| 1. |
- Niimi, Jun, et al.
(författare)
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Aroma-taste interactions between a model cheese aroma and five basic tastes in solution
- 2014
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Ingår i: Food Quality and Preference. - : Elsevier BV. - 0950-3293 .- 1873-6343. ; 31:1
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Tidskriftsartikel (refereegranskat)abstract
- The flavour perception of cheese results from complex sensory interactions between tastes and aromas. Using a model cheese solution, this study investigated perceived interactions between each of five basic tastes and a cheese aroma mixture containing ten volatile compounds commonly found in cheese. The five tastes - sucrose (sweetness), sodium chloride (NaCl) (saltiness), monosodium glutamate (MSG) (umami), lactic acid (sourness), and caffeine (bitterness) - were individually mixed with cheese aroma in water using a 5 taste level (0.2 log series) by 3 aroma level (0.5 log series) design. Aroma controls with no added taste were also included. This resulted in 18 samples for each single taste-aroma combination. An additional 18 samples were produced using a mixture of all 5 tastes with the 3 aroma levels. A panel of trained assessors (n=10) evaluated cheese flavour intensity and taste intensity using 100 point line scales. Evaluation was carried out in duplicate, with samples grouped by taste type; 1 evaluation session per taste per replicate. Within type, order of presentation was balanced, and taste type order was randomised between replicates. Cheese flavour intensity was enhanced by sucrose and NaCl, while being suppressed by lactic acid. NaCl enhanced cheese flavour intensity the most at high aroma level, while lactic acid suppressed the most at low aroma level. When MSG level was increased, cheese flavour intensity was enhanced at both low and medium aroma levels, but was suppressed at the high aroma level. The greatest enhancement of cheese flavour intensity was found with the mixture of 5 tastes. Aroma significantly enhanced umami and bitterness, but did not enhance sweetness, saltiness, or sourness. This study showed that the perceived interaction between taste and cheese aroma depended on taste type and on the concentration levels of both taste type and aroma. The mixture of tastes was more effective at enhancing cheese flavour intensity than single tastes. This study provides knowledge that will underpin further study of taste-aroma interactions in a model cheese that aims to optimise cheese flavour intensity and character.
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| 2. |
- Niimi, Jun, et al.
(författare)
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Cheddar cheese taste can be reconstructed in solution using basic tastes
- 2014
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Ingår i: International Dairy Journal. - : Elsevier BV. - 0958-6946 .- 1879-0143. ; 34:1, s. 116-124
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Tidskriftsartikel (refereegranskat)abstract
- The taste of cheese contributes to flavour character directly and by cross-modal interactions with aroma. However, the relative contribution of specific tastes, i.e., sweet, salt, umami, sour, and bitter, is not well understood. Twelve cheeses were profiled by a trained sensory panel and the five tastes shown to significantly differ in intensity. Sucrose, NaCl, monosodium glutamate, lactic acid, and caffeine were mixed in water and adjusted using a 25-1 fractional factorial design (FFD) to reconstruct cheese taste; the optimised construct was compared with a Cheddar cheese to measure similarity for each taste type. The FFD provided knowledge of taste-taste interactions and aided the reconstruction of the taste profile of Cheddar cheese in solution. The reconstructed cheese solution did not significantly differ in overall intensity, saltiness, sourness, umami, and bitterness from the Cheddar cheese based on chi-squared tests. Sweetness was a difficult attribute to adjust due to its relatively low intensity.
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| 3. |
- Finegan, Donal P., et al.
(författare)
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Spatial dynamics of lithiation and lithium plating during high-rate operation of graphite electrodes
- 2020
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Ingår i: Energy and Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 13:8, s. 2570-2584
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Tidskriftsartikel (refereegranskat)abstract
- The principal inhibitor of fast charging lithium ion cells is the graphite negative electrode, where favorable conditions for lithium plating occur at high charge rates, causing accelerated degradation and safety concerns. The local response of graphite, both at the electrode and particle level, when exposed to fast charging conditions of around 6C is not well understood. Consequently, the conditions that lead to the onset of lithium plating, as well as the local dynamics of lithium plating and stripping, have also remained elusive. Here, we use high-speed (100 Hz) pencil-beam X-ray diffraction to repeatedly raster along the depth of a 101 µm thick graphite electrode in 3 µm steps during fast (up to 6C) charge and discharge conditions. Consecutive depth profiles from separator to current collector were each captured in 0.5 seconds, giving an unprecedented spatial and temporal description of the state of the electrode and graphite's staging dynamics during high rate conditions. The electrode is preferentially activated near the separator, and the non-uniformity increases with rate and is influenced by free-energy barriers between graphite's lithiation stages. The onset of lithium plating and stripping was quantified, occurring only within the first 15 µm from the separator. The presence of lithium plating changed the behavior of the underlying graphite, such as causing co-existence of LiC6 and graphite in the fully discharged state. Finally, the staging behavior of graphite at different rates was quantified, revealing a high dependency on rate and drastic hysteresis between lithiation and delithiation.
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| 4. |
- Griffiths, P. C., et al.
(författare)
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Small-angle neutron scattering, electron paramagnetic resonance, electrophoretic NMR, and time-resolved fluorescence quenching studies of sodium dodecyl sulfate and tetra(ethylene oxide) dodecyl ether mixed surfactant micelles
- 2004
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Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 108:4, s. 1351-1356
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Tidskriftsartikel (refereegranskat)abstract
- Small-angle neutron scattering (SANS), time-resolved fluorescence quenching (TRFQ), electrophoretic NMR (ENMR), and electron paramagnetic resonance (EPR) have been used to study mixed micelles formed from the two dodecyl tailed surfactants, sodium dodecyl sulfate (SDS) and tetra(ethylene oxide) dodecyl ether. By combining the TRFQ and EPR techniques, one is essentially able to calculate the SANS data, lending significant weight to the micelle characteristics thus obtained. EPR reports the degree of hydration of the surfactant headgroups; TRFQ, the micelle aggregation number and inter alia the volume of the hydrophobic core. Given the physical dimensions of the surfactant, i.e., alkyl chain length, headgroup volumes, etc., it is then possible to calculate the micelle ellipticity and shell thickness. The ENMR studies provide a rather different but complementary estimate of the ionic character of the micelle. With increasing nonionic content, the aggregation number increases, the micelle becomes more elliptical, and the headgroup region of the micelle becomes less hydrated and significantly more viscous. The degree of sodium counterion dissociation shows an initial small decrease with decreasing SDS micelle mole fraction but subsequently increases, reflecting the interplay between the electrostatic character of the micelle surface and the micelle curvature.
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