Potravinarstvo Slovak Journal of Food Sciences
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Modeling of urease thermal inactivation processes in soybean at high-temperature micronization
Get PDFThe use of soybean, in particular in forage production without preliminary heat treatment is not appropriate, and sometimes dangerous, because of the presence of antinutrients. As a marker in assessing safety of cakes and meals, there is often used urease in forage production. This paper describes the results of thermal inactivation of urease in soybean during the process of high-temperature micronization (heating of grain in the flux of infrared radiation). There have been obtained the empirical dependencies of the degree of its inactivation on time of heat treatment and energy exposure (the product of irradiation by the time of treatment). The similar dependences of urease activity on grain temperature are invariant to infrared heating (irradiation and time) regimes, but their nature is affected by the initial moisture content. The paper proposes the models of inactivation of antinutrients based on of the first-order equations of chemical kinetics with the reaction rate constant in various forms (Arrhenius and Hinshelwood, the transition state theory). The models have been tested on literature data on the inactivation of a trypsin inhibitor at a constant temperature. The models are further refined taking into account the variable (increasing) temperature and are reduced to the simplest form: Y= k [Exp (-εR/T) - T0 еxp (-εR/T0)], where T, T0- are the current and initial temperatures of grain, k, εR - theempirical coefficients. The identification of the model coefficients was carried out based on the results of inactivation of urease during heating in the flux of infrared radiation. It has been established that the results of thermal inactivation of soybean do not depend on the IR processing regimes and are determined only by the initial moisture content of grain, and by the end heating temperature. The efficiency of inactivation is higher the higher is the used irradiation. There is a compensating effect - with the growth in one coefficient, another is also increased. The considered models can be used for the thermal degradation processes and other thermolabile substances
Assessment of the functional quality and safety of yoghurts produced with starter cultures obtained from selected commercially sold yoghurts
Get PDFThe study focused on the examination of laboratory prepared yoghurts which were fermented with selected starter cultures from commercially sold yoghurt. The starter cultures were molecularly identified (16s rRNA) as Enterococcus lactis, Lactobacillus plantarum, Lactobacillus pentosus, Pediococcuspentosaceus and Enterococcus durans. The isolates were examined for bile tolerance as an indicator of their ability to survive in the gut. The starter cultures were used to produce different yoghurts in the following order: Enterococcus lactis produced yoghurt, L. plantarum and L. pentosus produced yoghurt, Pediococcuspentosaceus produced yoghurt, E. durans produced yoghurt and yoghurt produced with all starter cultures. All yoghurts were examined for nutritional quality (vitamin A, B12 and C content, soluble and casein bound magnesium and calcium and proximate nutrient composition). At p ≤0.05, there was statistical significant difference in the nutritional content with P. pentosaceus contained yoghurt, E. durans contained yoghurt and yoghurt produced with a combination of all isolates recording the highest nutritional values and the lowest was observed with the control. Safety tests such as haematology and histology were carried out on wistar rats. After 7 days of feeding the rats in groups with the different yoghurts and a control without yoghurt, there were marked improvements in the red blood cell counts, white blood cell counts but no significant difference in the differentials at p ≤0.05. The isolates were also observed to have no disruptive effect on the morphology and structure of the small intestine. Overall, the use of these lactic acid bacteria strains showed immense benefits in their use as starter cultures and the study demonstrated safety of the final products for consumption
Bovine mucous membranes as a source of antimicrobial compounds
Get PDFLoss of food quality, deterioration of organoleptic properties and accumulation of anti-alimentary compounds are in focus of modern food science. Nowadays, such traditional methods as processing, physical and chemical treatment are used for improving of shelf life. An alternative ways of shelf life increasing are quite a sharp problem. Antimicrobial peptides (AMPs) could be an actual alternative. According to Antimicrobial Peptide Database (http://aps.unmc.edu/AP/main.php), 2884 antimicrobial peptides from six kingdoms were found and identified. Mucous membranes of farm animals due to their border position and intensive contact with different pathogens could be a capacious source of such substances. Objects of the study were bovine oral cavity mucosa, nasal cavity mucosa, tracheal cavity mucosa, rectal mucosa, tongue mucosa, saliva gland and submandibular lymph nodes. Two-dimensional electrophoresis (2DE) was performed according to the method of O'Farrell, 35 protein fractions were identified by MALDI-TOF MS and MS/MS mass spectrometry. A number of qualitative and quantitative differences were revealed. A large number of histones (H2bd-like, H2BC, HIST1H2BD, HIST2H2AC, HIST1H2AH, histone H3.3 and H2bl-like, HIST2H2AC and histone H3.3, mixture HIST1H2AJ, HIST2H2BE and histone H2A type 2-C) were found in all mucous membranes as well as several tissue-specific proteins (proteins S100-A12 and AGR2, isoforms of ribosomal proteins, myelin P2, odorant-binding protein, secretoglobin), which could be a precusors of bioactive peptide
Studying the impact of non-traditinal supplements on the quality of the minced rabbit meat products
Get PDFThe topical challenge of our era is the development of such compositions of innovative polyfunctional products, which take into account, to the maximum degree, the effect of mutual enrichment of animal and vegetable products, physiological substances, the capacity of dietary fibers to remove harmful substances from the body and the capacity of probiotics to maintain micro-ecological balance in the gastro-intestinal tract. One of the priority areas of the implementation of these issues the development of technologies of rabbit meat products fortified with plant raw materials and prebiotic ingredients. The purpose of the work is to study the impact of vegetable supplements and lactulose on the quality of the minced meat products. When performing this work, there were used the modern, standard, commonly accepted methods of research, which are in compliance with solving the set objectives. Statistical processing of the results obtained and the evaluation of the reliability of data were carried out by the mathematical statistics methods using the IBM SPSS Statistics for Windows. There have been studied the chemical compositions of the brush rabbit meat bred in Georgia, as well as of haricot bean, pea and amaranth. It is reasonable to use the above-mentioned plant raw material and lactulose use as bioactive supplemented in the production of animal products. There has been justified the appropriateness of mentioned plant raw materials and lactulose as the bio-correcting supplements in the technology for producing animal food products. In order to control and identify the functionality of products, there have been identified the critical control points, such as: preparing and dosing functional raw materials, the introduction stages and an equal distribution of formula components. There have been established the hydration conditions and modes of haricot bean, pea and amaranth flours. There are shown the advantages of their hydration in mineral water, the optimal irrigation modulus has been determined. Also, there have been determined the maximum permissible levels of vegetable supplements and lactulose to be added into the minced rabbit meat, which have a positive impact on the functional-technological properties of semi-finished and finished products, in particular, improve the water binding and water holding capacities of the minced meat, increase the yield of product, as well as improve organoleptic indices of its quality, in comparison with a reference sample. Based on the study of the microbiological characteristics of developed products, it has been demonstrated that the number of mesophilic-aerobic and facultative-anaerobic microorganisms does not exceed the sanitary norms and standards, no E. coli group bacteria and pathogenic microorganisms were detected, including Salmonella that is in line with the microbiological safety hygienic requirements and norms. The obtained data set indicates the appropriateness of using a new type of product in a functional, dietetic and preventive nutrition
Attention analysis of honey jar labels using eye-tracking techniques
Get PDFHoney represents not just a specific product of animal origin, which's major part are plant products, but also the oldest sweetener of human kind. It is actually a sweet substance produced by beetles from nectar plants or from insects excreted on plants. Because of many different reasons (e.g. for trading, handling, storage), in the history of mankind, there have been introduced different forms of packaging and protective means through which this precious product could be protected. The present paper addresses consumer behaviour, focusing on the influence of packaging and labelling on young consumers aged from 20 to 35 years, especially when choosing honey. The realization of the main aim is conditional on meeting the following partial objectives - to identify the basic elements appearing on two samples of honey packaging and their impact on consumer perception, respectively to identify the differences in the perception of individual elements of the packaging, based on the respondents' gender. In the present paper, there are used different marketing research techniques, specifically the eye-tracking observation. The experiment involved exactly 12 samples of honey and finally 35 participants (18 women and 17 men). Based on the results of the authors' own work, it can be stated that the most eye-catching aspects of honey packaging are the producer's brand, as well as the variety description and name given to the honey. The least noticed aspects are the weight details of the packaging and the graphic design
Garlic (Allium sativum L.) - the content of bioactive compounds
Get PDFGenus Allium belongs to the family Alliaceae, which contains more than 600 species. Garlic (Allium sativum L.) is the most popular food ingredient widely used all over the world. During the last few decades, garlic has received tremendous attention for their wide range of therapeutic properties and great health benefits. Garlic has possessed antibacterial, antifungal, antiparasitic, antiviral, antioxidant, anticholesteremic, anti-cancerous, and vasodilator characteristics. In this work the total polyphenols content, total sulfur content and antioxidant activity was compared and evaluated in four studied varieties of garlic (Mojmír, Lukan, Záhorský and Makoi). The analyzed samples of garlic were collected at the stage of full maturity in the area Bardejov. The total polyphenols content was measured using the spectrophotometric method of Folin-Ciocalteu agents. The total polyphenols content in studied varieties of garlic were determined in the range 612.23 mg.kg-1 (Mojmír) to 566.01 mg.kg-1 (Lukan). The total polyphenols content in garlic can be arranged as follows: Mojmír >Makoi >Záhorský >Lukan. The determination of the total sulfur content is based on dry combustion in the presence of oxygen and allows for the quantitative conversion of sulfur to SO2. Statistically significant highest level of total sulfur content was recorded in 0.638% (Mojmír) and the lowest level was in 0.421% (Makoi). According to determined values of total sulfur content the studied varieties of garlic can be arranged in the following order: Mojmír >Lukan >Záhorský >Makoi. Antioxidant activity was determined by the spectrophotometric method using a compound DPPH (2.2-diphenyl-1-picryhydrazyl). The highest value of antioxidant activity was measured in Mojmír (15.24%). The lowest level was observed in Makoi (11.73%). The antioxidant activity in garlic declined in the following order: Mojmír >Lukan >Záhorský >Makoi. In all studied samples of garlic was confirmed by the strong dependence of the total polyphenols content, total sulfur content and antioxidant activity
Mineral composition of amaranth (Amaranthus L.) seeds of vegetable and grain usage by ARHIVBSP selection
Get PDFThe questions of the practical usage of the analytical scanning electron microscope JSM 600 LA by JEOL company (Japan) with EDS system - microanalysis for the studying of the ash elemental composition of seeds 9 breeds (Vegetable and Grain application) 4 species genus Amaranthus L. - A. hypochondriacus, A. cruentus, A. hybridus, A. caudatus, A. tricolor. Plant seeds by Federal center of vegetable production selection were envisaged. We studied the concentration of 14 basic elements (in weight %) contained in the mineral part of amaranth seeds. In the amaranth seeds of vegetable forms the accumulation order of the elements is the following: Ca >K >P >Mg >Si >Se >Fe >Mo ≈ S ≈ Cl ≈ Zn >Na >Al. In the seeds of the grain forms the order is different: К >P >Ca >Si >Se >Mg >Fe >Na >Mo >Cl ≈ S ≈ Mn ≈ Zn ≈ Al. The amaranth seeds of the grain forms are rich in macro - and microelements. P, K, Cl and S in the seeds of the grain forms are accumulated on 50, 37, 15 and 5% more and Si, Fe and Al in 2.6 and 1.8 times more than in the vegetable forms seeds. The breeds with the high concentration of the elements are recommended for using in the selection process. The elevated level of the essential macro- and microelements such as Ca, K, P, Mg, Mo, S and Cl stipulates the perspective of the functional products creation on the base of the studied amaranth seeds for the enrichment of the food stuffs
Thermal aging of edible oils: spectrophotometric study
Get PDFThe aim of the present study was to determine the spectrophotometric and thermal aging properties of various edible oils (olive, peanut, rapeseed, soybean and sunflower oils) which are commonly available in the Czech market. The samples were measured by UV/VIS absorption spectrometry and fluorescence spectroscopy. Detected substances of UV/VIS spectra were compared to expected oil composition; the highest absorbance values were detected in a wavelength range 300-550 nm which can be related to the presence of unsaturated fatty acids. The mixtures of oils were characterized by fluorescence spectroscopy; the individual oils were successfully distinguished according to their excitation-emission profiles. This method was also used to detect the samples of adulterated oils, i.e., the adulteration of high-quality oils with soybean oil. From a physicochemical point of view, the influence of temperature on the compounds of extra virgin olive oil was examined by thermal stress simulation. This thermal aging analysis demonstrated that the amount of oxidation products in olive oil increased during the heating whereas the chlorophyll content decreased. The results showed the ability of the techniques used, UV/VIS absorption spectrometry and fluorescence spectroscopy, to characterize the quality and composition of oils, and to distinguish individual oils in blends. UV/VIS spectrometry was also successfully employed for the evaluation of olive oil qualitative parameters according to the standard quality parameters by the "International Olive Council" (EEC 702/2007)
Study of polymorphism of maize using dna and protein markers
Get PDFIn the present investigation 40 genotypes of maize from Czechoslovakia, Hungary, Poland, Union of Soviet Socialist Republics, Slovakia and Yugoslavia were analysed using 20 start codon targeted (SCoT) markers, 10 simple sequence repeat (SSR) markers, 13 random amplified polymorphic (RAPD) markers and using SDS-PAGE markers. Twenty SCoT primers produced 114 DNA fragments with an average of 5.7 bands per primer. Out of the total of 114 amplified fragments, 86 (76.43 %) were polymorphic, with an average of 4.30 polymorphic bands per primer. Ten SSR primers revealed a total of 65 alleles ranging from 4 (UMC1060) to 8 (UMC2002 and UMC1155) alleles per locus with a mean value of 6.50 alleles per locus. 20 SCoT primers produced total 114 fragments across 40 maize genotypes, of which 86 (76.43 %) were polymorphic with an average of 4.30 polymorphic fragments per primer and number of amplified fragments ranged from 2 (SCoT 45) to 8 (SCoT 28 and SCoT 63). The number of total scorable protein bands was twentythree as a result of SDS-PAGE technique but those that were not cosistent in reproducibility and showed occasional variation in sharpness and density were not considered. Based on these bands forty accessions of maize were screened. Out of twentythree polypeptide bands, 6 (31%) were commonly present in all accessions and considered as monomorphic, while 17 (65%) showed variations and considered as polymorphic. The dendrogram of 40 old maize genotypes based on SSR, SCoT, RAPD and SDS-PAGE markers using UGMA algorithm was constructed
Thermo-mechanical properties of dough enriched with wheat bran from different wheat variety
Get PDFWheat bran is the by-product derived from the wheat milling and represents a good source of dietary fiber. Consumption of wheat bran is associated with many health benefits. The hydration properties (water holding, water retention and swelling capacity) and oil binding capacity of bran from various wheat variety were investigated. It was showed that the water holding capacity of bran ranged from 2.27 to 2.98 g.g-1, which were approximately four times higher compared to wheat flour. Also, it was observed that commercial wheat bran was characterised with the highest swelling capacity (5.21 mL.g-1) and the lowest water retention and oil binding capacities (1.38 and 1.35 g.g-1, respectively). Mixing and pasting properties of wheat dough with addition of bran at different level (5, 10 and 15%) were studied using Mixolab. From the results it was concluded that water absorption and dough development time increased with addition of different bran, while dough stability decreased. Moreover, with increasing addition level of different bran significantly affected the thermo-mechanical properties of wheat dough. The lowest effect on protein weakening was found after addition of spelt bran. The higher starch pasting ability of enriched dough was recorded after incorporation of bran from crossbreed Lubica. Furthermore, it was found that dough enriched with the commercial wheat bran was characterized by the lowest values of C3 (lower starch pasting ability), C4 (lower stability of hot formed gel) and C5 (lower starch retrogradation) parameters.