The physical ageing characteristics of glucose, fructose, and their mixtures were studied using standard differential scanning calorimetry (DSC). The inflection, onset, midpoint,half-height, and endpoint glass transition temperature (Tg), fictive temperature (Tf), and relaxation enthalpy (
H) were measured as a function of ageing time. The relationship between
H and Tf was evaluated. The time dependence of
H was fit using the Cowie and Ferguson model. The ageing rate was expressed in terms of the average relaxation time (<>) and the entropy production (P). It was found that the fructose component decreased the rate of ageing of the mixtures.
Authors:Pham Anh Son, Shun Nishimura, and Kohki Ebitani
conditions as follows: dehydration of fructose to LA over LZY zeolite [ 9 ] and dehydration of glucose by Y zeolite [ 10 , 11 ] at temperatures between 383–433 K for 8–15 h gave yields of LA around 40% with a low yield of HMF (ca. 4%). ZRP zeolites with
Authors:József Szabó, Gergely Maróti, Norbert Solymosi, Emese Andrásofszky, Tamás Tuboly, András Bersényi, Geza Bruckner, and István Hullár
to sedentary lifestyle, the consumption of foods of high energy density and the extensive use of high-fructose sweeteners. An increasing number of evidences suggest that, among other nutritional factors, high fructose consumption may play a
Authors:Bohumil Bielik, Ladislav Molnár, Vladimír Vrabec, Romana Andrášiová, Ivana Cingel'ová Maruščáková, Radomíra Nemcová, Juraj Toporčák, and Dagmar Mudroňová
-fructose, maltodextrin, and maltose; Sigma–Aldrich, USA) was used for biofilm assay. A modified version of the previously described method ( O'Toole et al., 1999 ) was used to test biofilm formation. Fifty µL of bacterial suspension (McFarland standard 1
Authors:Katalin Badak-Kerti, Szabina Németh, Andreas Zitek, and Ferenc Firtha
In our research marzipan samples of different sugar to almond paste ratios (1:1, 2:1, 3:1) were stored at 17 °C. Reducing sugar content was measured by analytical method, texture analysis was done by penetrometry, electric characteristics were measured by conductometry and hyperspectral images were taken 6–8 times during the 16 days of storage. For statistical analyses (discriminant analysis, principal component analysis) SPSS program was used.
According to our findings with the hyperspectral analysis technique, it is possible to identify how long the samples were stored (after production), and to which class (ratio of sugar to almond) the sample belonged. The main wavelengths which gave the best discrimination results among the days of storage were between 960 and 1100 nm. The type of the marzipan was easy to distinguish with the hyperspectral data; the biggest differences were observed at 1200 and 1400 nm, which are connected to the first overtone of C-H bound, therefore correlate with the oil content. The spatial distribution of penetrometric, electric and spectral properties were also characteristic to fructose content.
The fructose content of marzipan is difficult to measure by usual optical ways (polarimetry, spectroscopy), but since fructose is hygroscopic, the spatial distribution of spectral properties can be characteristic.
The aim of dogrose breeding for fruit purposes is to select genotypes suitable for cultivation and to produce new genotypes by crossing. Physical and chemical analyses, prospective genotypes have been developed from
R. corymbifera, R. rubiginosa
varieties.In the course of the investigations, the highest vitamin C content was found in the hips of
. The glucose and fructose contents ranged from 9.57–13.36 g/100 g, averaged over several years. The amounts of these two carbohydrates were equal, or in some taxa (e.g.
R. corymbifera, R. canina
Sz3) the fructose content was higher.The glucose, fructose and vitamin C contents changed at different rates in each taxon during ripening. The results showed that the fructose content reached its peak a week earlier than the glucose content. The vitamin C content of morphological varieties of
did not change substantially during ripening.
The hydrothermal degradation was examined using D-(U-14C) glucose and D-(U-14C) fructose. By thin layer chromatography with methylene chloride, tetrahydrofuran (THF), acetic acid −60∶20∶20 as a mobile
phase it was, possible to separate and identify the carbohydrates and their reaction products, glyceraldehyde, dihydroxyacetone,
methylglyoxal, glycolaldehyde, 5-hydroxymethylfurfural and furfural. Up to 99% of the initial activity was determined by scintillation
counting of the TL-chromatograms. A reaction scheme for the hydrothermal degradation of glucose and fructose was obtained
from these results.