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The roasting process allows complex chemical reactions in foods leading the formation of the Maillard-related compounds, which are of fundamental importance for colour and aroma development in hazelnuts (Corylus avellana L.). Colour is a charming characteristic of roasted foods; despite of their fundamental role in organoleptic properties, the roasting allows accumulation of some potentially toxic technological contaminants, as showed in other matrices (e.g. acrylamide, furan and D-amino acids). Free and protein-bound D-amino acids (D-aa) in foods can origin by technological processing (their formation is pH, time, and temperature-dependent), and also from bacterial racemases in fermented foods, as recently showed in cocoa ( FRIEDMAN 1999; CALIGIANI et al. 2007) So, these compounds can be used as thermal and bacterial markers. Racemisation impairs digestibility/nutritional quality of foods; some D-aa acids are both beneficial and deleterious (DA-WEN SUN 2008). The L*a*b* (international standard for colour measurements adopted by the Commission Internationale d'Eclairage, CIE, 1976) and Red Green Blue (RGB) systems are the most employed methods for colour analysis. Computer Vision Image Analysis (CVIA) coupled with Artificial Intelligence (AI) and related tools (Principal Component Analysis, Artificial Neural Networks, Self Organising Maps) should be considered a powerful approach for evaluating colour development in foods (PATZOLD & BRUCKNER 2006). First aim of our study was to monitor via GC-MS the D-aa formation in hazelnuts during different conditions of roasting. Second aim was to develop a CVIA/AI method to study the colour development in roasted hazelnut, considering the correlation between colour and D-aa too. The racemisation of L-aa (particularly D-aspartic acid plus D-asparagine, D-asx) in hazelnut was time-temperature dependent. Protein-bound D-asx (expressed as D/(L+D); 1.49%) and free D-ala (5.87%) were predominant in Infra-Red roasted samples. Hot-air flow process leads the formation of free-D-aa (D-ala: 6.77%; D-asx: 3.47%; D-glu: 4.50%). Using Back Propagation Neural Network on the Discrete Fourier Transform output (whole surface colour), the identification of hazelnuts samples roasted in different condition was achieved. Red colour decreased according to the correspondent increase of D-amino acids content. Concluding, CVIA/AI is a promising complex tool useful to simplify the comprehension of a complex model system, as colour development in roasted hazelnuts. Keywor

Inflammation in joint: The liberation of phospholipids from cell membranes represents the first step of inflammation cascade. By action of phospholipase A2 is split of the arachidonic acid. Free arachidonic acid is than metabolised by two enzymes: 5-lipooxygenase and 2-cyclooxygenase to generate the group of prostanoids and leukotrienes which are the first active proinflammation compounds, starting the whole proces of inflammation. We verífied, that 27 flavonoids and flavans, contained in American patent Univestin are really able to interrupt this pathway by inhibition both of those enzymes. All these flavonoids are naturally occurring chemicals, which give color to plants and are found in plants, fruits, grains, nuts and vegetables. Theirs antioxidant capacity eliminates the action of Cyt P450 also and prevents to origine of epoxides. Cancerogenesis: Inositolhexaphosphate (IP6) is found in substantial amounts in whole grains, cereals, legumes, nuts and seeds. As well as inositol, IP6 is contained in most mammalian cells, wherein they are important in regulating vital cellular function such as signal transduction, cell proliferation and differentation. Inositol and IP6 are contend in product Inocell and there is additional evidence that inositol alone may further enhance the anti-cancer effect of IP6. Beside decreasing cellular proliferation IP6 also causes differentation of malignant cells ofen resulting in a conversion to normal phenotype, what leads to starting of apoptose in those cells. Inocell greatly enhances NK cell activity, regulates cell growth and has very strong antioxidant capacity. The suggestion we can demonstrate on succesfful efects of Inocell in concrete causes of patients with various types of cancerogenesis. Peptic ulcer disease and gastric cancer: The ability of Vaccinium macrocarpon, the North American cranberry, to prevent bacterial adhesion has been used to advantage in the prevention of urinary tract infections and has recently been described for the prevention of adhesion of bacteria responsible for oral infections and stomach ulcers as well in Helicobacter pylori.

The work aimed to evaluate the state of agricultural soil contamination what is important for the gaining of information needed for growing of hygienic safe raw materials and foodstuffs. Metallic pollution of soil in Zemplínska polluted area has begins by accumulation of heavy metals in soil, mainly resulting from location in vicinity of chemical and industrial factories, as well as from many others sources. The pH value development indicates gradual trend of soils acidification, except of alkalic ones reaching up to 20% from total arable soils in Slovakia. Acidification is process, where acidity of abiotic compounds has been increased. Soil reaction is a significant agrochemical property markedly affecting growing and developing of plants, and has directly effect on soil fertility, influencing the ecological conditions for plants and soil microorganisms. The site had been localised with GPS and 5 sampling places had been fixed. From these sites the soil samples were taken from 1 depth, A horizon (0-0,2 m) and then processed and managed according to particular ISO norms. The soil reaction and the heavy metals contents in solution of aqua regia and HNO₃ in soil samples were assessed. Afterwards the gained results had been compared with limit values from legislative documents.

During thermal processing of foods non-volatile precursors undergo various types of reactions leading to the unique aromas of well-accepted product such as cocoa, coffee, cereals or nuts. It is without doubt that the reaction between free amino acids and carbohydrates or their degradation products, known as the Maillard reaction, is among the most important "flavor delivery" systems in such foods. However, studies using approaches of "molecular sensory science" have shown that the majority of the Maillard-type reaction products, identified so far, do not show a contribution to the aroma of processed foods. In addition, many of the key Maillard aroma compounds, such as 4-hydroxy-2,5-dimethyl-3(2H)-furanone, the Strecker aldehydes or various pyrazines were found to be identical in many processed foods. Using several foods as examples, the lecture is intended to show that the quantitative balance of potent Maillard-type flavor compounds is a key to explain the differences in the different aroma perception of thermally processed foods. In addition, the presence of lipid degradation products and/or single "character impact odorants" transferred from the raw materials into the final products have to be considered as "modifiers" of the overall "aroma orchestra".

Objective of this work was determination of processing contaminant known as 3-MCPD (3-chloropropane-1,2-diol) in its free and bound form in breads with defined parameters of processing. Selected and analysed were 24 samples, which represented two sets of breads produced in bakeries equipped with a continual line. In all cases determinations were carried out for breadcrumb and crust separately. The first set of samples were wheat-rye breads produced chronologically in ten days in the bakery Michelská pekárna, slightly different in temperatures and times of baking. The second set contained 14 samples of wheat-rye breads with a content of rye flour less than 40% differing in the yeast type and acidity. These breads were produced in the bakery Kontinua. The fat content was determined in all samples by Soxhlet extraction. Free and bound 3-MCPD was determined by gas chromatography-mass spectrometry method. Concentration of free 3-MCPD in samples was at interval < 9-54.5 μg/kg. Concentration of bound 3-MCPD was at interval 1.56-23.60 mg/kg of fat (i.e. 5.7-84.9 μg/kg of sample).

Printing inks contain many substances, the use of which is not allowed in food contact materials. Recently the migration of printing ink constituents from the printed packaging materials into food either through the packaging material or via the set-off phenomenon has been reported. The aim of presented study was to quantify the transfer of selected printing ink plasticisers, i.e. acetyl tributyl citrate (TBAC), bis(2-ethylhexyl) adipate (DEHA), bis(2-ethylhexyl) phthalate (DEHP), 2-ethylhexyl diphenyl phosphate (EHDPP) and tributoxyethyl phosphate (TBEP), from printing of packaging materials into food simulants. Two polymer packaging films, i.e. polyethylene film (LDPE, thickness 50 μm) and laminated polyethylene terephthalate and polyethylene film (PET/LDPE 12 μm/35 μm) were printed with flexography technique to obtained the packaging materials with defined content (0.05 mg/dm² and 0.5 mg/dm²) of free above mentioned substances in printing layer. The migration of the tested additives through the packaging films into distilled water and 95% ethanol was studied at 6°C and 23°C. The set-off transfer of all plasticisers into LDPE film in contact with printing was tested at 23°C and 40°C. The results confirmed quite easy migration of all tested additives into 95% ethanol through the LDPE film when more than 90% of the total amount of TBAC and DEHP in printing was extracted into the stimulant during 30 day storage at 23°C at both content levels. Lower migration was found for DEHA (i.e. about 86% and 55% for higher and lower content in printing, respectively), TPEC (about 62% and 50%) and EHDPP (69% for lower content in printing). The migration through the laminated PET/PE film was generally about two thirds of that for LDPE film with an exception of DEHA. For DEHA migration through the both tested films were comparable. As expected the plasticiser transfer into distilled water was about 5-10 times slower compared with the migration into 95% ethanol. Surprisingly high levels of the set off transfer from printing into LDPE film at 40°C after 30 days were determined for all tested plasticisers. The found levels of plasticiser transport were as follows: 32%-40% for TBAC, 28% for DEHP, 25% for DEHA, 12% for TBEP and about 2% for EHDPP. The study confirmed the fact that composition of printing inks can significantly influence the safety of food packaging materials and the necessity of acceptation of suitable legislation for the quality control of printing inks for food packages.

The presence of masked or hidden forms of Fusarium mycotoxins (deoxynivalenol, DON, zearalenone, ZEN and fumonisins B1, B2 and B3) were studied in wheat and maize derived products. Significant amounts of these forms were found both in raw and in processed food commodities. Deoxynivalenol-3-glucoside was found in wheat products up to 30% of DON concentration. Bound forms of fumonisins often account for an equal or even higher amount in comparison with the free forms.

The applicability was evaluated of 16 different oats species and varieties of different provenance in the coeliac diet in view of the composition of the protein complex and immunological testing during two-year experiments (2001 and 2002). Determination was carried out of total nitrogen content (average of evaluated oats collection in 2001 was 2.21%, in 2002 2.78%), protein nitrogen content (average 2001 1.94%, 2002 2.28%), and crude protein (N × 6.25) content (average 2001 13.80%, 2002 17.37%). The proportions of different protein fractions play a decisive role for the aims of this study because, based on the existing knowledge, coeliacally active protein components are present particularly in the prolamin fraction. The percentage of prolamins (determined by discontinual fractionation after Osborne) in the author's evaluated collection of oats species and varieties under the conditions of Central Bohemia reached on average 17.68% of the total protein in 2001, and 15.36% in 2002. The average percentage of albumins and globulins of the total protein reached 36.97% in 2001 and 41.04% in 2002, the average percentage of glutelins of the total proteins was 37.61% in 2001 and 34.10% in 2002, and residual was on average 7.55% in 2001 and 8.70% in 2002, respectively, of the total protein. Electrophoretic analysis of reserve (gluten) proteins (SDS-PAGE ISTA) showed in the oats collection evaluated the percentage of LMW + prolamins in the range 56-77% of the total reserve proteins in 2001, and 52-73% in 2002. The results of A-PAGE electrophoretic analysis of prolamin proteins confirmed the presence of α-prolamins, that ranged in the total content of prolamins from 50 to 88% in 2001, and from 77 to 100% in 2002, while β- + γ-prolamins ranged in 2001 from 11 to 49%, and in 2002 from 0 to 22%. These values do not give serious guarantees for the possible utilisation of oats in the gluten-free diet. The results of the immunological evaluation of the amount of prolamins in oats grains using ELISA showed great differences between different varieties and the experimental years. In 2001, 7 oats samples out of 13 evaluated, and in 2002 10 samples out of 12 evaluated were below the limit for the gluten-free diet (10 mg prolamins (gliadins)/100 g of sample dry matter), but the other varieties exceeded the limit, particularly in 2001, very significantly. The results obtained in the evaluated collection of species and varieties of oats revealed a great variability in the structure of the protein complex and in the immunological testing. In addition a significant effect of the year on the results of all analyses was evident. Based on our results, the use of oats in the diet for coeliac disease can be very risky for these reasons.

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%.

The occurrence of Listeria monocytogenes, Salmonella spp., Bacillus cereus, Staphylococcus spp., Enterococcus spp., and Escherichia coli in raw food materials, food products, and on food contact surfaces after sanitation was investigated during the period of 2005-2006 in three dairy cattle farms (120 samples), one dairy (124 samples), and two meat processing plants (160 samples). A total of 1409 isolates were identified. The epidemiological characterisation and determination of the virulence factors and antimicrobial resistance were performed on selected isolates. The level of bacterial contamination generally decreased during the production process (the contamination of food products was lower than that of raw material). However, the contamination of food contact surfaces was relatively high even after sanitation. Moreover, specific microbiological profiles were found on the inside equipment surfaces in dairy facilities, where genetically closely related multi-resistant strains persisting in biofilm communities may occur as demonstrated for staphylococci. Although the occurrence of potentially significant pathogens was not high, the microorganisms such as L. monocytogenes, Salmonella spp., and shiga-toxin positive E. coli principally contaminated the meat processing plants. B. cereus isolates, among which 76% were positive for diarrhogenic enterotoxin, typically occurred on the inside equipment surfaces and in the heat-treated products.

Fifteen coffee creamers, 10 cream aerosols, and 5 bouillon cubes from the retail market were analysed, principally for their contents of trans-fatty acids that are known to increase the risk of coronary heart disease, and for their contents of 3-chloropropane-1,2-diol (3-MCPD) fatty acid esters that possibly have a bioaccumulation potential. The contents of trans-fatty acids in coffee creamers, cream aerosols and bouillon cubes were in the range of 0.2-32.8%, < LOD - 6.0%, and 0.5-2.1% of total fatty acids, respectively. All samples contained high levels of 3-MCPD fatty acid esters that were determined after releasing the free 3-MCPD by methanolysis. The 3-MCPD levels in coffee creamers, cream aerosols, and bouillon cubes were in the range of 130-730 µg/kg (540-4480 µg/kg fat), 50-730 µg/kg (220-2880 µg/kg fat), and 380-670 µg/kg (2650-4840 µg/kg fat), respectively. The results showed that the refined and hydrogenated oils may represent a certain risk. The highest levels of 3-MCPD esters were found in a sample of refined palm oil (4170 µg/kg). Currently, there is no information available on how these 3-MCPD esters are metabolised, to which extent they are hydrolysed or biosynthesised in the body, to which extent they are deposited in tissues, and how they influence the properties and functions of tissues (if they really do it).

β-Galactosidase is an important industrial enzyme in the hydrolysis of milk and whey lactose. The enzymatic hydrolysis of lactose allows to avoid health and environmental problems posed by this disaccharide. In addition, this enzyme catalyses the formation of galacto-oligosaccharides, which are prebiotic additives for the so-called "healthy foods". β-Galactosidase is one of the relatively few enzymes that have been used in large-scale processes in both free and immobilised forms. This article presents a review of recent trends in immobilisation of β-galactosidase and their application in food industry.

A method to obtain an oligopeptide with high Fischer ratio is described. Corn gluten meal (CGM) was hydrolysed with Alcalase 2.4L using a two-step hydrolysis. In the first-step hydrolysis, the enzyme reaction conditions for hydrolysing CGM were optimised by using the orthogonal experimental design, while pH = 8.0, temperature = 55°C, enzyme to substrate ratio (3:97, w/w), and the substrate concentration = 5% were identified as the optimum conditions, under which up to 11.62% degree of hydrolysis (DH) could be obtained. The hydrolysate was then fractionated by ultrafiltration using a membrane with the molecular cutoff of over 10 kD at 20 kPa. For the second-step hydrolysis, the filtrate was adjusted to pH 6.0, then papain was added at 50°C and the mixture was maintained for 3 hours. The hydrolysate was obtained after inactivating papain and centrifuging. Then the salt (mainly NaCl) in the hydrolysate was removed with an ion exchange resin at the speed of 8 times bed volume per hour, and aromatic amino acids were removed through absorption by active carbon. By using Sephadex G-25 gel filtration chromatography, a peptide mixture with low molecular weights between 1000 and 1300 was obtained. Finally, tests on amino acid composition and free amino acid concentration of oligopeptide solution showed that the oligopeptide had a high Fischer ratio of 34.71 and the yield of 11.59%.

The formation of low molecular carboxylic and hydroxycarboxylic acids as well as sugar and deoxysugar acids from monosaccharides (D-glucose, D-fructose, D-arabinose, DL-glyceraldehyde, and 1,3-dihydroxyacetone) was studied in three different model systems: aqueous and alkaline solutions of potassium peroxodisulfate (K₂S₂O₈), and sodium hydroxide solution. In total, 3 low molecular carboxylic acids (formic, acetic and propionic), 24 hydroxycarboxylic acids, and 12 corresponding lactones were identified and quantified by GC/MS. Formic, acetic, and propionic acids were isolated by extraction with diethyl ether and directly analysed by GC/MS; hydroxycarboxylic acids and their lactones were monitored as their trimethylsilylated derivatives using the same method. Formic, acetic, L-lactic, glycollic, DL-2,4-dihydroxybutanoic acids and aldonic acids derived from the parent sugars were the most abundant compounds in all model systems. Within the models investigated, the yield of carboxylic acids and hydroxycarboxylic acids (together with their lactones) ranged between 9.3-22.2% (n/n) and between 3.6-116.9% (n/n), respectively. The amount of acids was significantly lower in aqueous solutions of K₂S₂O₈ than in the alkaline solutions. The data obtained indicate that lower carboxylic acids are formed by both subsequent reactions (oxidation and/or intramolecular Cannizzaro reaction) of the sugar fragmentation products and direct decomposition of some intermediates such as uloses or hydroperoxides derived from the parent sugars. The acids possessing the original sugar skeleton are formed as a result of sugar oxidation or benzilic acid type rearrangement of deoxyuloses. Lower acids may also be formed by a recombination of free radicals.

Calculations of transient temperatures of food products after they are transferred from a warm environment into a display cabinet, require data on the surface heat transfer coefficient (SHTC). There is no forced air flow in an ordinary display cabinet, so the energy transfer is achieved mainly by free convection, conduction to a supporting plate, and radiation. Theoretical analysis of the heat transfer to a cylindrical sample demonstrates the relative influences of these mechanisms. This work investigates the apparent surface transfer coefficients with metal models. Heated models were placed individually (bare) in containers with and without lids. Each model was surrounded by identical containers filled with water. These were initially at the same temperature as the model or at the mean cabinet temperature. There were one, two, or three layers of these water containers. From the measured time-temperature histories of the model and the air surrounding the model, the SHTCs were calculated as functions of time and transformed into the dependencies between SHTC and temperature difference. The highest SHTCs were observed when the model was placed directly on the metal shelf of the display cabinet. The models surrounded by cool water containers showed lower SHTC values. The lowest SHTC values were found with the models placed in the middle of three layers of warm water containers. Placing the model on an insulating base leads to a lower SHTC. This effect confirms that the heat conduction through the substrate increases the heat transfer from the model and thus increases the average value of the apparent SHTC.

The compositions and concentrations of lipid classes, fatty acids, tocopherols were determined in the lipids from blue-green microalga Spirulina platensis. Total lipids (TL) recovered using chloroform: methanol (2:1, v/v) were found to be 163.5 g/kg (on dry weight basis). The level of neutral lipids was the highest, followed by glycolipids and phospholipids, respectively. Among TL and lipid classes, palmitic, γ-linolenic and linoleic acids were the dominating fatty acids. Compared to the neutral lipids, the polar fractions were generally characterised by higher percentages of saturated fatty acids. The recovered lipids were characterised by high percentage of tocopherols, wherein γ-tocopherol constitutes about 73% of total tocopherols present, the rest being γ-tocopherol. Spirulina platensis lipids exhibited a strong radical scavenging activity towards stable DPPH free radicals, whereas 27% of DPPH radicals were quenched after 2 h incubation. TL and lipid classes inhibited the growth of different microorganisms except gram-negative bacteria. At high concentrations, the tested lipids appeared more effective against A. niger (28.3 ± 1.53 mm). The information obtained in the present investigation is useful for lipid characterisation and further chemical and nutritional investigations of Spirulina platensis.

Coenzyme Q₁₀ is an important mitochondrial redox component and endogenously produced lipid-soluble antioxidant of the human organism. It plays a crucial role in the generation of cellular energy, enhances the immune system, and acts as a free radical scavenger. Ageing, poor eating habits, stress, and infection - they all affect the organism's ability to provide adequate amounts of CoQ₁₀. After the age of about 35, the organism begins to lose the ability to synthesise CoQ₁₀ from food and its deficiency develops. Many researches suggest that using CoQ₁₀ supplements alone or in combination with other nutritional supplements may help maintain health of elderly people or treat some of the health problems or diseases. Due to these functions, CoQ₁₀ finds its application in different commercial branches such as food, cosmetic, or pharmaceutical industries. This review article gives a survey of the history, chemical and physical properties, biochemistry and antioxidant activity of CoQ₁₀ in the human organism. It discusses levels of CoQ₁₀ in the organisms of healthy people, stressed people, and patients with various diseases. This paper shows the distribution and contents of two ubiquinones in foods, especially in several kinds of grapes, the benefits of CoQ₁₀ as nutritional and topical supplements and its therapeutic applications in various diseases.

Handling with genetically modified organisms (GMOs) is regulated namely in EC. Laboratories often use polymerase chain reaction (PCR) based screening methods to monitor the presence of GM particles in food commodities as a cost effective approach. The reliability was tested of such screening using 35S CaMV promoter as the target sequences. Soya grown from non-GM cultivar as declared by a seed company was investigated after the harvest, transport to the silo, and before processing. The results based on PCR and real-time PCR analysis clearly showed that, the contamination with debris of other species, dust during transport, storage, and other kind of handling led to contamination with detectable amounts of Cauliflower mosaic virus (CaMV). Impurities are allowed by EC regulations but may, as we have shown, interfere with the analytical procedures based on PCR. The identification of 35S CaMV promoter and NOS terminator in food with uncertain history and no approved specific events may indicate unknown GMOs and perhaps emergency situation.

The effects of inulin HPX and maltodextrins, and also the potentially probiotic Lactobacillus plantarum 14 strain, used separately and in combination in white cheese production, on the gastrointestinal microflora of Wistar rats was investigated. The prebiotic addition to the cheese was 2.5%, whereas probiotic and synbiotic cheeses contained at least 10⁷ CFU/g of live L. plantarum cells. The counts of Bifidobacterium sp., Lactobacillus, coliforms, and the most probable number of anaerobic proteolytic bacteria were evaluated. After a 10-day feeding experiment, significant changes (P < 0.05) were noted in the most probable number of anaerobic proteolytic bacteria spores, which was the highest in the group receiving a diet with the cheese containing the potentially probiotic strain and inulin HPX. A short-time ingestion of low doses of prebiotics or synbiotics did not alter the counts of Lactobacillus, Bifidobacterium, and coliforms in healthy rats.

The aim of the present work is to evaluate the impacts of four different sterilising modes (110°C 100 min, 115°C 32 min, 120°C 10 min, and 125°C 3.2 min - with a constant lethal effect on microorganisms) on some chemical (pH, total and bio-available lysine, and ammonia content), microbiological, and sensory (shade and acceptability) properties of processed cheese depending on the lactose additions (0.0-2.0% w/w). All sterilising modes used were sufficient to inactivate the microorganism groups observed (total number of microorganisms, colony forming units of yeasts and/or moulds, number of spore-forming microorganisms). The falling sterilisation temperature kept for an adequately prolonged period of time caused darkening of the processed cheese and a decline of their acceptability. Consequently, greater losses of lysine and ammonia content increase occurred when the sterilisation temperature decreased. Compared to non-sterilised products, the smallest changes were detected in the cheese treated with temperatures 125°C for 3.2 min, and 120°C for 10 minutes. The decrease of the processed cheese quality was more apparent with the growing lactose concentration.

The purpose of this study was to investigate the relationship between the carcass weight and the level of skatole in boar back fat samples with descriptive sensory profiles (trained sensory panel) immediately after heating the fat samples (warm). A weak correlation was found between the carcass weight and skatole level in fat (P > 0.05). Between skatole levels in the fat of boars, whose carcass weight was below 70 kg, and of those with the carcass weight equal or above 70 kg, there was a statistically significant difference (P < 0.05). The average content of skatole in the fat tissue of the boars < 70 kg, (0.18 ± 0.09 mg/kg fat, respectively) was below the commonly used respective thresholds for tainted meat (0.20 mg/kg fat), 53% of the samples showed the values of ≤ 20 mg/kg, and 73% of the samples the values of ≤ 25 mg/kg. In the group ≥ 70 kg (0.40 ± 0.39 mg/kg fat, respectively), 80% of the samples revealed the values of ≥ 20 mg/kg, and 66% of the samples the values of ≥ 25 mg/kg. Our results show that a positive, compelling and statistically highly significant correlation exists between the skatole level and the sensory assessment of skatole intensity in fat.

The determination of polyphenols by spectrophotometric detection is complicated due to their low concentrations in beer. The beer samples have to be pre-concentrated before using the spectrophotometric detection for their quantification. An analytical method based on solid-phase extraction (SPE) and followed by high performance liquid chromatographic separation with diode-array detection is used for the determination of free gallic, protocatechuic, caffeic, p-coumaric, ferulic and salicylic acids, of (+)-catechin, (-)-epicatechin, and quercetin. These phenolic compounds participate in colloidal and sensory stability of beer. Six different SPE cartridges were tested and three different types of elution with the most appropriate solvents (acetonitrile, acetone and methanol) were used. The performance of the HPLC method was assessed by the evaluation of parameters such as absolute recovery, relative standard deviation (RSD - lower than 10%), the limit of quantification (LOQ), and the limit of detection (LOD). The polyphenol content in various types of Czech beer is presented.

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.

Phytic acid has been considered to be an antinutrient due to its ability to bind minerals and proteins, either directly or indirectly, thus changing their solubility, functionality, absorption, and digestibility. In this study, the influence of the flour type (type 500, type 850, and whole meal flour) and three different breadmaking procedures (direct, indirect, and with sourdough addition) on phytic acid was investigated. The results showed that the flour type influenced the phytic acid content. The phytic acid contents of flour type 500, type 850, and whole meal flour was 0.4380, 0.5756, and 0.9460 g/100 g dm, respectively. The dough and bread prepared from flour with a higher phytic acid content also contained higher amount of phytic acid. During fermentation and baking, degradation of phytic acid occurred. Phytic acid was also influenced by pH. Samples of lower pH had a lower phytic acid content. Dough prepared from flour type 500 and type 850 with 10% addition of sourdough had especially low phytic acid contents, and the bread prepared from the respective dough contained no phytic acid at all.

The fractionation of Cd, Cu, Mo, Ni, and Zn species in extracts of rye (cv. Fernando) seedlings (grown up in both standard and Cd²⁺-enriched medium) and rye flour was performed by SEC/ICP-MS method. The majority of Cu, Zn, and Ni in all samples were bound in the 1-2 kDa fraction. Molybdenum occurred in all samples in the fraction of 3 kDa. During five days of cultivation in a solution of 30 µmol/l Cd²⁺, the plants accumulated as much as 5 mg/kg fresh matter of Cd, but its soluble portion represented only 12-15%. The prevailing portion of Cd complexes was contained in the fraction of 3 kDa, while the minor part occurred in the fraction of 20 kDa. The speciation of elevated Cd in plants differs from that of other metals present at a physiological level. The metal-rich fractions of the extracts of all samples (i.e. those of 1-2 kDa) were refined by immobilised metal affinity chromatography. The isolated ligands of trace elements were peptides rich in dicarboxylic aminoacids.

The quality of water has to be controlled and monitored by drinking water suppliers during all stages of the treatment process from the water sources to the end of distribution systems. The research, performed in Czech Republic from 2006 to 2008, deals with the assessment of the affect of water tanks on the quality of water supplied to consumers, specifically from various points of view: microbiological, biological and physic-chemical changes in water accumulation. Also studied was the influence of the air on the quality of accumulated water (secondary contamination), the influence of the structural layout and hydraulic ratios. In the project quick screening methods (paddle testers and BART^TM tests) were applied in the collection of water samples and scrapings from wetted surfaces of water tanks. The results of the contamination degree discovered in the course of the project solution will serve as basic data for a scale that should evaluate the degree of water tank pollution as well as for resulting corrective measures or optimisation of water tank cleaning. The recommendations of limits for a scraping sample are based especially on the microbiological parameters. Secondary air contamination plays an important role in maintains of biologically stable water. Based on the number of microbial contamination discovered water tanks will be categorised and methods of suitable measures to be taken will be stipulated, operation optimisation as well as cleaning (schedule, methods and frequency of cleaning). The water quality in a storage tanks depends on their maintenance, e.g., to prevent the plaster falling on water surface, the use of antifungal surface coatings (prevention the growth of fungi on walls), the use of ceramics surface of reservoir walls, dark conditions (no windows or blue sheets) in all technological units, the prevention of dust fall out, the selection of suitable air condition and special air filters.

The absence of good agricultural and manufacturing practices in the production and postharvest handling of fresh produce, such as green asparagus or green onions increase the contamination risk by biological hazards like Salmonella. The objective of this work was to investigate the efficacy of chlorine (200 and 250 ppm), hydrogen peroxide (1.5% and 2%), and lactic acid (1.5% and 2%) sanitisers during different exposure times (40, 60, and 90 s) on the reduction of Salmonella enterica subspecie enterica serovar Typhimurium in inoculated fresh green asparagus and green onions. Washing with clean water only reduced < 1 log10 CFU/g in both vegetables. The most effective sanitiser evaluated for fresh green asparagus and green onions disinfection appeared to be 2% lactic acid reducing Salmonella growth close to 3 log₁₀ CFU/g. Hydrogen peroxide was the least effective agent for Salmonella Typhimurium reduction. No effect was observed of the exposure time of inoculated product to sanitiser up to 90 seconds. These results confirm that lactic acid could be used as an alternative for fresh green asparagus and green onions sanitation.

Proteolysis is the principal and most complex biochemical event occurring during the maturation of the majority of ripened cheese varieties. In addition to softening the cheese body, proteolysis influences the development of cheese flavour via the formation of amino acid and peptides which make a direct contribution to flavour. Goat, cow and sheep cheeses have been elaborated with raw milk and calf rennet. The extent of proteolysis was monitored over six months of ripening and means of HPLC peptide profile analysis. The influence of season on the changes in hydrophobic and hydrophilic peptides and the HO/HI ratio during the ripening of the cheeses were studied.

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.

Oxidation changes of different types of vegetable oils were studied during microwave heating. Samples of vegetable oils (rapeseed, sunflower, soybean and corn oil), commercially available at the market in the Czech Republic, were heated in a microwave oven. Parameters as peroxide value, conjugated dienes and trienes levels were determined in oil samples before and after heating in the period from 3 to 30 minutes.