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Results 181 to 210 of 380:

Influence of different essential oils on refrigerated fish patties produced from bonito fish (Sarda sarda Bloch, 1793)Food Analysis, Food Quality and Nutrition

Husnu Sahan GURAN, Gulsum OKSUZTEPE, Ozlem Emir COBAN, Gokhan Kursad INCILI

Czech J. Food Sci., 2015, 33(1):37-44 | DOI: 10.17221/188/2014-CJFS

The effects of different concentrations of thyme (group T), clove (group Cl), and rosemary (group R) extracts on the microbiological, chemical, and sensory attributes of fish patty made from the bonito fish (Sarda sarda Bloch, 1793) were investigated. The numbers of total mesophilic aerobic bacteria, coliform bacteria, Staphylococcus-Micrococcus spp. and yeasts and moulds in group R were lower than those of the other groups during storage (P < 0.05). During the storage period, total volatile basic nitrogen (TVB-N), thiobarbituric acid index (TBA-i), peroxide values, and free fatty acid content gradually increased in all groups, and significant differences were found between the groups (P < 0.05). The results of sensory evaluation showed that the shelf life of fish patties was 4 days for the control group, and 8, 10, and 14 days for the groups treated with thyme, clove and rosemary essential oil, respectively (P < 0.05). In conclusion, the addition of essential oils showed a positive effect on the product shelf-life; and in particular, rosemary essential oil produced a remarkable effect.

Analysis of chemical and sensory parameters in different kinds of escolar (Lepidocybium flavobrunneum) productsFood Analysis, Food Quality and Nutrition

Hana BUCHTOVÁ, Đani ĐORĐEVIĆ, Stanislav KOČÁREK, Petr CHOMÁT

Czech J. Food Sci., 2015, 33(4):346-353 | DOI: 10.17221/435/2014-CJFS

The chemical composition (nutritional and freshness parameters) and sensory characteristics were evaluated of escolar (Lepidocybium flavobrunneum) defrosted raw fillets and steaks that were marinated differently (pepper, onion, chilly, herbs, knusper, and hot) and packaged in a manner suitable for microwave heating (Darfresh® Simple Steps®). The study was carried out by using 8 skinless fillets of Lepidocybium flavobrunneum. The selected 18 parameters, i.e. dry matter/moisture, crude protein, net protein, collagen, net muscle protein, lipid, ash, saccharide, energy value, pH, water activity, salt content, total volatile basic nitrogen, trimethylamine, free fatty acids, peroxide value, and thiobarbituric acid assay were evaluated. The results indicate that the sample of Chilly marinated steaks was evaluated as the best one (90.29 ± 9.82), however, the samples of Herbs (89.6 ± 13.89) and Knusper (88.64 ± 15.59) marinated steaks also received more than 85 points for the overall impression. Control sample received the smallest number of points (71.7 ± 26.54) for the overall impression.

Effect of slurry incorporation into retentate on proteolysis of Iranian ultrafiltered white cheeseFood Technology and Economy, Engineering and Physical Properties

Rahele Nezhad Razmjoui Akhgar, Javad Hesari, Sodeif Azadmard Damirchi

Czech J. Food Sci., 2016, 34(2):173-179 | DOI: 10.17221/361/2015-CJFS

The effect of addition of ripened cheese slurry into retentate on the proteolysis of Iranian ultrafiltered cheese was investigated during 60-day ripening. No significant differences were found in gross composition between experimental samples, however, pH values were significantly higher (P > 0.05) in slurry-containing cheese. Urea-polyacrylamide gel of the pH 4.6 insoluble fractions showed that αs1-casein was hydrolysed more rapidly than β-casein. There was no significant difference in the hydrolysis rate of αs1- and β-casein between the two cheeses. The levels of water soluble nitrogen were significantly higher (P > 0.05) in slurry-containing samples from day 15. The incorporation of ripened slurry into retentate influenced the peptide profiles obtained by RP-HPLC of the pH 4.6-soluble fractions of the cheeses. The ratio of hydrophilic to hydrophobic peptides was higher in slurry-containing cheese. Total and individual free amino acids were significantly higher (P > 0.05) in cheeses containing slurry. It was concluded that the incorporation of ripened cheese slurry into retentate has a beneficial effect on proteolysis acceleration and development of aroma and flavour in Iranian ultrafiltered white cheese.

Phosvitin phosphopeptide preparation using immobilised trypsin and enhancing calcium absorption in growing ratsFood Analysis, Food Quality and Nutrition

Qiang Zhong, Xing-Ling Li, Wei-Dong Hu, Bo Zeng, Ren-Ming Liang, Hui Liu, Zai-Xin Li, Zhi Zhang

Czech J. Food Sci., 2016, 34(4):325-331 | DOI: 10.17221/425/2015-CJFS

We demonstrate a new, efficient method for the preparation of phosvitin phosphopeptides using immobilised-trypsin enzymolysis technology. Immobilised trypsin was prepared using a covalent binding method, and then was added to degrade egg yolk phosvitin for the production of phosphopeptides. In our results, the prepared immobilised trypsin demonstrated a higher hydrolysing activity toward phosvitin than free trypsin, and the hydrolysing activity was retained well even after trypsin was repeatedly used up to five times. Interestingly, the phosvitin phosphopeptides prepared with immobilised trypsin demonstrated a lower N/P ratio and a higher calcium-binding efficiency than those prepared with free trypsin. Furthermore, phosphopeptides significantly increased the rate of calcium absorption and serum calcium content in vivo. Based on these results, we conclude that trypsin immobilised onto chitosan has a greater phosvitin hydrolysing activity than free trypsin, and the prepared phosphopeptides can be used as a new calcium supplement to significantly increase calcium absorption in growing rats.

Quality of eggs in different production systemsFood Technology and Economy, Engineering and Physical Properties

Guler Yenice, Ozgur Kaynar, Mustafa Ileriturk, Feryaz Hira, Armagan Hayirli

Czech J. Food Sci., 2016, 34(4):370-376 | DOI: 10.17221/33/2016-CJFS

This experiment was carried out to compare morphological egg quality parameters, as well as lipid and protein profiles, of brown eggs laid by chickens reared under different production systems: cage, free-range, and family type. A total of 270 brown eggs were obtained from commercial poultry companies raising Lohmann Brown laying hens in a cage system and free-range unit as well as families possessing hens in their yards. The egg lipid and protein contents, as well as lipid and protein profile, varied among the production systems. However, eggs from the free-range system had similar characteristics to those from the cage system. Quality of eggs from the family type system was quite variable. In conclusion, egg quality can be affected by the production system.

Preparation of conjugated linoleic acid enriched derivatives by conventional and biphasic isomerisationFood Chemistry and Safety

Jan Kyselka, Lukáš Thomes, Simona Remišová, Miroslav Dragoun, Markéta Berčíková, Vladimír Filip

Czech J. Food Sci., 2016, 34(6):511-521 | DOI: 10.17221/362/2016-CJFS

The preparation of conjugated linoleic acid (CLA)-enriched free fatty acids by industrial processes compared with our biphasic isomerisation experiments in a special designed reactor enabling the preparation of CLA esters was evaluated. Our experiments further revealed the main disadvantage of semi-synthetic alkali isomerisation to be the formation of conjugated E,E-octadecadienoic acid isomers (2.92-3.44%) and the bioavailability of free fatty acid products. Urea fractionation technology improved the quality of the reaction mixture, but at the same time the yield of rumenic acid was decreased on purification. Therefore, we decided to apply complexes of noble metals in order to isomerise linoleic acid ester derivatives. The known Wilkinson's hydrogenation catalyst, RhCl (PPh3)3, was found to be the most effective. We investigated the preparation of bioavailable CLA-enriched triacylglycerols. Special attention was paid to recycling of Wilkinson's catalyst.

Spent brewer's yeast extracts as a new component of functional foodFood Technology and Economy, Engineering and Physical Properties

Bartłomiej Podpora, Franciszek Świderski, Anna Sadowska, Rita Rakowska, Grażyna Wasiak-Zys

Czech J. Food Sci., 2016, 34(6):554-563 | DOI: 10.17221/419/2015-CJFS

The use of yeast extracts as a natural and valuable additive ingredient intended for the production of functional food and dietary supplements were demonstrated. The chemical composition, amino acid analysis, determination of protein molecular weights, antioxidant properties, and sensory evaluation were carried out for two yeast extracts. It was found that the tested extracts are characterised by high essential amino acid content, exceeding the levels of reference protein developed by the FAO/WHO, and high antioxidant activity. Sensory characteristics of tested extracts may favourably influence the quality of the proposed functional foods and dietary supplements. The obtained results indicate that the tested extracts can be utilised as a source of free amino acids and peptides in the design of functional foods and dietary supplements.

Quality of shiitake stipe steamed bun

Yu-Hsiu Tseng, Joan-Hwa Yang, Chi-En Lee, Jeng-Leun Mau

Czech J. Food Sci., 2011, 29(1):79-86 | DOI: 10.17221/171/2009-CJFS

Shiitake [Lentinula edodes (Berk.) Pegler] stipe was incorporated into steamed bun. Quality attributes including the specific volume, colour and sensory evaluation, and taste components in shiitake stipe steamed buns were analysed and compared with those of white steamed buns. With 2% and 5% additions of shiitake stipe flour, specific volumes of steamed buns increased by 5.8% and 5.0%, respectively. White steamed buns contained more reducing sugar, fat, and protein whereas fiber and soluble polysaccharide contents were higher in shiitake stipe steamed buns. Furthermore, shiitake stipe steamed buns contained more total soluble sugars and total free amino acids. Shiitake stipe steamed buns showed lower lightness and whiteness index values and became browner with more shiitake stipe flour added. On a seven-point hedonic scale, all sensory results were 4.07-5.80. Overall, shiitake stipe could be added into steamed bun formula to provide its beneficial health effects.

Medicinal plants of the family Lamiaceae as functional foods - a reviewReview

Klaudija Carović-Stanko, Marko Petek, Martina Grdiša, Jasna Pintar, Dalibor Bedeković, Mirjana Herak Ćustić, Zlatko Satovic

Czech J. Food Sci., 2016, 34(5):377-390 | DOI: 10.17221/504/2015-CJFS

Historically, species of the family Lamiaceae have enjoyed a rich tradition of use for flavouring, food preservation, and medicinal purposes, due to both their curative and their preventive properties. It is well known that each species has a special, complex mixture of bioactive compounds in which each component contributes to its overall bioactivity. Their value lays in the production of a wide range of secondary metabolites with potent antibacterial, antioxidant, anti-inflammatory, antimicrobial, antiviral, and anticancer activities. This review focuses on the Lamiaceae species and their secondary metabolites encompassing a wide array of beneficial functions and their applicability as sources of functional foods. It could help in addressing specific consumer needs as healthy diet is a part of the lifestyle that maintains or improves overall health.

Components responsible for antimicrobial activity of propolis from continental and Mediterranean regions in CroatianFood Microbiology and Safety

Ivana Tlak Gajger, Iva Pavlović, Mirza Bojić, Ivan Kosalec, Siniša Srečec, Toni Vlainić, Josipa Vlainić

Czech J. Food Sci., 2017, 35(5):376-385 | DOI: 10.17221/103/2017-CJFS

Propolis is a popular subject of research worldwide due to its therapeutic potential. The antimicrobial activity of propolis appears to be promising but depends on many variables related to its origin such as the content of phenolics and flavonoids. To address this issue with Croatian propolis, which has two major origins (Mediterranean and continental), we exposed bacteria (Escherichia coli and Staphylococcus aureus) and yeasts (Candida albicans and Aspergillus niger) to different propolis concentrations (two-fold microdilution method with TCC/formazan endpoint). Total phenolic and flavonoid content and chromatographic profile along with antioxidant activity were assessed. The majority of the 24 propolis samples tested exhibited potent antimicrobial activity against S. aureus bacteria and the yeast C. albicans. Most propolis samples also exhibited robust antioxidative capacity which correlated polyphenol and flavonoid content. To the best of our knowledge this is the first study in which the antimicrobial activity of Croatian propolis is correlated with its constituents.

Geographical origin of honey from eight sub-regions of Bosnia and HerzegovinaFood Analysis, Food Quality and Nutrition

Vildana Alibabić, Melisa Oraščanin, Nada Vahčić

Czech J. Food Sci., 2017, 35(6):488-495 | DOI: 10.17221/82/2017-CJFS

Principal component analysis (PCA) and cluster analysis (CA) were used to define the geographical origin of three types of monofloral (chestnut, linden, and acacia), two types of multifloral (meadow and mixed), and forest honey produced over two consecutive harvest seasons in the Una-Sana Canton (Bosnia and Herzegovina), which is geographically divided into eight sub-regions. Statistical analysis was applied to the measurement of physico-chemical and sensory parameters, as well as micro- and macronutrient (K, Na, Mg, Zn, Fe, Mn, and Al) content, along with some heavy metals (Cd, Pb, and As). Using the PCA method the characteristic parameters for all eight sub-regions were determined, while the CA grouping method was used to determine the characteristic parameters for six sub-regions. Chestnut honey is predominantly found in Cazin, chestnut and linden honey in Bosanska Krupa, chestnut and acacia honey in Bužim, acacia honey in Sanski Most, mixed honey in Velika Kladuša and forest honey in Ključ.

Qualitative properties of pasta enriched with celery root and sugar beet by-productsFood Technology and Economy, Engineering and Physical Properties

Lucia MINAROVIČOVÁ, Michaela LAUKOVÁ, Zlatica KOHAJDOVÁ, Jolana KAROVIČOVÁ, Dominika DOBROVICKÁ, Veronika KUCHTOVÁ

Czech J. Food Sci., 2018, 36(1):66-72 | DOI: 10.17221/242/2017-CJFS

The effects of wheat flour replacement at different levels (5, 7.5, 10, and 20%) by celery root and sugar beet pulp powder on rheological parameters and quality properties of enriched pasta were studied. Sensory evaluation was also investigated. Incorporation of fibre powders increased water absorption and prolonged dough stability and dough development time. Enriched pasta had higher moisture content than control pasta. Addition of fibre powders also modified the cooking quality of pasta (cooking loss and water absorption were increased and optimal cooking time was reduced). Moreover cooked pasta with the higher addition level of celery root powder was characterised by higher intensity of vegetable taste and had pleasant flavour and colour. Sensory evaluation showed that pasta with the addition of 7.5% celery root powder was the most acceptable for assessors.

Determining the optimal method for DNA isolation from fruit jamsFood Microbiology and Safety

Tereza SOVOVÁ, Barbora KŘÍŽOVÁ, Jaroslava OVESNÁ

Czech J. Food Sci., 2018, 36(2):126-132 | DOI: 10.17221/340/2017-CJFS

DNA extraction is a crucial step in PCR analysis especially when analysing food samples that can be degraded and can potentially contain PCR-inhibiting substances. In this study, we compared the suitability of three DNA extraction methods - two kits: DNeasy® Plant Mini Kit and NucleoSpin® Food, and the CTAB method - for DNA extraction from commercial fruit jams. Fourteen jams with different contents of fruit, sugar and other additives were extracted in triplicate using the above-mentioned methods directly and after a washing step. The concentration and optical density were analysed using UV spectrophotometry and the amplifiability of the obtained DNA was evaluated using a PCR assay targeting a sequence coding for chloroplast tRNA-Leu. Samples isolated using the NucleoSpin® Food kit contained non-amplifiable DNA in eight cases, and samples isolated using the CTAB method could not be quantified. The DNeasy® Plant Mini Kit thus proved to be the most suitable method, since well-amplifiable DNA was obtained for all the analysed samples.

Biochemical changes of Iranian probiotic Lighvan cheeseFood Technology and Economy, Engineering and Physical Properties

Alireza SHAHAB LAVASANI

Czech J. Food Sci., 2018, 36(2):181-186 | DOI: 10.17221/453/2016-CJFS

Lighvan cheese from ewe and goat milk was produced according to a traditional protocol, and with the addition of 9 log10 cfu/g fresh cells of Bifidobacterium lactis subsp. animalis. Probiotic Lighvan cheese was studied to determine the survival of B. lactis subsp. animalis and biochemical changes during 60 days of ripening of probiotic Lighvan cheese. Lipolysis level and organoleptic assessments were analysed. B. lactis subsp. animalis cells survived in cheese samples at concentrations up to 6.84 log10 cfu/g for at least 60 days of storage time. The lipolysis level increased continuously until the end of the ripening period.The ripening stage was the main factor affecting the cheese sensory properties.

Effect of modified atmosphere packaging on the shelf life of chilled Ccommon carp (Cyprinus carpio) steaks: chemical and sensory attributesFood Analysis, Food Quality and Nutrition

Jelena BABIĆ MILIJAŠEVIĆ, Milan MILIJAŠEVIĆ, Danijela VRANIĆ, Jasna ĐINOVIĆ STOJANOVIĆ, Slobodan LILIĆ, Vladimir KORIĆANAC

Czech J. Food Sci., 2018, 36(3):221-226 | DOI: 10.17221/195/2017-CJFS

The effect of modified atmosphere packaging (MAP 1 - 80% O2 + 20% CO2 and MAP 2 - 90% CO2 + 10% N2) on selected chemical and sensory parameters of common carp steaks stored at 3 ± 0.5°C, and determination of the shelf life of the products was studied in this research. Samples were analysed on day 1, 3, 5, 7, 9, 11, 13, 15, and 17. An increase in TVB-N values in carp steaks followed the order: MAP 2 < control < MAP 1. From day 9 of storage FFA concentrations were higher (P < 0.01) in MAP 2 samples compared to control and MAP 1 samples. The presence of oxygen (MAP 1 and control) resulted in an increase in TBA values in comparison with samples packaged in the absence of oxygen. According to sensory evaluation, it was concluded that carp steaks packaged in modified atmosphere with 80% O2 + 20% CO2 remained acceptable up to 15 days of storage, whereas samples packaged under 90% CO2 + 10% N2 as well as samples kept on flaked ice remained unchanged until the end of the experiment.

Phytochemical changes in mango fruit in response to Alternaria alternata infectionFood Analysis, Food Quality and Nutrition

Jiao LI, Liangang MAO, Yanning ZHANG, Lan ZHANG, Hongyun JIANG

Czech J. Food Sci., 2018, 36(3):227-232 | DOI: 10.17221/328/2017-CJFS

Changes in mango fruit quality, malondialdehyde content, and enzymatic activities in response to pathogen Alternaria alternata infection were studied. A. alternata significantly affected the appearance of mango fruit at 5 and 7 days after treatment (DAT). The quality of pathogen-infected fruit first showed a significant decrease in titratable acidity and vitamin C content and a significant increase in pH since 3 DAT. The malondialdehyde content was higher than that in the untreated controls at 3 and 7 DAT. The enzyme activities of ascorbate peroxidase and polyphenol oxidase showed significant increases since 3 DAT. Significant increases in l-phenylalanine ammonia-lyase and superoxide dismutase activities were observed at 7 DAT. These results indicate that A. alternata infection first significantly affects some biochemical constituents and enzyme activities in mango fruit since 3 DAT and that there was no significant effect on appearance until 5 DAT.

The effect of freezing storage on physical and chemical properties of wild boar meatFood Technology and Economy, Engineering and Physical Properties

Marian GIL, Paulina DUMA-KOCAN, Renata STANISŁAWCZYK, Mariusz RUDY

Czech J. Food Sci., 2018, 36(6):487-493 | DOI: 10.17221/62/2018-CJFS

The colour, chemical composition, texture parameters, hydration properties and fatty acids profile of fresh wild boar meat and meat after 2 months of freezing were compared. The research material was the M. longissimus dorsi muscle cut out of wild boar carcasses (Sus crofa). Analyses of physical and chemical properties of samples taken from 16 boars were performed. Samples were packed and frozen to -18°C and stored under such conditions for a period of two months. Freezing storage significantly increased the elasticity value and the colour of the meat as indicated by the decrease in L* and b* values. In frozen meat there slightly increased thermal drip and forced drip. The changes in the fatty acid profile under the effect of freezing were found more often in fat from muscle M. longissimus dorsi than in back fat of wild boar. In conclusion, it should be noted that freezing storage in a short time does not affect negatively the quality of frozen meat.

Antilisterial activity of lactic acid bacteria against Listeria monocytogenes strains originating from different sourcesOriginal Paper

Ivana SLOŽILOVÁ, Sabina PURKRTOVÁ, Michaela Kosová, Miroslava Mihulová, Eva ŠVIRÁKOVÁ, Kateřina DEMNEROVÁ

Czech J. Food Sci., 2014, 32(2):145-151 | DOI: 10.17221/475/2012-CJFS

Eight individual bacteriocin-producing lactic acid bacteria (LAB) strains and three bacteriocin-non-producing cheese starter cultures were evaluated for their ability to inhibit the growth of six Listeria monocytogenes strains, originating from the guinea-pig lymph nodes, raw cow milk, and manufacturing dairy equipment. Results showed that either live cells or cell-free neutralised supernatant (CFNS) and/or heated CFNS of six individual LAB strains (Lcc. lactis subsp. lactis CCDM 416 and NIZO R5, Lbc. plantarum HV 11 and DC 1246, P. acidilactici HV 12, and Ent. mundtii CCM 1282) and one starter culture (DELVO-ADD® 100-X DSF) were effective in the suppression of at least one listeria strain. Neither any individual LAB strain nor starter culture was antagonistic toward all studied L. monocytogenes strains, indicating diverse sensitivity/resistance among L. monocytogenes strains to antimicrobial compounds of LAB. The significant susceptibility of listerias isolated from raw milk and dairy equipment together with the strong antilisterial activity of DELVO-ADD® 100-X DSF could be applied in dairy technology, where commonly used starter cultures could play both the biopreservative and fermentation role.

Phenolic content and antioxidant capacity of Cypriot winesFood Analysis, Food Quality and Nutrition

Charis M. GALANAKIS, Anestis KOTANIDIS, Maria DIANELLOU, Vassilis GEKAS

Czech J. Food Sci., 2015, 33(2):126-136 | DOI: 10.17221/335/2014-CJFS

We characterised 12 wines (10 red, 1 sweet red, and 1 white) from different Cypriot cultivars in terms of their phenolic, anthocyanin composition, and antioxidant capacity as determined by two activities: radical scavenging and ferric reducing ability. Two different phenolic fractions (tannin-free and 1-kDa permeate) were also isolated from Cypriot wines with an ultimate goal of investigating their role in the overall antioxidant capacity of wines. The results indicated that Maratheftiko and Lefkada cultivars had higher concentrations of o-diphenols, hydroxycinnamic acid derivatives, flavonols and anthocyanins compared to other Cypriot cultivars like Ofthalmo, Mavro, and Giannoudi. The higher concentrations of phenols did not always correspond to a higher antioxidant capacity, probably due to the antagonistic action observed between hydroxycinnamic acid derivatives, flavonols, and anthocyanins. The latest interactions restricted the release of flavonols' advanced antiradical activity in wines.

Details of the antioxidant mechanism of hydroxycinnamic acidsFood Chemistry and Safety

Ya-Jing SHANG, Bao-Yong LIU, Meng-Meng ZHAO

Czech J. Food Sci., 2015, 33(3):210-216 | DOI: 10.17221/611/2014-CJFS

Antioxidant activities and free radical-mediated DNA strand breakages of five hydroxycinnamic acids were examined. Kinetic analysis of a stable galvinoxy (GO*)-scavenging reaction of hydroxycinnamic acids demonstrated that the molecular structure and the reaction medium were two important factors affecting the antioxidant mechanism and activity. In methanol, the kinetic process of the compounds, which have electron-donating groups (-OH, -OCH3) in the ortho- or para-position of 4-OH, was primarily governed by the sequential proton loss electron transfer (SPLET mechanism). While, in ethyl acetate, the reaction mechanism is predominantly direct hydrogen atom transfer (HAT mechanism). But for the compounds having only one hydroxyl, both in ethyl acetate and methanol, the reaction mechanism is only HAT. At the same time, the compound bearing o-diphenoxyl is not the most active one in our tested environment.

Phenolic amides (avenanthramides) in oats - a reviewReview

Hüseyin BOZ

Czech J. Food Sci., 2015, 33(5):399-404 | DOI: 10.17221/696/2014-CJFS

Whole grain cereals such as oats are important sources of phenolic compounds. Oats contain phenolic amides, also named avenanthramides (AVAs), which have beneficial health properties because of their antioxidant, anti-inflammatory, and antiproliferative effects. The most common avenanthramides are esters of 5-hydroxyanthranilic acid with p-coumaric (AVA-A), ferulic (AVA-B), or caffeic (AVA-C) acids. The studies related to the stability of AVAs showed that AVA-B is sensitive to alkaline and neutral conditions and this sensitivity increases with higher temperatures. However, has been reported that AVA-A and AVA -C are more stable under the same conditions (alkaline and neutral conditions), and in addition that AVAs content of oats is increasing significantly with the germination process. AVAs help in preventing free radicals from damaging LDL cholesterol while AVAs-enriched extract of oats combined with vitamin C synergistically inhibited LDL oxidation in vitro. Both animal studies and human clinical trials confirmed that oats antioxidants have the potential of reducing cardiovascular risks by lowering serum cholesterol and inhibiting LDL oxidation and peroxidation. Therefore, the consumption of oats and products thereof is extremely important in reducing the risk of cardiovascular diseases.

Collection of food relevant microscopic fungi under the Czech national programme of protection of genetic resources of economically significant microorganisms - a short report

Alena Kubátová

Czech J. Food Sci., 2010, 28(1):79-82 | DOI: 10.17221/235/2009-CJFS

A unique project exists in the Czech Republic, namely the Czech National Programme of Protection of Genetic Resources of Economically Significant Microorganisms and Tiny Animals (NPPGR), which includes nineteen Czech collections of microorganisms (bacteria, fungi), viruses, and tiny animals. It is fully financed by the Ministry of Agriculture of the Czech Republic. Under this Programme, the Culture Collection of Fungi (CCF) in Prague maintains 293 fungal strains, 225 of which are food and feed relevant fungi (e.g. toxigenic Aspergillus flavus, Penicillium verrucosum, and Fusarium sporotrichioides). The main aims of the Programme are to provide adequate protection of the microbial genetic resources that are of importance to the agriculture and food industries, to provide strains (free of charge) for the research and educational purposes, and to support the cooperation between Czech and foreign institutions. A database of all microorganisms is accessible online.

Detection of PCR inhibition in food and feed with a synthetic plasmidFood Analysis, Food Quality and Nutrition

Tereza Sovová, Barbora Křížová, Lenka Drábková, Jaroslava Ovesná

Czech J. Food Sci., 2017, 35(2):160-164 | DOI: 10.17221/374/2016-CJFS

We present a successful use of the plasmid inhibition detection and DNA isolation protocol optimisation for four food/feed samples in qPCR analysis of the sequence coding for chloroplast tRNA-Leu: two meat meal samples and two samples made of cranberries (jam and dried fruit). The quantitative real-time polymerase chain reaction (qPCR) can be inhibited by various substances and the DNA content in the sample can be underestimated. It is necessary to identify the PCR inhibition and choose an optimal DNA isolation protocol to correctly evaluate the sample. In a previous study, we have developed an assay using plasmid DNA carrying a non-homologous random sequence identifying possible inhibitors in qPCR in food/feed samples. The plasmid assay allowed to effectively reveal the PCR inhibition in all of the different sample matrices and to choose an optimal DNA isolation protocol.

Efficiency of PCR-RFLP and species-specific PCR for the identification of meat origin in dry sausagesFood Analysis, Food Quality and Nutrition

Ivona Djurkin Kušec, Danijela Samac, Vladimir Margeta, Žarko Radišić, Dragutin Vincek, Goran Kušec

Czech J. Food Sci., 2017, 35(5):386-391 | DOI: 10.17221/243/2016-CJFS

The purpose of this investigation was the identification of chicken, beef and sheep meat in pork sausages using PCR-RFLP and PCR with pecies-specific primers. Six dry fermented pork sausages were produced by adding beef, sheep and chicken meat to each in the amount of 1 and 5%. DNA was extracted from five regions of each sausage and PCR-RFLP together with PCR using species-specific primers was performed. PCR-RFLP analysis was successful only for chicken meat, while species-specific PCR was effective for identification of chicken, eef and sheep meat in all ratios and from all regions of the sausages. The results of our study show that discovering adulteration using PCR-RFLP is suitable only for chicken meat in the investigated products, while for detection of beef and sheep meat use of species-specific oligonucleotides is more effective.

Assessment of sensory quality of calf chops with different fat cover using a specific sensory method by a trained panelFood Analysis, Food Quality and Nutrition

Iñaki Etaio, Pilar F. Gil, Mónica Ojeda, Luis Javier R. Barron, Francisco José Pérez Elortondo

Czech J. Food Sci., 2017, 35(5):392-400 | DOI: 10.17221/276/2016-CJFS

Carcass fat cover is used in many countries as a predictor of meat quality, although studies relating this parameter to sensor y quality of meat are scarce and are mainly based on acceptability or palatability evaluation. The samples of calf chops with three different degrees of carcass fat cover were analysed according to a specific method for sensor y quality assessment. A trained panel evaluated the samples and scored the sensor y quality related to odour, texture, flavour, and persistence. Samples with higher carcass fat cover presented significantly better scores for texture, flavour, and persistence, although not for odour. When calculating global sensor y quality by integrating the cited parameters, significant differences were found between the three fat cover groups. Texture, f lavour, and persistence were also correlated with fat cover and marbling degree. Specific sensor y characteristics (medium tenderness, slightly tough, rancid odour, cooked meat aroma, equal or higher than fat aroma, ver y low aroma intensity, dominance of fat aroma, obvious liver aroma and milky aroma) contributed to explaining the quality differences obser ved among the groups.

Influence of modified atmosphere packaging on freshness parameters of organic chicken meat - short communicationShort Communication

Fouad Ali Abdullah Abdullah, Hana Buchtová, Peter Turek

Czech J. Food Sci., 2017, 35(5):466-468 | DOI: 10.17221/32/2017-CJFS

The effect of modified atmosphere packaging (MAP1 80% O2/20% CO2 and MAP2 70% N2/30% CO2) on the selected parameters (ammonia, thiobarbituric acid reactive substances /TBARS/) and antioxidant capacity in chilled meat (2 ± 2°C) of organic chickens (breast and thigh) was evaluated. Control samples were packaged using a polyolefin film. The experiment was conducted on day 2 and repeated on day 7, 10, and 14 of storage. TBARS of samples in MAP1 were higher than in samples stored in MAP2. Ammonia in meat in MAP2 was constant during storage. In general, the DPPH inhibition percentage of meat in MAP1 was lower than that in meat in MAP2. Results of the present study indicated that MAP2 could be preferable for the packaging of organic chicken meat.

Properties of fish and beef restructured by MTG derived from Streptomyces mobaraensis grown in media based on enzymatic hydrolysates of sorghumFood Technology and Economy, Engineering and Physical Properties

Guadalupe Rodríguez Castillejos, José Ramírez de León, Guadalupe Bustos Vázquez, Octelina Castillo Ruíz

Czech J. Food Sci., 2017, 35(6):517-521 | DOI: 10.17221/422/2016-CJFS

The efficiency of microbial transglutaminase (MTG) obtained from Streptoverticillum ladakanaum fermentation of sorghum grain and DDGS hydrolysates (HMTG) in increasing the mechanical properties of restructured meat and fish products was evaluated in this study. Gels were obtained by adding HMTG or commercial MTG at 0.3 U/g, and controls lacked enzyme. All treatments were supplemented with 2.0% NaCl. The gels with enzyme showed a lower amount of expressible water, similar to those obtained with CMTG (6% for fish gels and 8% for beef gels). Texture values were also similar. The results showed the feasibility of employing MTG obtained from sorghum hydrolysates.

Determination of free amino acids in cheeses from the Czech market

Ivana Kabelová, Markéta Dvořáková, Hana Čížková, Pavel Dostálek, Karel Melzoch

Czech J. Food Sci., 2009, 27(3):143-150 | DOI: 10.17221/1415-CJFS

High performance liquid chromatography (HPLC) method with the pre-column derivatisation by AccQ*Tag agent and following determination of these derivates after their separation in reverse phase column followed by fluorescent detection was used for the determination of amino acids in cheeses. The contents of sixteen free amino acids in twenty five cheeses commercially available in the Czech Republic were measured. The total content of free amino acids in the studied cheeses varied in the range from 27 g/kg to 160 g/kg. Among individual amino acids, seven amino acids were more concentrated in all cheese samples and came from three distinctive taste groups: bitter tasting amino acids (leucine, lysine, and phenylalanine), bitter sweet amino acids (proline and valine), and salty-umami amino acids (glutamic acid and aspartic acid). The differences in the contents of the total and individual free amino acids were influenced by the kind of cheese and mainly by the duration and intensity of proteolysis.

Changes produced in extra-virgin olive oils from cv. Coratina during a prolonged storage treatmentOriginal Paper

Antonietta BAIANO, Carmela TERRACONE, Ilaria VIGGIANI, Matteo Alessandro DEL NOBILE

Czech J. Food Sci., 2014, 32(1):1-9 | DOI: 10.17221/79/2013-CJFS

Extra-virgin oil is obtained from olive fruits only by mechanical means. The quality of extra-virgin olive oils is affected mainly by hydrolytic and oxidative reactions. For this reason, the commercial shelf-life is usually no longer than 18 months. In order to investigate the effects of a prolonged storage, olives from cv. Coratina were crushed using a three phase system to produce extra virgin olive oil analysed for sensory and chemical-physical indices, phenolic profile, tocopherol content, and antioxidant activity during a 8-years storage. The oil lost its characteristics of extra-virgin after 6 years of storage, time at which the median of the defects was higher than 0 and free acidity exceeded the limit fixed for this category by the European Regulation whereas the stability against oxidation persisted for a longer period due to the high concentration of oleuropein derivatives. A strong positive linear correlation was observed between the phenolic content and antioxidant activity measured according to the ABTS+. to indicate a noticeable radical scavenging ability of phenolic compounds.

Concentrating n-3 fatty acids from crude and refined commercial salmon oilOriginal Paper

Mª Elsa Pando, Beatriz Bravo, Macarena Berrios, Andrea Galdames, Catalina Rojas, Nalda Romero, Conrado Camilo, Cristian Encina, Matías Rivera, Alicia Rodríguez, Santiago P. Aubourg

Czech J. Food Sci., 2014, 32(2):169-176 | DOI: 10.17221/532/2012-CJFS

The urea complexation was used to concentrate n-3 fatty acids (FA) from crude and refined commercial salmon oils. The experimental procedure included salmon oil saponification, free fatty acid (FFA) collection, formation of urea-FFA inclusion complexes, extraction of free n-3 FA and further analysis by gas-liquid chromatography of the corresponding FA methyl esters. Differences between crude and refined salmon oil could be observed. Crude oil provided higher typical odour, viscosity and suspension particle values, whereas crude salmon oil showed higher FFA and impurities content while p-anisidine and iodine values, moisture content and formation of conjugated dienes and trienes did not provide any significant differences between both oils; refined oil showed lower a* and b* scores when compared to its counterpart crude oil. Related to the n-3 PUFA concentration, a decrease in saturated fatty acids C 14:0, C 16:0, and C 18:0 and monounsaturated fatty acids C 18:1 9c, and C 18:1 11c, as well as a high yield of n-3 PUFA, EPA+DHA and total PUFA recovering could be observed starting from both crude and refined oils, which confirmed salmon oil to be a profitable source of such highly valuable constituents. Factors such as reaction temperature and ureaFFA ratio showed to be markedly significant to achieve higher value concentrations.

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