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The work was aimed at the growth suppression of cultured listerias strains by cultured lactococci strains or commercial mesophilic cheese cultures during common cultivations in the model UHT milk system (0.5% w/w of milk fat content) at 30°C during 18 h aerobically. Milk was primarily fermented by lactococci at the level of 10⁸ CFU/ml and secondarily contaminated by listerias at the level of 10³ CFU/ml. The most intensive growth suppressions of both Listeria innocua (CCM 5884 or Ln-03) strains were caused by Lactococcus lactis subsp. lactis (LCC 416 or CHCC 2281) strains or DELVO-ADD® 100-X DSF cheese culture; the listerias growth reductions was from the level of 10³ CFU/ml to 10⁰ CFU/ml. Obtained results should be applied to dairy industry provided that HACCP, GHP and GMP systems must be observed.

The present study has been done in order to determine the risks inherent in the milk production in Turkey. For that objective, factors such as the milk yield, the gross revenues realised, and the price levels as reflected to the producer's benefits, have been taken into account. Upon the calculation of the measures for variables, fluctuations were found in the milk yield, prices, and gross revenues. Based on the hypothesis that the information possessed by the producer on the economic and technological developments is scarce and restrained, the variable coefficient has been calculated as 10.81% for yield, 23.26% for prices, and 30.01% for gross revenues, respectively. With the hypothesis that the producers are aware of and informed on the economic and technological developments, these ratios, that is to say, the fortuitous variable coefficients would be, respectively, 2.07%, 15.96%, and 16.07%. According to the conclusions reached, an environment in which the producers can take rational decisions concerning the milk production can be said not to exist. For this reason, the government intervention through efficient measures for the dairy production will be necessary. Furthermore, the producers should be given informational support through the published studies in the agricultural extension.

Fluorescent Maillard compounds measurement provides more specific information on the extent of the Maillard reaction than other unspecific tools to monitor the reaction, and is suitable, as the first approach, to assess the nutritional quality of foods as related to protein damage. This work presents an optimised laboratory procedure for the measurement of total fluorescent intermediate compounds (FIC) associated with Maillard reaction, described and evaluated in a cereal-based product. Total FIC are evaluated using increased pronase E concentrations and different incubation times for the enzymatic hydrolysis, as well as three different sample clean-up steps after the enzymatic digestion. The effects of basic/acid media are considered for the stability of the fluorescent compounds. The standardised procedure is finally applied to breakfast cereals as a model of cereal-based products, analysing the correlation between total FIC production and fibre and protein contents. It is demonstrated that fluorescent compounds are mainly linked to the protein backbone in ready-to-eat breakfast cereals. Fluorescence measurement is presented as an inexpensive, rapid and accurate procedure to study the extent of Maillard reaction in breakfast cereals.

The microbiological quality of the final product and the safety of the production procedures were screened in an ice cream factory, after implementation of a Hazard Analysis Critical Control Points (HACCP) system. We analysed 30 vanilla (IC1), 30 strawberry (IC2), and 30 chocolate flavoured (IC3) samples of ice cream; 30 of water; 90 of personnel's hands flora; 150 of plastic ice cream containers flora; 50 of sanitised equipment-surfaces flora. After HACCP introduction, Staphylococcus aureus was not further detectable in ice cream and Escherichia coli was mostly less than 10 CFU/g, while the spoilage markers (total coliforms - TC, aerobic plate counts - APC) in ice cream and the environment were reduced by 20-35%. Mean log CFU/g, for IC1: TC from 2.20 reduced to 1.57, APC from 4.58 reduced to 3.62. For IC2: TC from 2.29 reduced to 1.65, APC from 4.61 reduced to 3.49. For IC3: TC from 2.67 reduced to 1.76, APC from 5.08 reduced to 3.81.

Effects of thermostable lipolytic enzymes Pseudomonas fluorescens 66 ZB in pasteurized milk on concentration of free fatty acids (VMK) in milk were studied in selected milk samples. Identical bulk milk samples were analysed by the method specified in previous papers (Vyletělová et al. 1999a, b, 2000). Reference milk samples (without bacterial strains) and the experimental ones (containing Ps. fl. 150 th. CFU/ml and 2800 th. CFU/ml, resp.) were stored at 6.5°C and 14°C and analysed at regular time intervals (24 h) - Table 1. An extractive-titric method (Kadlec et al. 1996; Table 2 and Fig. 2) was used for monitoring of fatty acid (MK) liberation. Precise analyses of MK and VMK were made by the chromatographic method (Figs. 1, 3 and 4). Medium-chain fatty acids (C12-C16) are liberated first of all; short-chain acids (C6-C10) were found sporadically or in very small quantities (Table 2). Dissociation constant of the specific fatty acid liberated from milk fat affects principally relationships between pH and free fatty acid concentration. The predominating proportion of long-chain acids in liberated fatty acid formation is associated with lower reduction of pH as compared to the predomination of fatty acids with shorter chains associated with more substantial reduction of pH. In our study, a rapid decrease of pH was noted before 168 h (Table 24); this corresponds to low concentrations of short-chain free fatty acids. Vyletělová et al. (2000) found significant relations between pH and contents of VMK (measured by the extractive-titric method); in some samples, correlation coefficients amounted to r = -0.93*** (P ≤ 0.001). The extractive-titric method analysing VMK concentrations (mmol/kg milk fat) provides results characterized by a systematic rise (e.g., 32.0 mmol/kg instead of 13.0 mmol/kg in raw milk). According to Kratochvíl (1992) 20 mmol VMK/kg milk fat signalized the starting point characterizing flavour degradation of milk caused by activities of fatty acids C12-C14 above all; the transformed value (respecting specifics of the extractive-titric method) amounts to 49 mmol/kg. In case of higher storage temperature a significant break is found after 144 h; in case of lower temperature this break is after 192 h (Table 2). Limits determining potential lipolytic modifications of milk flavour (RLZCHV) as related to specific samples and temperatures at VMK levels amounting to 49 mmol/kg or 20 mmol/kg are outlined in Fig. 2. Milk samples No. 5 and No. 6 stored at higher temperature surpassed this risk limit at 56 h and 64 h, respectively (Table 2, Fig. 2). On the contrary, milk samples stored temperatures corresponding to the standard storage temperature (storage of raw milk, transport, storage of pasteurized milk) surpass the mentioned risk level after 90 h and 140.5 h. Obtained results document the predominant role of storage temperature in the whole complex (production and processing of milk as a raw material or an intermediate product); evident differences in contamination rates (105 an 106) can be characterized as secondary effects in this case (Table 2). As related to practical conditions, the mentioned facts imply immediate processing of raw milk and pasteurized milk. This postulate must be respected namely by da

A wide array of antioxidative and anti-inflammatory substances derived from edible plants have been reported to possess chemopreventive and chemoprotective activities. Among the most extensively investigated and well-defined dietary chemopreventives is curcumin. Using the Ames test and in vivo micronucleus test, chemiluminescence test, blastic transformation test, and comet assay, we examined the antimutagenic effects of the chemically identified chemoprotective substance curcumin (diferuloylmethane) in the pure form on mutagenicity induced by three reference mutagens: aflatoxin B₁ (AFB₁), 2-amino-3-metylimidazo[4,5-f]quinoline (IQ), and N-nitroso-N-metylurea (MNU), and the effect of curcumin on the immunosuppression caused by these mutagens. Curcumin in the pure form showed a clear antimutagenic and immunomodulatory activities on mutagenicity and immunosuppression induced by reference mutagens.

A simple and rapid multiresidue method for the determination of nine banned synthetic dyes in various spices has been developed. Reversed phase HPLC coupled with mass spectrometry (tandem in time-ion trap mass analyser) was employed for the examination of crude acetonitrile extract acidified with acetic acid. The detection limits of Para Red, Sudan Orange G, Sudan I, Sudan II, Sudan III, Sudan IV, Sudan Red 7B and Rhodamine B were in the range of 0.02-0.1 mg/kg, the recoveries ranged from 75.7-92.3% with repeatability of 0.9-11.3%. Rather worse performance characteristics were obtained with Tropaeolin 000, obviously due to its more polar nature as compared to other dyes involved in this study. In spite of that, the developed method can be used for a reliable control of a wide range of dyes used for illegal colouring of various spices.

In this research, the growth and survival of E. coli O157:H7, Salmonella typhimurium and Staphylococcus aureus were investigated during kefir fermentation. Two different levels of inoculation of the strains were conducted; the levels of 102 CFU/ml (EC-1, SA-1 and S-1) and 103 CFU/ml (EC-2, SA-2 and S-2). At 0, 2, 6, 12, and 24 hours of kefir fermentation at 23 ± 1°C, samples were taken and the counts of E. coli O157:H7, S. typhimurium, and S. aureus were determined. EC-1 grew from 2.29 ± 0.02 log CFU/ml to 4.13 ± 0.18 log CFU/ml whereas EC-2 grew from 3.22 ± 0.04 log CFU/ml to 6.78 ± 0.99 log CFU/ml. Both S-1 and S-2 viable populations grew during the fermentation period, where sample S-1 grew from 2.37 ± 0.20 log CFU/ml to 4.64 ± 0.67 log CFU/ml and sample S-2 grew from 3.52 ± 0.07 log CFU/ml to 5.60 ± 0.10 log CFU/ml. SA-2 strains grew from 3.06 log CFU/ml to 3.64 log CFU/ml, SA-1 strains grew from 2.28 log CFU/ml to 2.66 log CFU/ml. According to the findings, E. coli O157:H7, S. typhimurium, and S. aureus can survive in kefir during fermentation.

The authors studied an extension of the sources of plant products for the diet in coeliac disease. This disease is induced by the components of glutenin proteins. In a collection of crops, they examined the contents of the total and protein nitrogen, the composition of protein fractions, the electrophoretic composition of reserve gluten and prolamine proteins, and the immunological determination of the gliadin amount using ELISA test. By immunological tests, gliadin content below 10 mg per 100 g of sample was found in the following species: amaranth (Amaranthus hypochondriacus and A. cruentus) followed by quinoa (Chenopodium quinoa), sorghum species - grain sorghum and sweet sorghum (Sorghum bicolor and S. saccharatum), millet (Panicum miliaceum), foxtail millet (Setaria italica ssp. maxima), broadrood (Digitaria sanguinalis) and buckwheat (Fagopyrum esculentum). These species can be considered as suitable for the diet in coeliac disease. Below-limit values were found in triticale (Triticosecale) and some oats varieties; this, however, will need some other tests. The analysed samples differred by the contents of crude protein and fraction structures of the protein complex. In pseudocereals amaranth, quinoa and buckwheat, the proportion of the soluble fractions of albumin and globulin was 50-65%. In grain sorghum, their proportion was 20.5%, in sweet sorghum 7.8%. In millet, foxtail millet, and broadrood, their proportion amounted to 12-13%. The proportion of prolamines was higher in sweet sorghum than in grain sorghum. Pseudocereals and millet contained 3-6% of prolamines, Italian millet 38.7%, and broadrood 23.1%, respectively. The two latter species had, however, lower contents of glutenins. In the other species studied, the contents of glutenins ranged from 12 to 22%. Electrophoretic analysis PAGE of prolamine proteins or SDS-PAGE ISTA, developed for gluten proteins, confirmed the results of immunological tests on the suitability of quinoa, grain sorghum, sweet sorghum, buckwheat, amaranth, broadrood, millet and foxtail millet for the diet in coeliac disease. These species did not contain prolamins or the content of -prolamins was negligible in the given samples. The tested species of wheat, triticale, and oats species were manifested as substandard or unhealthy for the diet.

Browning reactions of oxidised lipids with amino acids were studied in mixtures of refined soybean or rapeseed oil with alanine, valine, lysine, serine, cystine, cysteine, methionine, proline, and tryptophan. Oils were deposited in thin layers on cellulose fibres impregnated with the individual amino acids. The reaction proceeded in the dark, in dry air, at 50°C and at free access of oxygen. The browning determined at 430 nm followed a nearly zeroth order reaction without any induction period. The browning was very weak in the absence of amino acids, and all amino acids increased the browning rate, especially cysteine, methionine, and even more proline and tryptophan. The reaction rates were nearly the same in mixtures with rapeseed and soybean oils. Small amounts of hydroperoxides did not appreciably affect the browning rate. In the presence of copper ions, which belong to the most active catalysts of oxidation, the reaction rate was substantially higher. On the contrary, in the presence of antioxidants, the reaction rate was reduced to a marked degree but no induction period was observed. The probable main reaction mechanism was the reaction of lipid hydroperoxides, free radicals produced by their decomposition and/or unsaturated aldehydes under the formation of unsaturated imines which further polymerised into brown macromolecular substances.

We provide here for the first time the evidence that 3-chloropropane-1,2-diol (3-MCPD) occurs in foodstuffs in its free form and also in the form of esters with higher fatty acids. These esters represent a new class of food contaminants as 3-MCPD may be released in vivoby a lipase-catalysed hydrolysis reaction. We analysed 20 samples of selected retail food products for their free and bound 3-MCPD content. All samples contained free 3-MCPD at approximately 9.6-82.7 µg/kg food (3 replications, RSD = 0.4-7.0%). The levels of bound 3-MCPD (monoesters and diesters of 3-MCPD with higher fatty acids) found in the foodstuffs analysed varied between the LOD (1.1 mg per kg of fat) and 36.8 mg/kg fat with RSD = 0.3-3.3%. Five foodstuffs of plant origin processed at high temperatures contained elevated levels of bound 3-MCPD (0.14-6.10 mg/kg). A high level of bound 3-MCPD (0.28 mg/kg) was also found in a sample of pickled fish. Some variables potentially influencing the levels of either free or bound 3-MCPD in foodstuffs were determined (pH, water, chlorides, glycerol, fat and its components) and their significance was discussed.

Browning of stored food products, not exposed to heat treatment, is generally considered as a negative process. The formation of brown pigments at a temperature close to storage temperatures was followed in mixtures of either free fatty acids or vegetable oils with amino acids, deposited on cellulose fibres. The mixtures were studied at 50°C at free access of oxygen, and the browning process was monitored by reading the absorbance of brown products at 430 nm. Mixtures of free fatty acids and amino acids were turning brown in relation to their unsaturation degree. Mixtures of vegetable oils deposited on cellulose fibres were less coloured than if they were oxidized in presence of amino acids. The rate of browning increased with the degree of unsaturation in case of vegetable oils similarly as in case of free fatty acids. The browning degree was nearly the same in mixtures of oxidized fatty acids or vegetable oils with alanine, valine, lysine, serine or cystine, the browning was intermediate in mixtures with cysteine or methionine, but it was substantially more intensive in mixtures with proline or tryptophan. No significant difference was observed among different oils, but the discolouration was less rapid in case of low unsaturated peanut oil and more rapid in case of highly unsaturated linseed oil. The browning rate increased to a substantial degree with increasing cupric ion content, but decreased after addition of both synthetic and natural antioxidants, which decrease the oxidation rate.

Treatment with the water and tropical lemon juice extract powders from acerola fruit purees and leaves (100 mg/kg) significantly ameliorates the hepatic inflammatory responses such as increased serum levels of AST, ALT, and GGT in rats subjected to acute D-galactosamine (GalN) intoxication. The protective effects of their constituents could be related to their antioxidant activities to neutralise free radicals to attenuate hepatic lipid peroxidation and thus can protect liver damage. The effect of the water extract powder from fruit purees (100 mg/kg) was moderately stronger than that of ascorbic acid (10 mg/kg), but weaker than that of cyanidin-3-O-rhamnoglucoside (13.3 mg/kg). The water and lemon juice extract powders from Acerola fruit purees possess the 18.6 and 24.1-fold higher DPPH radical scavenging activities, respectively, than those from leaves, the higher so for those extracted with lemon juice than for those extracted with water. The vitamin C contents were much more higher in the extract powders from fruit purees compared with those from leaves. γ-Tocopherol predominated in the extract powders from fruit purees and α-tocopherol in those from leaves. Polyphenolic compounds were identified and analysed by GC/MS-SIM after acid hydrolysis, extraction and derivatisation to trimethylsilyl ethers.

Phytoestrogens represent biologically active compounds showing estrogenic activity similar to that of sex hormones - estrogens. Various adverse effects such as sterility, increase of females' genitals, lost of males' copulation activity, etc. were observed in farm animals after exposure to higher amounts of fodder containing phytoestrogens. On the other side, their presence in human diet is nowadays the object of many research studies concerned with prevention of breast and prostate cancer, osteoporosis and other hormone-linked diseases by dietary intake of phytoestrogens. Soya (Glycine max) is one of the main sources of these compounds in diet. Isoflavones daidzein and genistein occurring either free or bound in glycosides are the main phytoestrogens in this food crop. Coumesterol representing coumestans is another effective phytoestrogen contained in some eddible plants. In the first part of our study, analytical method for determination of free and total phytoestrogens was developed and validated. Following steps are included: (i) acid hydrolysis (only for "total phytoestrogens" analysis), (ii) extraction with methanol/water mixture, (iii) SPE preconcentration; (iv) identification/quantification using HPLC/DAD/FLD. The aim of present study was to document the fate of phytoestrogens and their forms during household/industrial processing. As documented in our experiments the most dynamic changes of phytoestrogen levels occur during soyabeans sprouting. High levels of coumestrol even exceeding other phytoestrogens were detected on this occasion.

Coffee acylglycerols hydrolysis and free fatty acids (FFA) oxidation reactions produce a FFA evolution that can affect to coffee quality during storage. The aim of this work was to study and to compare the FFA evolution of two ground roasted coffee samples: Brazilian Arabica 100% (A100) and Brazilian Arabica-India Cherry Robusta blend (A80:R20). Coffees were packaged under vacuum and stored at 25°C during 180 days. A significantly higher FFA initial concentration in A80:R20 coffee was observed. However, at 180 days, a higher increase of FFA concentration was shown in A100 sample. In conclusion, FFA oxidation seemed to be faster in A80:R20 blend than in A100.

In this work monoesters of sucrose and 􀑑-glucose with fatty acids (both even and odd) were prepared as pure substances using the direct selective esterification of free sugar with bulky acylating agent. This compounds were examined for their antibacterial activity (against Gram-positive bacteria) and antifungal activity.

The sources of reducing sugars and free asparagine of two different cracker products were identified, and acrylamide formation during baking was measured. The application of an asparaginase decreased the acrylamide content by at least 70% in both products. Replacing ammonium hydrogencarbonate by sodium hydrogencarbonate as baking agent and replacing reducing sugars by sucrose resulted in almost 80% less acrylamide in the wheat cracker. Decreasing free asparagine and reducing sugars in the ingredients and a lower end-temperature during baking lowered the acrylamide content of the potato cracker by about 50%.

Fat blends for manufacture of trans isomer-free emulsified fats are prepared by blending of 20-30% of structured fat with vegetable oil. Structured fats on the base of trisaturated triglycerides are produced by basic or enzymatic catalyzed transesterification of fully hydrogenated coconut oil with fully hydrogenated palmstearine or low erucic rapeseed oil. Physical properties of transesterificated structured fats produced by enzymatic reaction using immobilized sn-1,3 specific lipase Lipozyme TL IM or by randomization are similar. The replacement of palmitic acid with stearic acid without any changes in the ratio between medium chain FA and long chain FA was observed too. Fat blends contain mixture of β` and β crystals, the replacement of palmitic acid with stearic acid in structured fat does not influence neither crystalline modification nor SFC profiles but it has a significant effect on fat blend consistency.

Food raw materials and products contain inhibitors of oxidation reactions, both in the lipidic phase and the aqueous phase. The most important inhibitors are phenolic antioxidants. During food processing and storage, concentrations of antioxidants in the two phases reach an equilibrium. Phenolics react with lipidic free radicals, being converted into antioxidant free radicals, quinones, polymers and copolymers. Some degradation products possess an antioxidant activity, too. The relative antioxidant activity decreases with decreasing concentration of oxygen in the system and with increasing temperature. Antioxidants are more rapidly decomposed in surface layers. Health aspects of antioxidant degradation products are often neglected as the safety of antioxidant degradation products is mostly unknown.

The aim of our study was to investigate the influence of nutrition on the urinary excretion of Amadori products, pyrraline and pentosidine in a dietary study involving 18 healthy volunteers. Starting with day two, participants had to avoid Maillard product containing food for a period of 7 days, followed by day nine without dietary restrictions. Samples of 24 h-urine were collected and analysed for free furosine, pyrraline and pentosidine using dedicated chromatographic methods. For all MRPs, a significant decrease in the amount excreted with urine was observed due to the MRP-free diet. Urinary excretion of free pyrraline and fructoselysine, which was calculated from furosine analysis, were lowered about 90% from 3.9 ± 1.4 mg/d to 0.4 ± 0.3 mg/d and 7.2 ± 4.1 mg/d to 0.9 ± 0.2 mg/d, respectively. Urinary excretion of free pentosidine was only in the μg/d range and its decrease added up to 50% from 7.3 ± 3.7 μg/d to 3.4 ± 1.1 μg/d. These results indicate that renal excretion of MRPs is directly affected by dietary intake of those. With respect to the daily intake via heated foods, mainly as proteinbound derivatives, pyrraline seems to be of better bioavailability than the Amadori product and pentosidine. This points to different metabolic pathways. Whereas metabolic transformation of AGEs may quantitatively be of little importance, the major part of ingested Amadori products seems to be degraded in vivo.

A method based on the polymerase chain reaction (PCR) principle was validated for detecting cow's milk in goat and sheep cheeses. DNA was isolated from the cheeses using the isolation kit Invisorb Spin Food I by Invitek Co., designed for the samples of animal origin. The PCR method applied utilizes the sequence of the mitochondrial gene coding cytochrome b which is specific for mammals. It uses the common forward primer and the reverse primer species-specific. After electrophoresis, cow DNA was characterised by the fragment of the size of 274 bp, goat DNA by the fragment of 157 bp, and sheep DNA by the fragment of 331 bp. The detection limit of the PCR method described (1%) was determined with model samples made from pure goat cheese with a defined addition of cheese made from cow's milk. The method validated was applied in the analysis of 17 goat cheeses and 7 sheep cheeses obtained from retail trade. Products of Czech, Slovak, French, Dutch, and Italian origin were examined. The presence of undeclared cow's milk was detected in three kinds of goat cheese and in one of sheep cheese.

The factors important for the acrylamide formation in model systems were studied. The effects of two starch matrices (potato, wheat), the share of two monosaccharides (glucose and fructose) on the formation of acrylamide, and the impact of water addition were compared in model systems under isothermal conditions. Acrylamide was determined by GC/MS-NCI technique. The results showed that the water content is one of the most important factors in the formation of acrylamide, besides the reaction temperature and time. The minimum of acrylamide formation was observed at the water content between 25 and 40%; outside of this range, the acrylamide concentration was higher. The presence of starch reduced the amount of acrylamide formed from asparagine and saccharide, moreover, the effects of potato and wheat starches were similar. Fructose was more effective for the acrylamide formation in comparison with glucose. The combined contribution of glucose and fructose in the mixture with asparagine and starch to the acrylamide level corresponded to the sum of separate contributions of saccharides only at the middle content of added water.

This study was performed to determine the influence of fermented goat and cow milk produced by the use of Bifidobacterium longum Bb-46 on pathogenic Serratia marcescens and Campylobacter jejuni strains. The correlation between the inhibitory effect and some fermentation parameters (the number of viable probiotic cells and pH of fermented milk) was also determined. Bifidobacterium longum counts and pH values were also measured in milk samples during fermentation. The results showed that the inhibitory effect of Bifidobacterium longum Bb-46 fermented goat milk on Serratia marcescens increased with the fermentation time. The highest inhibitory effect of fermented cow milk occurred in the middle course of fermentation. Statistically significant correlation between the inhibition degree of Serratia marcescens growth and pH values of fermented goat milk was noted as opposed to the correlation between the inhibition degree of Serratia marcescens growth and pH values of fermented cow milk which was not statistically significant. All samples of goat and cow fermented milk exhibited inhibitory effects on the growth of Campylobacter jejuni.

Using the Ames bacterial mutagenicity test and an in vivo micronucleus test, we investigated the antigenotoxic effect of ellagic acid on the genotoxicity of three mutagens: amino-methylimidazo-quinoline (IQ), aflatoxin B1 (AFB1), and N-nitroso-N-methylurea (MNU). Ellagic acid is a naturally occurring phenolic compound which is found in a variety of soft fruits and vegetables. The effect of this compound on the immunosuppressive activity of mutagens was followed in vivo by the chemiluminescence test. In the Ames assay, ellagic acid at concentrations of 300 and 30 μg/plate demonstrably inhibits the mutagenic activity of two indirect mutagens: IQ and AFB1. The concentration of 300 μg/plate had the strongest effect on mutagenicity of all concentrations of IQ in strain TA98 of Salmonella typhimurium, whereas in strain TA100 concentration of 30 μg per dish of ellagic acid was more effective than 300 μg per plate. Also in combination with different concentrations of AFB1, ellagic acid proved to be a strong antimutagen. In this case the lower of the two effective concentrations - 30 μg/plate - had a much greater antimutagenic effect on both strains tested than 300 μg/plate. In combination with the direct mutagen MNU, ellagic acid did not show any marked antimutagenic effect at most of the concentrations tested in strain TA100. Only the highest concentrations of ellagic acid reduced the mutagenic effect of MNU weakly and only in combination with two lower concentrations of MNU. In the micronucleus test, three-day oral application of ellagic acid prior to the applicaton of AFB1, IQ, or MNU, respectively, markedly reduced the numbers of micronuclei induced by these three mutagens in polychromatophilic erythrocytes of mice. Chemiluminescence test with mouse granulocytes proved that ellagic acid not only prevents the inhibitory effects of mutagens on free oxygen radicals and hydrogen peroxide production, but that this production is stimulated by ellagic acid in combination with mutagens even to a greater extent than by ellagic acid alone. From these results we can deduce that ellagic acid repairs strong immunosuppressive effects of all mutagens applied.

Phenolic compounds were extracted with 80% methanol from caryopses and embryos of rye (cv. Dańkowskie Złote and Amilo). In all extracts, reducing power, scavenging effect on DPPH radical, and antioxidant activity in a β-carotene-linoleate model system were examined. The highest content of total phenolic compounds was noted in the extract from caryopses of Amilo (7.93 mg/g of extract). UV spectra of all extracts were characterised by maxima originated from phenolic acids (320, 326 and 328 nm), and by maxima at shorter wavelengths (272 and 274 nm) attributed to other phenolic compounds. All extracts showed a good antioxidant activity in a β-carotene-linoleate model system. This activity was similar to that reported before in leguminous seeds extracts. The antioxidant activities of the extracts from the caryopses of Dańkowskie Złote and the embryos of both cultivars were very similar, especially during the second part of the incubation period. The extract of Amilo embryos showed a slightly weaker antioxidative effect. The weak antiradical effects in the experiments with DPPH radical and a weak reducing power were characteristic for all the extracts investigated.

The antioxidative properties of aqueous plant extracts were evaluated using common methods such as the Rancimat and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) free radical method. Moreover, a voltammetric procedure based on the protective effect of antioxidants against the oxidative DNA damage was employed using a disposable DNA biosensor fabricated as a screen-printed electrode chemically modified by calf thymus double stranded (ds) DNA. The total polyphenols were also determined spectrophotometrically with the Folin-Ciocalteu agent. The extracts of oregano and lemon balm exhibited significantly higher activity than those of thyme and agrimony. The results were treated statistically and their operational character is discussed.

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 T_g and the amount of crystals. Polarising microscopy was used to show the undesirable presence of crystals in samples of hard candies. The carbohydrates composition of the samples was determined by HPLC and the moisture content in each sample was evaluated by Karl Fisher method.

A total of 60 random samples of fresh chicken burger, fillet, and luncheon (20 of each) were collected from markets at Tanta city. The average total yeast counts (cfu/g) in burger, fillet, and luncheon samples were 2.7 × 10⁶ ± 1.1 × 10⁶, 2.1 × 10⁵ ± 0.9 × 10⁵, and 1.4 × 10⁷ ± 0.7 × 10⁷, respectively. A total of 158 yeast isolates of 23 species were isolated and identified. Candida, Cryptococcus, Debaromyces, Issatchenkia, Pichia, Rhodotorula, Saccharomyces, Trichosporon and Yarrowia species were recovered from the examined samples of fresh chicken meat products in varying percentages ranging from 5% to 50%. The tested plant extracts of cinnamon, clove and thyme revealed a potent anti-yeast activity against C. albicans, D. hansenii and S. cerevisiae at 20% concentration, and a moderate inhibitory activity against these yeast strains at 10% concentration, while garlic extract had a lesser inhibitory effect on the yeast strains tested at the same concentration. Moreover, thyme, cinnamon and clove extracts had a complete inhibitory effect on chicken fillet inoculated with Candida albicans when incubated at 5°C and 25°C.

Ochratoxin A is a very common mycotoxin which can be found rather often, predominantly in various cereal materials and in products from this type of plants. Our aim was to apply an analytical procedure with a suitable detection level of ochratoxin A for its estimation in beer. The detection level of the method suggested was close to 0.001 µg/kg. The analytical procedure is based on HPLC separation with fluorescence detection. The application of this method is demonstrated and analytical results obtained with beer of domestic provenience are reported.