Czech Journal of Food Sciences, 2003 (vol. 21), issue 5
3-Chloropropane-1,2-diol in models simulating processed foods: Precursors and agents causing its decomposition
J. Velíšek, P. Calta, C. Crews, S. Hasnip, M. Doležal
Czech J. Food Sci., 2003, 21(5):153-161 | DOI: 10.17221/3493-CJFS 
Formation of 3-chloropropane-1,2-diol (3-MCPD) was studied in model mixtures consisting of sodium chloride and either glycerol or various lipids (phospholipids, monoacylglycerols, diacylglycerols, triacylglycerols) derived mainly from palmitic and oleic acids. The average amount of 3-MCPD formed from these precursors after 30 min of heating at 200°C was from 9.7 (lecithin), to 5.1 (diacylglycerols), 4.7 (glycerol), 3.1 (triacylglycerols), and 2.9 (monoacylglycerols) µmol/mol, respectively. The formation of 3-MCPD from glycerol (one of the major precursors) was also studied in the presence of glutathione, cysteine, disodium carbonate and sodium...
Preparation of N-alkylamides of highly methylated (HM) citrus pectin
A. Syntsya, J. Čpíková, M. Marounek, P. Mlčochová, L. Sihelková, P. Blafková, M. Tkadlecová, J. Havlíček
Czech J. Food Sci., 2003, 21(5):162-166 | DOI: 10.17221/3494-CJFS
N-Alkylamides of highly methylated (HM) citrus pectin (DM = 73%) were prepared using heterogeneous amino-de-alkoxylation (aminolysis) with five selected n-alkylamines. The reaction was carried out in N,N-dimethylformamide at 8°C (n-butylamine), 25°C (n-hexylamine), and 45°C (n-octylamine, n-dodecylamine and n-octadecylamine). All the derivatives were converted into acid forms by washing with acidic water-ethanol mixture. The products were analysed by organic elemental analysis, diffusion reflection FT-IR spectroscopy and by 13C CP/MAS NMR. Both FT-IR and NMR spectra indicate...
Liquid chromatographic determination of biogenic amines in a meat product during fermentation and long-term storage
D. Smělá, P. Pechová, T. Komprda, B. Klejdus, V. Kubáň
Czech J. Food Sci., 2003, 21(5):167-175 | DOI: 10.17221/3495-CJFS
Liquid chromatographic procedures employing two derivatisation reagents, dansylchloride and o-phthaldialdehyde (OPA), were compared and applied for the determination of biogenic amines in meat products during fermentation and long-term storage. Both methods give similar results in terms of the detection limits, repeatability, recovery, and accuracy. Secondary amines (spermine and spermidine) do not react with o-phthaldialdehyde thus only their LC determination after derivatisation with dansylchloride is possible. Their contents during fermentation and/or long-term storage are nearly constant or slightly decrease, thus their determination...
Changes of starch during microwave treatment of rice
J. Pinkrová, B. Hubáčková, P. Kadlec, J. Příhoda, Z. Bubník
Czech J. Food Sci., 2003, 21(5):176-184 | DOI: 10.17221/3496-CJFS
The properties of rice after microwave irradiation were evaluated by means of amylograph and enzymic determination of the total and the damaged starch. The content of the total starch was not affected by the immediate energy output used for irradiation but that of the damaged starch increased with microwave energy absorbed and the temperature of treatment, mainly at the moisture of 30% and the temperature of 100°C. The results of damaged starch determination are in accordance with the amylographic readings of changes at maximum viscosity. Amylographic characteristics suggest minimal changes resulting in MW treatment of rice at moisture below 23%.
Crystals in hard candies
I. Šmídová, J. Čopíková, M. Maryška, M.A. Coimbra
Czech J. Food Sci., 2003, 21(5):185-191 | DOI: 10.17221/3497-CJFS
The main purpose of the contribution presented here is the study of the glassy state and the presence of crystals in hard candies. Hard candies are non-chocolate sweets usually made of sucrose and glucose or of maltose syrup. They can also be made of alditols, used in sugar-free hard candies. In hard candies, carbohydrates or alditols are in amorphous state. Crystallisation in the glassy state of hard candies occurs as a result of a bad formulation, processing or storage and can be detrimental to the product quality. Differential scanning calorimetry was used to determine the glass transition temperature Tg and the amount of crystals....