature and 200 new data points giving a total data set of 345 values; of these, 310 values were used as a data set for model development, and the remaining 35 values were used as a test set for model validation.

Differences in the effect of bolus weight on flavor release into the breath between low-fat and high-fat products.

The maximum intensity of flavor release increased as the weight of food introduced into the mouth (the bolus) was increased for a range of different foods. The relationship was not directly proportional (1:1) but followed a power law function. Low-fat (< or = 1 g/100 g) foods showed a different relationship than high-fat (> or = 5 g/100 g) foods, but all low-fat and all high-fat foods were broadly similar irrespective of food type or flavor molecule chemistry.

Temporal aroma delivery from milk systems containing 0-5% added fat, observed by free choice profiling, time intensity, and atmospheric pressure chemical ionization-mass spectrometry techniques.

A temporal aroma delivery from milk systems containing 0, 0.5, or 5% added fat and flavored with seven-component strawberry flavoring and linalool was observed by free choice profiling (FCP), time intensity (TI), and atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) techniques. A suppressing effect of fat on the volatility of the relatively nonpolar compound linalool was observed by all methods, but only slight evidence (with the TI method) of the effect of fat on the overall strawberry (based on more polar compounds) intensity was found.

LuxS: its role in central metabolism and the in vitro synthesis of 4-hydroxy-5-methyl-3(2H)-furanone.

Many bacteria produce extracellular molecules which function in cell-to-cell communication. One of these molecules, autoinducer 2 (AI-2), was first described as an extracellular signal produced by Vibrio harveyi to control luciferase expression. Subsequently, a number of bacteria have been shown to possess AI-2 activity in their culture supernatants, and bear the luxS gene product, which is required for AI-2 synthesis.

Retronasal transport of aroma compounds.

A comparison was made between the amounts of volatiles in the headspace above a solution and the breath volatile content (exhaled from the nose or mouth) after consumption of the same solution. The amounts of volatiles in the breath were lower than those in the headspace, with breath exhaled via the mouth containing, on average, 8-fold more volatiles than breath exhaled via the nose. Dilution of the sample by saliva in-mouth did not appear to be a major factor affecting volatile delivery.