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Carrageenan is a seaweed polysaccharide widely used as a food gelling and thickening agent. The New Methylene Blue dye was tested as an analytical reagent for the quantification of carrageenan in commercial jelly samples. The main spectral peaks of the dye decrease with increasing carrageenan-to-dye molar ratio up to 1. Three analytical procedures were tested: (i) spectrophotometric measurement at 590 nm, (ii) smartphone-based color measurement within the RGB color model and (iii) spectrophotometric titration at 625 nm. All the procedures provide straight calibration lines. Spectrophotometry provides better linearity as compared to smartphone-based colorimetry. Range of determination is dependent on type and purity of carrageenan. The spectrophotometric titration procedure provides lower values of limit of determination due to longer optical path used. Typical food additives used in jelly deserts do not interfere significantly with the proposed analytical approach.

To increase production efficiency of meat products, milk protein additives are often used. Despite a number of advantages, use of dairy ingredients involves a certain risk, namely the allergenic potential of milk proteins. A number of methods have been developed to detect milk-origin raw materials in foodstuffs, including immunological reference methods. This study presents newly developed immunohistochemical (IHC) methods for casein detection in meat products. Casein was successfully detected directly in meat products where sensitivity was determined at 1.21 and specificity at 0.28. The results obtained from the IHC were compared with the Enzyme-Linked Immuno Sorbent Assay (ELISA) and there was no statistically significant difference between the IHC and ELISA methods (p &gt, 0.05). The correspondence between the methods was 72% in total. The highest correspondence was reached in frankfurters (90%), the lowest in canned p&acirc, t&eacute, (44%).

In meat products, mechanically separated meat (MSM) is often used as a raw material. Usage of MSM has economic benefit for meat industries and height utilization of animal raw material. In opposite is consumer concern for height quality of meat products. In order to detect MSM, invasive/destructive methods are mainly used and their nature is largely based on demonstrating the accompanying substances or structures. This paper describes a new non-invasive method to detect bone fragments as accompanying structures of MSM and it is based on X-ray micro computed tomography (μCT). μCT method was tested on a cooked meat product containing 50% of MSM. Bone tissue detected based on the higher density via μCT was confirmed by the image analysis and histochemical method using alizarin red staining which is used for detection of bone tissue. The μCT method was verified as a suitable non-destructive method to analyze bone fragments in meat products with the possibility to determine their shape parameters.

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 Tukey's 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. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

This research aimed to evaluate the impact of different salts on dough rheology parameters and gas cell development during dough preparation. Three types of salts in four concentrations each were used in dough preparation and following analyses were conducted: sodium content, salt structure analysis, dough hardness, dough stickiness and dough image analysis. The research showed how significantly (p

Multiple factor analysis was used to examine naturally white, mature and spreadable bryndza cheese varieties. Sensory and physiochemical properties were evaluated during storage in vacuum and non-vacuum packed conditions at 4 ± 2°C. The results of statistical method showed similarity in varieties made from pasteurized ewe milk and mixed bryndza cheese before and after storage at both package conditions (p

Studies dealing with the development of edible/biodegradable packaging have been gaining popularity since these commodities are marked as being ecofriendly, especially when byproducts are incorporated. Consequently, this study aimed at the development of chitosan-based coatings with plant byproducts. Their sensory properties, colour attributes, occurrence of cracks in microstructure and biodegradability were analysed. Coatings containing grape and blueberry pomace had statistically significantly (p &lt, 0.05) higher levels of colour intensity. Coating samples were characterised by lower aroma intensity (3.46–4.77), relatively smooth surface (2.40–5.86), and low stickiness (2.11–3.14). In the overall hedonic evaluation, the samples containing parsley pomace in all concentrations and a sample containing 5% grape pomace achieved a statistically significantly (p &lt, 0.05) better evaluation (5.76–5.93). The lowest values of the parameter ΔE2000 were recorded for the sample containing 5% parsley pomace (3.5), the highest was for the sample with 20% blueberry pomace (39.3). An analysis of the coating surface microstructure showed the presence of surface cracks at an 80 K magnification but the protective function of the edible coating was not disrupted by the added plant pomace. The produced samples can be considered to have a high biodegradability rate. The results of our experimentally produced coatings indicate their possible application on a commercial scale.

Gliadin is a major allergen causing allergies occurring also in meat products. Since wheat protein is used as a meat substitute to reduce cost of meat products. Sensitive consumers of these products are really threatened by food allergies in different allergic reaction. The objective of the study was to compare the histochemical, immunochemical (ALERT gliadin screening test) and immunofluorescence methods for the detection of wheat protein in model meat samples and meat products. The limit of detection for the ALERT gliadin screening test was 10 × 104 mg kg−1 of addition, while the histochemical method demonstrated concentration of wheat protein already from 10 × 103 mg kg−1, and the immunofluorescence method from the concentration of 20 mg kg−1. Comparison of the methods using McNemar’s test shows a statistically highly significant difference (p = .01) between the immunofluorescence method and ELISA and a statistically highly significant difference (p = .01) between the immunofluorescence and his...

The aim of the study was to analytically evaluate quantum dots in immunohistofluorescence (IHF-QD) microscopic imaging as detectors of food allergens&mdash, peanut and wheat. The experiment was designed as two in silico experiments or simulations: (a) models of pastry samples were prepared with the addition of allergenic components (peanut and wheat protein components) and without the addition of allergenic components, and (b) positive and negative commercial samples underwent food allergen detection. The samples from both simulations were tested by the ELISA and IHF-QD microscopic methods. The primary antibodies (secondary antibodies to a rabbit Fc fragment with labeled CdSe/ZnS QD) were labelled at 525, 585, and 655 nm emissions. The use of quantum dots (QDs) has expanded to many science areas and they are also finding use in food allergen detection, as shown in the study. The study indicated that differences between the ELISA and IHF-QD microscopic methods were not observable among experimentally produced pastry samples with and without allergenic components, although differences were observed among commercial samples. The important value of the study is certainly the differences found in the application of different QD conjugates (525, 585, and 655). The highest contrast was found in the application of 585 QD conjugates that can serve for the possible quantification of present food allergens&mdash, peanuts and wheat. The study clearly emphasized that QD can be used for the qualitative detection of food allergens and can represent a reliable analytical method for food allergen detection in different food matrixes.

Geographical and botanical origin of honeys can be characterized on the basis of physico-chemical composition, sensory properties and on the basis of melissopalynological analysis. No comprehensive description of the characteristics of Czech honey has been published so far. This study provides insights that are important for correct classification. The study analysed 317 samples of authentic honey from randomly selected localities. Due to the diversity of the landscape, the typical honey of the region is blend honey with a predominance of blossom honey. According to the pollen profile and electric conductivity, the honeys were sorted into the following: Brassica honey (BH), Floral honey (FH), Fruit tree honey (PH), Honeydew (HD), Lime tree honey (LH), Robinia pseudoacacia honey (RH), and Trifolium honey (TH). Physico-chemical properties, including higher carbohydrates, were determined for the honeys and their pollen profiles were examined. The physico-chemical properties and pollen profile are partially in compliance with the description of European monofloral honeys, except for RH and TH. Although they had the highest proportion of acacia pollen, amounting to &gt, 10% of all the Czech honeys, these RH honeys differ from the European standard, so they cannot be considered acacia honey. Further, PH honeys and FH polyfloral honeys were described. Most honeys contained a significant proportion of rapeseed pollen, which is one of the common agricultural crops grown in the Czech Republic. All the analysed honeys met the parameters defined by the legislation. Due to direct on-site sampling, honeys were characterized by a low 5-(hydroxymethyl)furfural (HMF) content (3.0 mg/kg) and high diastase activity (24.4 DN). Honeydew honeys had the highest proportion of higher carbohydrates, primarily of Melezitose (4.8 g/100 g) and Trehalose (1.3 g/100 g). The presence of higher carbohydrates was also confirmed in LH for Maltose (4.6 g/100 g) and Turanose (2.4 g/100 g).

Fat is an irreplacable ingredient in the production of sausages and it determines the appearance of the resulting cut to a significant extent. When shopping, consumers choose a traditional product mostly according to its appearance, based onwhat they are used to. Chemical analysis is capable to determine the total fat content in the product, but it cannot accurately describe the shape and size of fat grains which the consumer observes when looking at the product. The size of fat grains considered acceptable by consumers can be determined using sensory analysis or image analysis. In recent years, image analysis has become widely used when examining meat and meat products. Compared to the human eye, image analysis using a computer system is highly effective, since a correctly adjusted computer program is able to evaluate results with lower error rate. The most commonly monitored parameter in meat products is the aforementioned fat. The fat is located in the cut surface of the product in the form of dispersed particles which can be fairly reliably identified based on color differences in the individual parts of the product matrix. The size of the fat grains depends on the input raw material used as well as on the production technology. The present article describes the application of image analysis when evaluating fat grains in the appearance of cut of the Gothaj sausage whose sensory requirements are set by Czech legislation, namely by Decree No. 326/2001 Coll., as amended. The paper evaluates the size of fat mosaic grains in Gothaj sausages from different manufacturers. Fat grains were divided into ten size classes according to various size limits; specifically, 0.25, 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 5.0, 8.0 and over 8 mm. The upper limit of up to 8 mm in diameter was chosen based on the limit for the size of individual fat grains set by the legislation. This upper limit was not exceeded by any of the products. On the other side the mosaic had the hightest representation of 0.25 mm fat grains.

In recent years, various protein additives intended for manufacture of meat products have increasing importance in the food industry. These ingredients include both, plant-origin as well as animal-origin proteins. Among animal proteins, blood plasma, milk protein or collagen are used most commonly. Collagen is obtained from pork, beef, and poultry or fish skin. Collagen does not contain all the essential amino acids, thus it is not a full protein in terms of essential amino acids supply for one's organism. However, it is rather rich in amino acids of glycine, hydroxyproline and proline which are almost absent in other proteins and their synthesis is very energy intensive. Collagen, which is added to the soft and small meat products in the form of isolated porcine protein, significantly affects the organoleptic properties of these products. This work focused on detection of isolated porcine protein in model meat products where detection of isolated porcine protein was verified by histological staining and light microscopy. Seven model meat products from poultry meat and 7 model meat products from beef and pork in the ratio of 1:1, which contained 2.5% concentration of various commercially produced isolated porcine proteins, were examined. These model meat products were histologically processed by means of cryosections and stained with hematoxylin-eosin staining, toluidine blue staining and Calleja. For the validation phase, Calleja was utilized. To determine the sensitivity and specificity, five model meat products containing the addition of isolated porcine protein and five model meat products free of it were used. The sensitivity was determined for isolated porcine protein at 1.00 and specificity was determined at 1.00. The detection limit of the method was at the level of 0.001% addition. Repeatability of the method was carried out using products with addition as well as without addition of isolated porcine protein and detection was repeated 10 times. Repeatability in both, positive and negative samples, for isolated porcine protein was determined at 100%. The results show that the histological processing of cryosections stained using Calleja is suitable for detecting isolated porcine protein in meat products.

The aim of this study was to analyse pig muscles used in the production of cooked hams with a view to the occurrence of PSE-type defects and their potential effect on the frequency of destructured zones in finished products. One hundred and six samples of m. adductor (AD) and m. semimembranosus (SM) pig muscles were studied. The two kinds of muscle differed from each other in terms of their pH values and colour (L⁎: lightness, a⁎: redness, and b⁎: yellowness); these differences between the two categories were statistically significant (P<0.001). The AD muscles were divided into meat with PSE (pale, soft, and exudative) defects and non-PSE meat by sensory examination. A total of 44.3% of AD muscles showed PSE defects. Lightness L⁎ fell within a range of 50.68–55.23 in non-PSE meat (AD) and was statistically significantly lower (P<0.001) than in PSE meat (56.25–58.78). Drip loss (AD) was higher (P<0.001) in PSE meat (4.83–6.27%) than in non-PSE meat (3.53–5.0%). Cooked hams prepared from pig muscles showed evident destructured zones when sliced, the number and overall area of which were not affected by the occurrence of PSE defects in the raw meat used.

Pospiech M., Tremlova B., Rencova E., Randulova Z., Řezacova Lukaskova Z., Pokorna J. (2011): Comparison of the results of the ELISA, histochemical, and immunohistochemical detection of soya proteins in meat products. Czech J. Food Sci., 29: 471–479. This work compares the commonly used immunochemical methods for soya protein detection and alternative microscopic methods. Immunochemical methods were represented by the competitive ELISA method. Histochemical and immunohistochemical methods were used for microscopical examination. From a group of 252 meat products, each sample was examined for soya proteins by ELISA, histochemical, and immunohistochemical methods. The products came from the following categories: cooked sausages, ham, dry cooked sausages, and fermented sausages. The results showed that the highest accuracy was achieved by immunohistochemical examination. However, in the category of cooked sausages, this result was not statistically significant. Since the results in the individual categories differed, our results demonstrate that one single method does not always provide reliable and completely objective results. Immunohistochemical methods seem to be the most suitable for the verification of the reference immunochemical method results and prevention of false results.

Randulova Z., Tremlova B., Řezacova-Lukaskova Z., Pospiech M., Straka I. (2011): Determination of soya protein in model meat products using image analysis. Czech J. Food Sci., 29: 318–321. The addition of plant proteins into meat products is nowadays a commonly used practice especially for the technological and economical reasons. Their properties have been known and used in meat products production for a long time. In the past, wheat protein or flour had been used most frequently, however, in these days they are being replaced by soya protein which has much more favourable properties in its use. Considering the possible misuse of raw materials of plant origin for the adulteration of meat products, the existence of highly sensitive and accurate procedures for their detection is needed including the determination of their content. Soya protein can be detected using various methods. In our work, an immunohistochemical method was used with image analysis for the quantification of soya protein. Model meat products with the addition of known amounts of soya protein in various forms were made for

The study focused on the optimisation of immunohistochemical examination for gluten content detection in model samples (pork meat with wheat semi-smooth flour, pork meat with wheat protein edible vital). The best results were achieved with immunohistochemical method based on ABC (avidin-biotin complex) method utilising polyclonal antibodies diluted 1:1000. The results demonstrate that for pure wheat protein detection, the utilisation of immunohistochemical detection, which can detect as little as 0.1% of the added wheat protein, is more advantageous, while the commonly used ELISA method reliably proves this additive approximately from 0.4% upwards.

Pospiech M., Tremlova B. , Rencova E. , Randulova Z. (2009): Immunohistochemical detection of soya protein - optimisation and verification of the method . Czech J. Food Sci., 27: 11-19. A functional immunohistochemical method for soya proteins detection was developed. The procedure is based on the avidin-biotin complex (ABC) method that attains sufficient sensitivity. The method was verified by the analysis of the model samples of different forms of soya additives containing various concentrations of soya isolate. The detection limit of soya present in the model samples was 0.5%. Different possibilities of the background staining were tested. The best results were obtained with the background staining according to Calleja. The results were confirmed by the accredited indirect ELISA method. The method allows the identification of various forms of soya proteins such as isolates, texturates, concentrates, and flour.