Bohuslava Tremlová

Chemical, instrumental and sensory characteristics of cooked pork ham

Instrumental, chemical and sensory parameters of cooked pork ham were evaluated. Principal component analysis was carried out on the basis of the instrumental variables related to colour and texture. The four PCs account for almost 94% of the total variance in the data set. The PCA only separated 3 hams with a(∗)>10. Hardness was correlated with non-collagen muscle protein (P⩽0.01), gumminess (P⩽0.01) and ash (P⩽0.05). Sensory evaluated tenderness showed positive significant correlation with L(∗) (P⩽0.01). The most important colour parameter seems to be a(∗), which was negatively correlated with sensory evaluated parameter colour (P⩽0.01). The PCA performed on all parameters (sensory, chemical and textural) discriminated two groups of hams differing in non-collagen muscle protein content and hardness.

Detection of allergenic parvalbumin of Atlantic and Pacific herrings in fish products by PCR

The conventional polymerase chain reaction (PCR) method to detect the major allergenic protein parvalbumin beta 2 of Atlantic herring (Clupea harengus) and Pacific herring (Clupea pallasii) was developed. The specific set of primers for the amplification of the partial genomic sequence of the pvalb 2 gene encoding the main fish allergen of both herrings was designed and applied to the investigation of 24 commercial fish products. The targeted amplicon size was 189 bp of pvalb 2 gene of Atlantic herring and Pacific herring. As the internal amplification control, the DNA of 18S rRNA gene for eukaryotes (141 bp) was successfully used. The specificity of designed primer pair using 26 various fish species was assessed. The intrinsic detection limit was 10 pg µl−1 of the present specific DNA. Atlantic herring or Pacific herring allergenic parvalbumins were detected in 22 investigated fish products in conformity with the package declaration. Two fish products were negative in spite of the declaration. The proposed PCR method is specific enough and can be used for the detection of Atlantic and Pacific herrings’ major allergen parvalbumin beta 2 in fish food products.

Application of principal component analysis method for characterization chemical, technological, and textural parameters of farmed and pastured red deer

ABSTRACT Sixteen male red deer (age <1.5 year), both farm reared and pastured in Slovakia, were assessed with an emphasis on the variability of pH, chemical, structural, and textural parameters of their Musculus longissimus thoracis et. lumborum. Pastured deer had a higher pH than farmed deer. Regarding chemical compounds, meat from pastured deer contained less protein, fat, and ash, and regarding technological parameters, drip loss and cooking loss was higher when fried at 80°C. Meat cohesiveness was quite similar for both groups, while shear force was lower in pastured deer after being roasted in an oven and being fried, and it had less coefficients of variation than hardness. The total variation higher than 85% was explained by the first five principal components for pH, chemical, and technological parameters, and 86% for textural parameters. The principal component analysis illustratively divided the pastured and farmed deer according to the assessed parameters.

Anthocyanins in purple and blue wheat grains and in resulting bread: quantity, composition, and thermal stability

Abstract The anthocyanin composition of blue (Triticum aestivum L., cv. Skorpion) and purple wheat (Triticum aethiopicum JAKUBZ cv. Abyssinskaja arrasajta cv. Abyssinskaja arrasajta), cultivated in the Czech Republic, and of the prepared whole blue and purple wheat bread was determined. In blue and purple wheat, 19 and 26 anthocyanins, respectively, were tentatively identified by liquid chromatography and mass spectrometry. The total content of anthocyanins determined in blue and purple wheat was 9.26 and 13.23 mgkg−1, respectively. The breads were baked at 240 and 180 °C. Some significant differences in anthocyanins content were observed between breads prepared at different baking temperatures. The content of cyanidin-3-glucoside, delphinidin-3-glucoside and pelargonidin-3-glucoside was determinated in starting material, whole meal flours and baked breads. These kinds of wheat are suitable for baking bread, since intake of anthocyanins may play an important role in the prevention of human diseases.

Comparison of immunohistochemical, histochemical and immunochemical methods for the detection of wheat protein allergens in meat samples and cooked, dry, raw and fermented sausage samples

Nowadays is it a common practice to add vegetable protein in the production of meat products. Because of the possible substitution of high-quality raw meat with vegetable protein without the labelling the product package and because of the allergenic potential of many vegetable proteins, it is important to develop accurate methods for its detection. The objective of the study was to compare histochemical, immunochemical (ELISA, ALERT gliadin screening test) and immunohistochemical methods for the detection of wheat protein in meat samples and sausages. Histochemical methods were useful for the detection of flour in meat samples, but the immunohistochemical method was better for the detection of wheat protein. ALERT gliadin screening test detected gliadin from 10 mg kg−1, while an immunohistochemical method detected wheat protein concentrations from 1 g kg−1 and an ELISA method detected wheat protein concentrations from 4 g kg−1. ALERT gliadin screening test showed results within 1 day, whilst an ELISA detection method took 2 days, and an immunohistochemical procedure took 5 days at the soonest, all including sample preparation. This study also focused on optimisation of an immunohistochemical method for samples of cooked sausage. In addition, three samples were sufficient for wheat protein detection at a concentration of 1 g kg−1 (and greater) with a confidence level greater than 95%.

Microscopic determination of bamboo fiber in meat products

Fiber, a suitable additive to meat products with water-holding capacity, reduces curing losses and maintains juiciness of the meat. The risk is the use of excessive amounts of flour or other ingredients of vegetable origin, in which the fiber is contained. In some cases, sensory characteristics of products can be affected. Detection of fiber may be prevention of adulteration in some meat products. It is therefore very important to regularly detect the amount of fiber in meat products and check its contents. Fiber in meat products can be detected by various methods, applied are for example gravimetric, spectroscopic, histochemical, and microscopic methods. For this reason, a model meat product (Vysocina salami) was prepared in our experiment with the addition of bamboo fiber of selected concentrations of 0%, 2%, and 3%. Subsequently, a series of microscopic sections was made on different days of curing (day no. 7, 14 of the drying phase and 28, 42 of storage). Individual sections were examined and captured using a polarization microscope, the amounts of fiber in individual sections were analyzed by means of image analysis software and the values obtained were compared with each other. Also the influence of drying on the measured area of fiber in sections was monitored. The results indicate a noticeable reduction in the area of fiber until the seventh day of ripening, which is caused by the rapid loss of water in the product. In contrast, sections of products from the following days of drying contained mildly increased concentrations of fiber, which was caused by gradual drying of the products, while the area of fiber refrained form becoming smaller. Between the individual days of drying, a difference that was statistically significant was demonstrated from the 14th day of (storage or drying). Correlation was observed between the date of (storage or drying) and amount of added fiber. Among the tested mean values for the sample with the addition of fiber concentration of 2 % an insignificant difference was found. The difference between test values (day/fiber) in the sample with addition of 3% fiber was, however, statistically significant.

Determination of Ketchup Sensory Texture Acceptability and Examination of Determining Factors as a Basis for Product Optimization

The aim of this study was to examine possible usage of instrumental determination of selected texture parameters to estimate sensory texture acceptability of ketchups. Likewise, the authors focused on examination whether the consumer’s perception of texture acceptability is connected to the selected factors related to the ingredients and production technology. Yet another aim was to describe the selected textural parameters of ketchups available in the European market. Within the frame of this study, 29 samples of ketchups were analyzed by means of instrumental and sensory texture analysis. Further, a survey research was carried out with the results showing that the texture was the second most significant parameter for the consumer’s choice of a particular product. The average evaluation of sensory texture acceptability reached the values from 3.78 to 7.67. Analysis of the evaluation results of textural parameters based on the values of Pearson’s correlation coefficient confirmed a high correlation (p < 0.05) between instrumental and sensory determined viscosity and density. However, none of these partial textural parameters affected the sensory acceptability of the texture separately. Thus, using the instrumental analysis for estimation of the sensory texture acceptability of ketchups is not possible. For the optimization and control of ketchup texture in practice, sensory analysis is essential.

Evaluation of significant pigments in green teas of different origin.

This work monitors flavonoid pigments (theaflavins and thearubigins), and chlorophyll in green teas from different growing regions (India, China, Russia, Vietnam). These pigments affect the quality of the finished tea infusion and their quantity is affected by the way of tea processing (fermentation). 15 samples of green loose teas were selected for the analysis. The content of these pigments was determined using UV-Vis spectrophotometry, the concentration of flavonoid pigments was measured at a wavelength of 665 nm (theaflavins) and 825 nm (thearubigins). Concentration of flavonoid pigments was determined using the standard conversion coefficients, which are 38.7 for TRs and 1.4 for TFs. Chlorophyll concentration was measured at 642.5 and 660 nm. Chlorophyll concentration was determined by the conversion using international standard conversion coefficients and calculation of linear regressions. The results were statistically processed and evaluated in the program of UNISTAT version 5.6. The total amount of chlorophyll ranged from 0.20 to 1.33 mg/L of tea. Concentrations of theaflavin ranged from 0.15 to 0.66 g/100 g of tea and TRs from 2.00 to 11.15 g/100 g of tea. The results showed that the amount of theaflavins, thearubigins and chlorophyll in green teas varied (P <0,05), especially in teas from lowlands in Vietnam and Krasnodar (Russia). Statistically demonstrable difference (P <0,05) in the content of pigments was also recorded in a group of Indian teas (from lowlands) and, from a group of Chinese teas, a statistical difference (P <0,05) was demonstrated in the content of pigments in the mountain teas. On the basis of the results it can be concluded that the quality of green tea is mainly influenced by the processing method depending on the processing area (the factory), than by their country of origin.

Immunofluorescent determination of wheat protein in meat products

In food industry nowadays, there are various plant-origin protein additives which are meant for production of meat products. Among the most frequent additives of this type there are different kinds of flour, starch, fiber, and plant-origin proteins. Their usage at present is limited by the existing legislation not to prevent consumer deception but also for reasons of possible influence on consumer health. Therefore, this problem is paid a lot of attention not only in the Czech Republic but also all over the world. The main risk is seen in the impossibility to choose a suitable foodstuff for an individual prone to allergic reactions. Potential allergens are also often plant-origin raw materials which are added into foodstuffs for their technological qualities and low price. Wheat is widely cultivated cereal as well as an important source of proteins. After ingestion or inhalation, wheat proteins may cause adverse reactions. These adverse effects include a wide range of disorders which are dependent on the method of contact with wheat protein. These adverse effects can then take the form of various clinical manifestations, such as celiac disease, T-cell mediated inflammatory bowel disease, dermatitis, skin rash, breathing difficulties, allergy to pollen or to wheat flour or food allergy to foodstuffs containing gluten. The only possible protection against adverse immune reactions for those with food allergies is strictly excluding the allergen from their diet. Although the number of studies dealing with the reduction or loss of allergenicity is increasing, yet these practices are not common. Most of the population suffering from food allergies is thus still dependent on strict exclusion of foodstuffs causing adverse allergic reactions from their diet. In order to avoid misleading consumers and also to protect allergic consumers, analytical methods applicable to all types of foodstuffs have been developed. Unfortunately, detection of allergens in foodstuffs is relatively difficult because of the fact that they occur in trace amounts and are often masked by various parts of the product. This paper deals with detection of wheat protein in meat products bought in the retail network of the Czech Republic. Ten cooked meat products, especially types of sausages and soft salami which stated wheat protein in their composition, were examined. The samples were processed using the method of immunofluorescence and stained with Texas Red fluorochrome. The presence of wheat protein was demonstrated in all the examined meat products. From the results it follows that the method of immunofluorescence is suitable for detection of wheat protein in meat products. Normal 0 21 false false false CS JA X-NONE

Pork protein addition effect on structural and qualitative parameters of frankfurter-type sausage: Pork protein effect on frankfurter-type sausage

BACKGROUND Several raw materials and additives are used in meat production. In terms of origin, proteins which are the closest related to meat are derived from slaughtered carcasses. The aim of the work was to assess the effect of their addition on the microstructure, texture and colour of frankfurter-type meat products. RESULTS Calleja staining, instrumental textural analysis and colour analysis were applied. The microscopic results were evaluated qualitatively. Canonical component and Tukeys HSD were used for textural and RGB evaluation. Microscopically, protein matrix formation in products containing pork haemoglobin (155_16) and pork plasma P (158_16) was found to be different from that in other samples. Texture analysis revealed differences (P < 0.05) in shear force between pork haemoglobin 155_16 and all tested samples, in the hardness between the control (154_16) and pork collagen protein (157_16) and between 157_16 and 160_16. Chewiness showed differences between control 154_16 and collagen proteins 157_16. Colour analysis showed a difference between pork haemoglobin (155_16) and other products (P < 0.05) by component analysis. CONCLUSION All tested additives were incorporated into the protein matrix. Therefore, they may be used as additives even for unrecommended meat products. Addition of pork haemoglobin has a significant impact on the colour of the final product.