Search results for "Sucrose solution"

Aroma Volatility from Aqueous Sucrose Solutions at Low and Subzero Temperatures

2004

International audience; The gas-liquid partition coefficients of ethyl acetate and ethyl hexanoate have been measured in water and aqueous sucrose solutions from 25 to -10 degrees C by dynamic headspace. Experiments were carried out on sucrose solutions at temperatures where no ice formation was possible. Results showed that when sucrose concentration increased, aroma volatility increased except for ethyl hexanoate and in the highest sucrose concentration solution (57.5%). A quasi-linear temperature decrease on aroma volatility was observed in sucrose solutions from 25 to around 4 and 0 degrees C. Then, from 0 to -10 degrees C, aroma volatility did not decrease: ethyl acetate volatility rem…

Water Dynamics in Biological Systems investigated using Neutron Scattering Techniques

Living systems can not survive in absence of the water environments which play a fundamental role in living functions. Thus in the scienti?c community many studies were and are addressed to characterize water and its dynamics properties in biological systems. However, a clear description of water in such systems has been not reached yet. In fact, the investigations performed with di?erent techniques - those based on Nuclear Magnetic Resonance or those based on Neutron Scattering - look at di?erent di?usive motions and interactions water-biomolecules, leading controversial results and hence generating many debates between scientists. In this thesis we support the idea that two water populati…

Foragers of the stingless bee Plebeia droryana inform nestmates about the direction, but not the distance to food sources

2020

The tropical stingless bees have evolved intricate communication systems to recruit nestmates to food locations. Some species are able to accurately communicate the location of food, whereas others simply announce the presence of food in the environment. Plebeia droryana is a tiny Neotropical stingless bee that, until recently, was thought to use a solitary foraging strategy, that is without the use of a recruitment communication system. However, recent research has indicated that P. droryana might be able to recruit nestmates to specific food source locations. We tested this by studying whether foragers can guide nestmates in the direction and the distance of artificial feeders placed in t…

Correlation between octopaminergic signalling and foraging task specialisation in honeybees

2020

Regulation of pollen and nectar foraging in honeybees is linked to differences in the sensitivity to the reward. Octopamine (OA) participates in the processing of reward-related information in the bee brain, being a candidate to mediate and modulate the division of labour among pollen and nectar foragers. Here we tested the hypothesis that OA affects the resource preferences of foragers. We first investigated whether oral administration of OA is involved in the transition from nectar to pollen foraging. We quantified the percentage of OA-treated bees that switched from a sucrose solution to a pollen feeder when the sugar concentration was decreased experimentally. We also evaluated if feedi…