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A perfect linear correlation was found for methylglyoxal levels in 61 samples of Manuka honey, ranging from 189 to 835 mg/kg, and the corresponding antibacterial activities of the samples, which were between 12.4% and 30.9% equivalent phenol concentration. This clearly underlines that methylglyoxal is the dominant bioactive compound in Manuka honey and above concentrations of around 150 mg/kg directly responsible for the characteristic antibacterial properties of Manuka honey. Methylglyoxal can be a suitable tool for labelling the unique bioactivity of Manuka honey.

The changes were studied in microbiological, chemical, and sensory properties of Pacific oysters stored at 10°C, 5°C, and 0°C. Pseudomonas (22%) and Vibrionaceae (20%) species were dominant in raw oysters. The dominant bacteria found in the spoiled samples were Pseudomonas regardless of the storage temperature. During storage, rapid increases in aerobic plate count (APC) values of the samples stored at 10°C and 5°C were observed, while no obvious lag phases were detected. With the samples stored at 0°C, a decrease in APC value during the first 4 days and a lag phase of about 6 days were observed. The APC values of the samples stored at 10°C, 5°C, and 0°C reached the level of 10⁷ CFU/g on day 6, 10, and 18, respectively. All the tested samples stored at different temperatures revealed a slight decrease in pH and a significant increase of total volatile basic nitrogen (TVB-N) during storage. The average TVB-N concentration of about 22.0 mg N/100 g was observed at the end of the shelf-life as determined by APC. Combined with the sensory assessments, the shelf-life of 6-7, 10-11, and 17-18 days for oysters stored at 10°C, 5°C, and 0°C, respectively, was determined.

Furan and its derivatives were identified in a small number of heat-treated foods back in the 60's and 70's. In May 2004, US Food and Drug Administration published a report on the occurrence of parent furan in a number of thermally treated foods. Since furan has been classified as "possibly carcinogenic to human" by IARC, a great concern has been addressed to the analysis of this substance naturally-occurring in food. This paper gives a short overview on the mechanistic pathways of the parent furan formation in food by degradation of amino acids and/or reducing sugars, and oxidation of ascorbic acid and poly-unsaturated acids which can be induced by thermal or irradiation treatments; further, it deals with the metabolism and toxicology of furan as well as with the comparison of the methods of furan determination.

Industrial wine yeasts Saccharomyces bayanus and two interspecies hybrids (S. cerevisiae × S. bayanus) were checked for their suitability for fermentation of apple musts with different L-malic acid content (4, 7 and 11 g/l). The fermentation profiles including main organic acids, acetaldehyde, diacetyl, glycerol, esters and polyphenols were presented. The results were obtained by HPLC method (organic acids, acetaldehyde, glycerol, diacetyl), GC (esters), colorimetrically (polyphenols) and enzymatically (L-malic acid, ethanol). Although the fermentation profiles of wines were characteristic for specific yeast strains, similarities in organic acid profiles of wines fermented by S. bayanus and its hybrid S-779/25 were noted. In all the tested wines L-malic, pyruvic and citric acids were dominant. Statistical analysis of all wine parameters indicates that yeast strains respond individually to different acidities of the fermentation environment. In order to choose the right yeast strain for the fermentation of acidic musts, information about fermentation profiles should be included in the collection certificate of yeast strains.

A total of 30 tea samples of different origins, thirteen green tea samples, thirteen black tea samples, two semi-fermented tea samples and one white tea, imported to the Czech Republic, were collected and analysed for the total content of copper, iron, manganese, and zinc in tea leaves and tea infusions. The total contents of metals in tea leaves differ according to the type of tea (green or black) and are probably influenced by many other factors, e.g. soil properties. The total contents of Mn were much higher compared to the total contents of Cu, Fe, and Zn, and varied between 511-2220 mg/kg. To compare easily hot water soluble concentrations of Cu, Fe, Mn and Zn, 5 min, 60 min, and 24 h infusions were prepared. The extractability of the elements was in the order Cu > Zn > Mn > Fe. The proportions of the element contents in the infusion related to the respective total contents in leaves were 30 ± 16% Cu, 26 ± 10% Zn, 18 ± 10% Mn, and 1.5 ± 0.8% Fe, respectively. The results confirmed that tea infusion can be an important dietary source of Mn.

Phthalic acid esters (PAEs) rank among the primary risk pollutants and their adverse effects may endanger the environmental balance and affect the ontogenetic development of live organisms and their body functions. Therefore, the aim of this study was to monitor the occurrence of PAEs in packaging materials and plastics (infusion sets), to evaluate the accumulation and distribution of the most common phthalates such as DEHP (di-2-ethylhexyl phthalate) and DBP (di-n-butyl phthalate) in body tissues and organs of pigs and broiler chicks having been administered the phthalates per os, to assess the occurrence of PAEs in pig and cattle farms in the district of Hodonín (1997-1999), and to propose precautionary measures to mitigate the risk of PAE penetration into the food chain and the environments. DEHP and DBP contents in packaging materials ranged from 0.1 to 4259 mg DEHP, and from 0.1 to 1298 mg DBP per 1 kg printed packaging material, respectively. In haemodialysis patients, over 0.5 mg DEHP per 1 kg blood was found after three hours of haemodialysis. In combined feeds for farm animals (pigs, cattle, poultry), DEHP and DBP concentrations ranging from 0.07 to 1.77 and from 0.06 to 2.36 mg/kg feed, respectively, were detected. In all the food samples investigated, measurable levels of DEHP (less than 0.01-0.22 mg/kgsample) and DBP (less than 0.01 to 1.31 mg/kgsample) were found. In the experimental pigs and broilers, phthalates were distributed in all the organs monitored and the highest accumulation was found in adipose tissue as expected. All the samples withdrawn from farms in the Hodonín district had measurable phthalate concentrations; the hygienic limit (4 mg/kg) was exceeded in 2 samples of swine adipose tissue (4.26 and 6.92 mg/kgfresh sample) and in 1 sample of cattle adipose tissue (4.75 mg/kgfresh sample).

Certain physicochemical and sensory characteristics of the flavoured kefir drink were studied during refrigerated storage. Kefir drink batches were prepared using 2% addition of kefir grains, incubation for 18 h and subsequent filtration. The batches were then flavoured with blackberry, raspberry and strawberry aromas in the concentrations of 0.05, 0.10 and 0.15%, respectively. The samples were taken for analysis on 1^st, 4^th, 7^th, and 10^th days of storage at 4 ± 1°C. The sensory analysis of the flavoured kefir samples revealed the best acceptability level on the 4^th day of storage. Nevertheless, the samples were acceptable all throughout the storage. The percentage of the aroma addition significantly influenced the odour, flavour, texture, and mouth-feel, and the overall acceptability ratings. The higher percentage of the added aroma the more sensed, however, the lowest aroma addition was preferable. The pHs of the flavoured kefir drinks decreased throughout the storage time whereas, the titratable acidity, alcohol content and CO₂ values increased.

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.

This study was carried out to determine the influence of goat and cow milk fermented by Bifidobacterium longum Bb-46 on the pathogenic Salmonella enteritidis D strain. The basic hypothesis of this study was that fermented goat milk could possibly have a stronger inhibitory effect on the growth of Salmonella enteritidis D than fermented cow milk. The correlation between the inhibitory effect and some fermentation parameters (number of viable cells of Bifidobacterium longum Bb-46 and pH of fermented milk) was also analysed. S enteritidis D strains were isolated directly from the faeces of an infant with diagnosed salmonellosis. The inhibitory effects of goat and cow milk fermented with Bifidobacterium longum Bb-46 were determined on Salmonella-Shigella agar after 0, 5, 10, 15, 20, and 25 h from the start of fermentation. Bifidobacterium longum Bb-46 count and pH values were also measured in samples of goat and cow milk during fermentation. The results obtained have shown a considerably higher inhibitory effect of fermented goat milk on the growth of Salmonella enteritidis D as compared to that of fermented cow milk. At the same time, higher acidity and CFU of Bifidobacterium longum Bb-46 were noted in fermented goat milk in all the phases of the fermentation process. The inhibitory effects of the fermented goat and cow milk on Salmonella enteritidis D growth increased rapidly with the fermentation time. The results indicated high sensitivity of Salmonella enteritidis D to acidity of both fermented milks. Consequently, a significant correlation between the inhibition degree and pH values of fermented goat and cow milk was noted.

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.

The aim of this study was to investigate the contamination of beer of Slovak origin with fumonisins. A suitable analytical procedure was suggested - the limit of detection at the level close to 1 µg/l was achieved for both fumonisins B₁ and B₂. The recovery was determined at 93% for fumonisin B₁ and at 78% for fumonisin B₂. Fluorescence detection was used after derivatisation with a mixture of o-phthaldialdehyde and 2-mercaptoethanol. Phosphate buffer usually applied resulted in a poor separation of derivatised fumonisins. Peak splitting was observed depending on the pH of the eluent. The pH value of 2.6 was found suitable for the peak splitting elimination. A convenient gradient elution metod was suggested avoiding the possible interference in fumonisin contents determination. For the preparation of samples, immunoaffinity cleaning procedure was applied. Beer samples from all domestic producers were analysed. The content of fumonisins determined was under the limit of detection in all cases. All the beers tested were produced from the barley grown in 2003.

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.

Bakery characteristics of wheat dough and the final product and their predictability by NIR technique was investigated using 231 variety and commercial wheat samples (crop years 2003-2005). The behaviour of doughs was assessed with Brabender maturograph and OTG (Germany), the final product quality was evaluated by the baking test and image analysis. NIR spectra of flours were acquired on a NIRSystem 6500 spectrometer. Calibration equations for the selected rheological characteristics were computed by WINISI II using mPLS regression. The quality of prediction was evaluated by means of coefficients of correlation between measured and predicted values from cross and independent validation. A statistically significant dependence (with probability higher than 99%) was found with all rheological characteristics. The standard errors of cross-validation were achieved as follows: dough elasticity 16 BU, bread volume (11 min) 58 BU, specific loaf volume 34 cm³/100 g, bread cut area 2.6 cm^{2, penetration 4.1 mm, average cell area 0.4 mm2 and cells per cm2 7.4.}

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 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.

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.

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.

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.

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.

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.

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.

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.

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.

Long term experiments, which simulated storage of celery (Apium graveolens) under industrial (airconditioned store)/household (common cellar) conditions, were carried out. Several celery cultivars from both organic and/or conventional production were monitored for furanocoumarins levels for 16-26 weeks. The increase of furanocoumarin concentrations during the storage of all the tested celery cultivars was observed, nevertheless, the extent of toxicants accumulation differed among tested cultivars. The changes of furanocoumarin levels occurring during processing of vegetables were studied, too. Levels of both linear (psoralen, bergapten, xanthotoxin, trioxsalen, isopimpinellin) and angular (angelicin, sphondin, isobergapten) furanocoumarins in tested vegetable were determined by validated GC/MS (SIM) method. The detection limits (LODs) obtained by this analytical method were around 0.003 mg/kg.

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%.

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.

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.

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.

In this study, pathogenic strains of Y. enterocolitica were identified by microbiological and PCR methods. The samples were collected from pigs, cattle, poultry, and slaughter houses. Three common techniques were used to isolate Y. enterocolitica from the samples - ITC, PSB, and direct on the CIN. Primers A1/A2, Y1/Y2, and rfbC 1/rfbC 2 were used for the specific detection of the pathogenic strains of Y. enterocolitica. Traditional microbiological methods were found to be insufficient for the specific identification of the Y. enterocolitica pathogen. In comparison with PCR which was able to detect 149 strains, the biochemical test could detect only 138 species. These results show that the use of biochemical methods of cultivation did not allow the identification of all Y. enterocolitica pathogens. In total, 149 strains of pathogenic Y. enterocolitica were examined of which 120 were from pigs, 19 from poultry, 8 were cattle strains, and 2 came from the environments of slaughterhouses.