Czech Journal of Food Sciences, 2001 (vol. 19), issue 3
Antioxidant activity of 2,6-dimethyl-3,5-dialkoxycarbonyl-1,4-dihydropyridines in metal-ion catalyzed lipid peroxidation
G. Tirzitis, D. Tirzite, Z. Hyvonen
Czech J. Food Sci., 2001, 19(3):81-84 | DOI: 10.17221/6581-CJFS 
Antioxidants with 1,4-dihydropyridine structure were investigated as a less harmful alternative to synthetic phenolic antioxidants in liposomes under conditions simulating food storage. The antioxidant activities (AOA) of 2,6-dimethyl-3,5-dialkoxycarbonyl-1,4-dihydropyridines possessing various side chain length alkyls (CH3 - C16H33) in ester moiety were tested in transition metal-ion catalyzed liposome peroxidation and compared with AOA of Trolox™ and Probucol™. The compounds with C2H5 - C4H9 residues in the 3,5-position ester moieties exert the most pronounced...
The relationships between the chemical, dielectric and sensory properties of Edam cheese during ripening
I. Kubiš, I. Křivánek, S. Gajdůšek
Czech J. Food Sci., 2001, 19(3):85-89 | DOI: 10.17221/6582-CJFS
Proteolysis, dielectric properties and sensory data were measured during ripening of Edam type cheese (30% and 45% FDM). Cheese of different age (1-25 weeks) was analysed. Dielectric properties were used as a method for assessing proteolysis. Permitivity had significantly similar continuance as pH 4.4 total soluble N, both in opposite to sweet milky taste, during ripening period. This paper offers dielectric properties as useful characteristics for assessing proteolysis in cheese.
Mutagenic effects of selected trichothecene mycotoxins and their combinations with aflatoxin B1
P. Šmerák, I. Bárta, Z. Polívková, J. Bártová, M. Sedmíková
Czech J. Food Sci., 2001, 19(3):90-96 | DOI: 10.17221/6583-CJFS
The authors focused on the amplification of data on the mutagenicity of selected trichothecene mycotoxins (T-2 toxin, vomitoxin) and their combination with aflatoxin B1,which is known to be a strong mutagen. Mutagenic activity was investigated using the Ames test in a prokaryote model at low doses (close to 0.1 LD50). Whereas the individual trichothecene mycotoxins (T-2 toxin, vomitoxin) did not show any mutagenic activity in the test systems mentioned, in combination with AFB1, or as a combination of all three mycotoxins, they showed a mutagenic effect significantly greater than AFB1 alone in the Ames test...
Detection of olive oils authenticity by determination of their sterol content using LC/GC
I. Bohačenko, Z. Kopicová
Czech J. Food Sci., 2001, 19(3):97-103 | DOI: 10.17221/6584-CJFS
The content of selected sterols as declared in the EU Commission Regulation was used to prove the authenticity of olive oils. A modified method using the preparative LC with silica gel packed column and gradient elution with three mixtures of hexane and diethyl ether was used to separate undesirable interfering compounds in the unsaponifiable fraction before the determination of sterols using GC. Model experiments based on the determination of D-7-stigmastenol and campesterol (addition of sunflower and soybean oils), or brassicasterol (addition of rapeseed oil) were used to verify that this method is capable of identifying adulteration of olive oils...
Extract from Silybum marianum as a nutraceutical: a double-blind placebo-controlled study in healthy young men
V. Šimánek, N. Škottová, J. Bartek, J. Psotová, P. Kosina, L. Balejová, J. Ulrichová
Czech J. Food Sci., 2001, 19(3):106-110 | DOI: 10.17221/6585-CJFS
In a randomized, double-blind, placebo-controlled study, the effect of an extract from Silybum marianum seeds (ESM, milk thistle extract) on lipid and liver parameters and the antioxidant capacity of serum was investigated in 29 healthy men aged 18-32 years. They received either 858 mg of ESM (531 mg silymarin complex calculated on pure silibinin), or placebo, daily for the period of 60 days. No side effects were found. A routine biochemical analysis of the serum was performed as a measure of lipid and liver metabolism. Positive trend towards decreased serum cholesterol level and HDL-cholesterol increase was observed in the ESM group as compared...
Temperature profiles in microwave heated solid foods of slab geometry: Influence of process parameters
J. Houšová, K. Hoke
Czech J. Food Sci., 2001, 19(3):111-120 | DOI: 10.17221/6586-CJFS
A simple 1-D mathematical model for prediction of local temperatures in a layer of solid material during microwave heating (Houšová et al. 1998) and a sensitivity analysis were used to evaluate the influence of process and material parameters on vertical temperature profiles in a layer of material during heating. The results of calculations are presented in graphs and discussed. The incident microwave power and heat capacity and density of heated material are parameters with great effect on all local and average temperatures and local and average heating rates. The shape of temperature profile is influenced only to a small extent by a change...