Ľubomír Belej

Identification of differences in chemical composition among whole stick and sliced Nitran salamis trough principal component analysis

The subject of this work was to examine differences in chemical composition of sliced and whole stick Nitran salamis, purchased from various manufacturers. Nitran salamis are traditional dry fermented meat products of Slovak origin. Taking into account variations in raw materials, production process and potential adulteration, differences in chemical composition within one brand of salami from different manufacturers might be expected. Ten salamis were determined for basic chemical composition attributes and Principal Component Analysis was applied on data matrix to identify anomalous ones. It has been shown that six attributes, namely: protein without collagen of total protein, total protein, total meat, total fat, collagen of total protein and NaCl, were the most important for salamis as first two Principal Components together explained 70.16% of variance among them. Nitran D was found to be the most anomalous salami, as had the lowest value of protein without collagen of total protein (14.14% ±0.26%), total protein (17.42% ±0.44%), total meat (120.29% ±0.98%) and the highest one of total fat (50.85% ±0.95%), collagen of total protein (18.83% ±0.50%) and NaCl (9.55% ±1.93%), when compared to its whole stick variant Nitran C and other samples. In addition to collagen of total protein content, Nitran D together with Nitran A, F and H did not satisfied the legislatively determined criterion, which is ≤16%. This suggested that extra connective tissues were added to intermediate products, which resulted in high variability and inferior quality of final products. It is a common practice in the meat industry to increase the protein content or water binding properties of meat products.

Phytoestrogens dietary intake and health status of retiree from middle-notrh Slovakia region

Phytoestrogens found in foods of plant origin presents chemical substances that possess a wide range of biochemical benefits. It has been found that they contribute in different health related problems. A wide range of commonly consumed foods contain appreciable amounts of phytoestrogens. Consumption of diet rich to phytoestrogen acts as a protective factor against many diseases such as cardiovascular diseases, post-menopausal symptoms in the context of osteoporosis, cancerous illnesses of colon, prostate and breast. Three main classes of phytoestrogens covers: isoflavones, lignans and coumestans. Selected nine major phytoestrogens had been analyzed simultaneously in the same foods. Questionnaire designed to determine intake frequency as well as amount of selected foods and the most common diseases presented in the population has been used to find relationships between dietary habits and health status. Evaluation of selected goals in the present study has been realized in cooperation with 140 respondents in retired age (divided into Males - covered by 34 individuals and Females - 106 individuals), comming from middle-north Slovakia region. On the base of collected data it can be concluded, that evaluated population is presented by high values of lignans intake and particularly secoisolariciresinol, mainly caused by relative high proportion of cereals and linseed in the diet. Furthermore, the relationship between phytoestrogens intake and eating habits as well as its contribution in protection against selected diseases was demonstrated. Normal 0 21 false false false CS JA X-NONE

Comparison of the sensitivity of determining soyeabean allergens by ELISA method and SYBR green I

Normal 0 false false false SK JA X-NONE The aim of this study was to compare the suitability of two methods for detecting defatted soybean powder; SYBR Green I Real-time PCR and enzyme-linked immunosorbent assay (ELISA). Analysis of 20 artificially contaminated samples prepared by simple dilution with wheat flour revealed that both techniques were able to detect defatted soybean powder, although there were significant differences between the two methods. Wheat flour contamination with defatted soybean powder was detected in samples 1-5, (0.012 %; 120 mg.kg -1 ), but not in samples with lower contamination with soybean powder saples 6-20 using SYBR Green I real-time PCR. Samples 1-10 could not be quantified by ELISA as the absorbance values were greater than the detection limit, and while samples 11-20 were measured, only the values of samples 16, 17 and 18 were within the guaranteed quantification range specified by the ELISA kit manufacturer. Defatted soybean powder contamination was detected in samples 19 and 20, but absorbance values were highly similar to those of the negative control sample.

The effect of UV-C irradiation on grape juice turbidity, sensoric properties and microbial count

In this work, we investigated the effect of UV-C radiation (254 nm) on turbidity, microbial count and sensoric properties of the grape juices treated or not treated with sulphur dioxide. The UV-C radiation is considered to be germicidal against microorganisms. This technology is routinely used to treat drinking water. Application of this method for the purpose of treating the wine was tested in few studies. These studies have shown a positive effect on the inactivation of microorganisms, but they not dealt in detail with the sensory properties of grape juice after the treatment. The main idea of using this method appears to eliminate the sulphur dioxide from wine making technology. There are people who have a genuine allergy to sulfites, and these allergies are often linked with asthma. These people have an rapid onset of symptoms when drinking liquids like wine treated with sulphur dioxide. In our work we have found that the application of this method of treating the grape juice is problematic. Intensity of UV-C radiation increases the turbidity of grape juices. This effect was observed in all grape juices with or without addition of sulphur dioxide and also in clarified or not clarified grape juices. We found that UV-C radiation negatively affect the sensory properties of grape juices. This effect was more pronounced in grape juices treated with SO2. The smell and taste were significantly negatively changed. Exposure of grape juice treated with sulphur dioxide to UV-C radiation can probably lead to arising the sulphur compounds, which affects the smell and taste of grape juices. Also, it is very likely that the negative change in taste and smell may affect the quality of produced wines. For this purpose, we do not recommend to use UV-C treatment for the grape juice treatment. It will be interesting to conduct a detailed analysis of the grape juices composition before and after UV-C radiation treatment.

Authentication of caprine milk and cheese by commercial qPCR assay

The objective of the study was to investigate potential adulteration of commercial caprine milks and cheeses with bovine milk using commercial qPCR assay. The assay comprised of bovine-, ovine- and caprine-specific primers and TaqMan probe and mammalian internal control. Specificity, sensitivity, linearity, reproducibility and efficiency of the bovine assay were tested as well. Specificity was verified by running reaction on the DNA of other milk-producing species (caprine and ovine) and made-up bovine-caprine (v/v) milk mixes. In both experiments, a bovine DNA fragment was amplified whereas no amplification was obtained from the other species. Sensitivity, linearity, reproducibility and efficiency were tested on 10-fold dilution series of 10 ng bovine DNA. The assay has shown good linearity (R 2 = 0.983) within whole range, with efficiency of 86% and excellent reproducibility (SD around the C T for the technical replicates <0.5). The sensitivity was adequate, as calculated LOD and LOQ were 1.44 pg and 2.94 pg of bovine DNA, respectively. Finally, the assay was used to authenticate 5 caprine milk samples and 5 caprine cheese samples, purchased from local supermarkets. Totally, 1 milk sample has shown the fluorescence signal, which exceeded baseline in cycle 39.01 ±0.69. However, the signal was above LOD and LOQ suggesting that there could not be unambiguously declared any adulteration with bovine milk. Amplification of bovine-specific DNA was not observed in the other samples indicating products were not adulterated. The commercial qPCR assay has proved that real-time PCR assays, as well as DNA-based techniques in a general, are the excellent and reliable tools for fighting with frauds in the food industry and protecting the public health. Normal 0 21 false false false SK X-NONE X-NONE

Detection of ovine milk adulteration using taqman real-time pcr assay

Food safety, quality and composition have become the subjects of increasing public concern. To prevent fraud and enhance quality assurance, credible analysis of dairy products is crucial. Bovine milk is more widely available and cheaper than milk of sheep and goat. Bovine milk is also processed in large quantities to produce a range of dairy produce. DNA-based methods have proven to be more reliable, because of the stability of DNA under the conditions of high temperature, high pressure, and chemical treatment used during the processing of some food products. The commercial InnuDETECT cheese assay based on the principle TaqMan real-time PCR systems have been tested for the identification and quantification of bovine DNA in ovine milk samples. DNA was extracted using the InnuPREP DNA Mini Kit and quantified by the QuantiFluor dsDNA system. The assay showed good linearity, with correlation coefficient of R2 = 0.983 and efficiency of 86%. The internal control amplified fragment from different mammalian species (cow, sheep and goat), with similar CT values. Detection of bovine DNA in milk mixtures was achieved even in samples containing 0.5% of bovine milk. The InnuDETECT cheese assay has been successfully used to measure bovine DNA in ovine milk, and will prove useful for bovine species identification and quantitative authentication of animal-derived products.

DETERMINATION OF SELECTED SPECIES TEXTURE PROCESSED CHEESE AND PROCESSED PRODUCTS DIFFERENT BATCHES UNDER DIFFERENT CONDITIONS KEEP THEM FOR EATING QUALITY

In this work we evaluated the texture of processed cheese and processed products. The products we have retained as it is assumed that they kept and used by ordinary consumers. This means that the product purchased certain period has elapsed, we included in our test conditions. Texture analysis help provide the basic methods and explaining procedures for analysis, also provide for the initiation of new types of tests or review new products and therefore be dealt with differences in the products according to specific requirements. Sensory panels also play an important role in the evaluation of food products, but the use of texture analyzer eliminates human error and tests carried out are consistent and accurate. Analysis of texture help manufacturers monitor and analyze the texture characteristics of their products. From the producers can modify the product key factors such as characteristics of the milk into cheese and can also modify manufacturing processes to the functional properties of cheese. Fulfilling the basic requirements to maintain their properties and cheese functionality.

Determination of the species specificity of the primers for the detection of chicken and turkey meat by realtime PCR method

The aim of this work was to use TaqMan Real-Time PCR for quantitative authentication of chicken and turkey meat. To meet this purpose, a specific pair of primers and TaqMan probe was used. The test was aimed at identifying the reaction cycle of turkey and chicken meat using by two sets of primers. With first set of primer designed for chicken we obtained the following results: Cp = 16.18 for 100% chicken DNA Cp = 29, 18 100% turkey DNA It was also amplified DNA of pig that exceeded the detection threshold fluorescence intensities in the 31.07 cycle (Cp = 31.07). Using primers designed for turkey we obtained the following results Cp = 31.16 for 100% CHDNA, Cp =16.18 100% TDNA. It was also amplified the 100% DNA of rabbit in 31.63 cycle (Cp = 31.63) and deer in cycle 32 (Cp = 32). The DNA of all other animal species was amplificated after more than 35 cycles (Cp >35). It follows that the second detection primer pair is specific enough to unrelated species of animals by 30 cycles of the reaction. Species authentication based on DNA analysis from this perspective overcomes all the shortcomings of proteins. At present, DNA analysis use different types of PCR. Is the most progressive Real-time PCR, which is suitable for the specific use of detection (primers and TaqMan probe). The TaqMan Real-time PCR is within the sensitivity and specificity, clearly one of the best methods for identifying the species of chicken and turkey meat. The specificity of this method, however, depends primarily on the specificity of the primers and TaqMan probe. The 30 cycle reaction was chosen by us as the threshold for specificity using primers for authentication chicken and turkey meat.

THE YIELD OF DNA IN THERMAL TERATED DEER MEAT

Residuals of DNA are one of the most important factors for detection, traceability and reverse authentication of deer meat. In this project we isolated DNA from deer processed meat and analysed by electrophoresis. Goal of the study was compute ratio between raw meat and several heat processed deer meat. Samples were prepared by five heat treatment techniques (pan roasted with temperature 180-240°C, fried with 156°C, braised with temperature 100-150°C, boiled in 100.2°C water and autoclaved in different time intervals). The highest amount of residual DNA 1927ng was obtained with two hours boiled sample. The lowest value 89.89ng was obtained with one hour braised sample. In technological adjustments highest amount of DNA and 1927ng, so the total yield of 192.7ng.- l was observed in the sample we cooked for two hours at boiling temperature. doi:10.5219/153

OPTIMALISATION OF SPECIES IDENTIFICATION OF COMMON CARP (CYPRINUS CARPIO) USING SYBR ® GREEN I REAL-TIME PCR METHOD

European Union Member States, together with a number of countries around the world, places great emphasis on ensuring the protection of consumers as a potential food allergic from food allergies. to inform consumers that their product may contain any of the risk of allergenic ingredients. For species identification of fish and fish products as a potential food allergens are used by many analytical methods as well as their authentication. We are in our work applied the method of SYBR ® Green I. Real-Time PCR. We focused on pre-designed molecular - genetic marker of common carp (Cyprinus carpio), which comes from the mtDNA control D - loop area. We analyzed its presence in DNA isolates from the 5 kinds of freshwater fish, diluted to 10 % concentration. Results of using the optimized SYBR ® Green I Real-Time PCR method for species identification common carp (Cyprinus carpio) indicate to its suitability.