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Changes in the levels of selected organic acids and sugars in apple juice after cold storageFood Technology and Economy, Engineering and Physical PropertiesJán MEZEY, Ivana MEZEYOVÁCzech J. Food Sci., 2018, 36(2):175-180 | DOI: 10.17221/165/2017-CJFS Apples are a source of sugars, acids, and various biologically active compounds, such as phenolic compounds, which are responsible for most of the antioxidant activities of the fruit. The aim of this study was to evaluate how the cold storage of apple fruits affects the nutritional composition of selected organic acid and sugar content in juice in comparison to juice from fresh fruits. Statistical differences were confirmed between the content of citric acid, malic acid, total acid, pH, sucrose, fructose and glucose in juice from fresh fruits and from juice stored for 140 days. No statistical differences were observed between juice from fresh fruit and juice from fruits stored for 140 days in the content of acetic acid, tartaric acid, total sugar and sweetness index. |
Contents of some biologically active amines in a Czech blue-vein cheeseTomáš Komprda, Vlastimil Dohnal, Renata ZávodníkováCzech J. Food Sci., 2008, 26(6):428-440 | DOI: 10.17221/7/2008-CJFS Biogenic amines (histamine, tyramine, tryptamine, phenylethylamine, cadaverine) including biologically active polyamines (putrescine, spermidine and spermine) were determined by HPLC method after 7, 21, 35, and 49 days of ripening in the core (C) and edge (E) samples of a blue-veined cheese, popular in the Czech Republic under the trade mark Niva, produced in the three consecutive months (October, November, December) from pasteurised cow milk using Penicillium roqueforti spores; two vats were produced in each month. The cheese vat, including the production period, accounted for (P < 0.05) one third and two thirds of the explained variability of the sum of biogenic amines and the sum of polyamines, respectively. The ripening time was significant (P < 0.05) from this viewpoint only in the case of the sum of biogenic amines (nearly half of the explained variability). Putrescine and spermidine contents in cheese did not change (P > 0.05), spermine content even decreased (P < 0.05) with increasing time of ripening. Tyramine content (Y, mg/kg) in the core samples increased linearly with increasing time of ripening (X, days), Y = 6.3 + 11.69X, R2 = 0.26, P < 0.001, contrary to the edge part where tyramine content did not change (P > 0.05). At the end of ripening (49 days), tyramine was quantitatively the most abundant amine (the mean and median 380 mg/kg and 289 mg/kg, respectively), its content in different cheeses (vats) varying from 10 mg/kg to 875 mg/kg. Cadaverine concentration varied between 3 mg/kg and 491 mg/kg (the mean 114, median 56 mg/kg). The levels of other biogenic amines and polyamines (with the exception of putrescine in the edge part of one of the December vats: 117 mg/kg) were very low even at the end of ripening. Tyramine contents at the end of ripening in the core-samples were higher (P < 0.01) in comparison with those in the edge-samples, contrary to histamine, cadaverine, putrescine, and spermine contents. |
Development of a triplex real-time PCR for simultaneous detection of allergenic ingredients in processed foodFood Chemistry and SafetyWenju ZHANG, Yulei ZHAO, Qingjin XU, Qin CHENCzech J. Food Sci., 2018, 36(1):22-27 | DOI: 10.17221/28/2017-CJFS SYBR Green real-time or quantitative PCR (Q-PCR) is a suitable system in which to establish a multiplex method to detect allergenic ingredients in food. In this study, a triplex Q-PCR method was developed to detect trace amounts of peanut, soybean and sesame in processed food. Specific PCR primer sets were designed and the concentration of the primers used in the triplex PCR was optimised. The triplex method showed high specificity and sensitivity which were similar to those of the simplex method, and it was applied for the detection of allergenic ingredients in commercially available processed food. The results demonstrate that the developed triplex Q-PCR is a quick, reliable and efficient method for the detection of allergenic ingredients in processed food. |
Rapid evaluation of fresh chicken meat quality by electronic noseFood Technology and Economy, Engineering and Physical PropertiesEdita RAUDIENÉ, Darius GAILIUS, Rimanté VINAUSKIENÉ, Viktorija EISINAITÉ, Gintautas BALČINAS, Justina DOBILIENÉ, Laura TAMKUTÉCzech J. Food Sci., 2018, 36(5):420-426 | DOI: 10.17221/419/2017-CJFS A prototype of electronic nose (e-nose) with the gas sensor system for evaluation of fresh chicken meat freshness was developed. In this paper a rapid, simple and not expensive system for fresh chicken meat spoilage detection was investigated that provides objective and reliable results. Quality changes in fresh chicken meat during storage were monitored by the metal oxide sensor (MOS) system and compared with the results of traditional chemical measurements. Gas sensor selection was tested for evaluation of volatile fatty acids (VFA) mainly representing meat spoilage.The study demonstrated that a correlation coefficient (R2 = 0.89) between e-nose signals and traditional chemical method was high. These results prove that the developed e-nose prototype has a potential for assessing fresh chicken meat freshness and allows discriminating meat into fresh, unsafe and spoiled. |
Influence of modified atmosphere packaging on freshness parameters of organic chicken meat - short communicationShort CommunicationFouad Ali Abdullah Abdullah, Hana Buchtová, Peter TurekCzech 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. |
Alcohol and Health: Standards of Consumption, Benefits and Harm - a ReviewReviewIsabela Maria MONTEIRO VIEIRA, Brenda Lohanny PASSOS SANTOS, Denise SANTOS RUZENE, Tomáš BRÁNYIK, José António TEIXEIRA, João Batista DE ALMEIDA E SILVA, Daniel PEREIRA SILVACzech J. Food Sci., 2018, 36(6):427-440 | DOI: 10.17221/117/2018-CJFS In order to establish a clear limit between protective and harmful effects of alcohol consumption, it is necessary to define patterns of consumption. However, there is no universally recognized quantitative classification for patterns of consumption by alcohol doses. This is because the pattern of alcohol consumption does not only describe how much alcohol was consumed, but also takes into account a number of boundary conditions. This review deals with variabilities in the definitions of standard alcohol doses and patterns of alcohol consumption. These terms are being discussed with respect to the benefits and harms associated with alcohol consumption as well as the risks intrinsic to studies of such a complex phenomenon as the effect of alcoholic beverages on human health. |
Geographical origin of honey from eight sub-regions of Bosnia and HerzegovinaFood Analysis, Food Quality and NutritionVildana Alibabić, Melisa Oraščanin, Nada VahčićCzech 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. |
The influence of gamma-irradiation on the formation of free radicals and antioxidant status of oregano (Origanum vulgare L.)Jana Horváthová, Milan Suhaj, Martin Polovka, Vlasta Brezová, Peter ŠimkoCzech J. Food Sci., 2007, 25(3):131-143 | DOI: 10.17221/741-CJFS The influence of various gamma-radiation dose absorptions on oregano (Origanum vulgare L.) solid samples was monitored by means of electron paramagnetic resonance (EPR) spectroscopy. Further, the antioxidant activity of oregano methanol/water extracts was characterised using DPPH (1,1-diphenyl-2-picrylhydrazyl free radical); thiobarbituric acid reactive substances (TBARS); ferric reducing power (FRP); and total content of phenolic compounds (TPC) assays. EPR spectroscopy was used for the investigation of the influence of the absorbed dose on the character of the paramagnetic structures formed, as well as for their thermal stability and life-time characterisation. EPR spectrum of the reference (non-irradiated) sample represents a broad singlet line with unresolved hyperfine splitting, attributable to Mn(II) ions, upon which the additional sharp EPR signal (g = 2.0022, ΔBpp ≈ 1 mT) is superimposed, assigned to stable semiquinone radicals produced by the oxidation of polyphenolic compounds present in plants. The additional paramagnetic structures of different origin (mostly of cellulose and carbohydrate), possessing diverse thermal stability and life-time, were identified in the gamma-irradiated samples. Immediately after irradiation, a statistically significant increase was observed of the TBARS values and the total content of phenolic compounds in methanol/water oregano extract. The alterations of the antioxidant properties of oregano extracts with the time after the radiation treatment were also monitored. A substantial time-dependent decrease of antioxidant activity was observed, probably as a result of storage, with both irradiated and non-irradiated oregano samples, as obvious from the ferric reducing power test and the content of total phenolic substances. The influence of irradiation and subsequent storage of oregano samples on the DPPH radical-scavenging ability was only negligible. |
Convective and microwave drying of onion slices regarding texture attributesFood Technology and Economy, Engineering and Physical PropertiesÖzge SÜFER, Hande DEMIR, Seda SEZERCzech J. Food Sci., 2018, 36(2):187-193 | DOI: 10.17221/310/2017-CJFS The textural characteristics of onion slices (Allium cepa L.) of 3- and 7-mm thicknesses undergoing convective drying (50, 60, and 70°C) and microwave drying (68, 204, and 340 W real effective power levels) techniques with or without pre-treatment were evaluated. Pre-treatment consisted of dipping into brine solution (8% NaCl). Texture profile analysis at 25% compression was applied and hardness, chewiness, springiness and gumminess values of onions were recorded. As the temperature (convective) or real effective power level (microwave) increased, the hardness and chewiness levels of dried onion slices were enhanced. The values of these parameters were higher in response to microwave application compared to convective drying. Pre-treatment had an additive effect on hardness and chewiness in convectively dried samples. Maximum springiness was observed in response to convective drying. Dipping in brine solution generally caused no significant changes among slices of the same thickness (P < 0.05). With respect to gumminess, the results were quite similar to those for hardness and chewiness, i.e., markedly higher in microwave-dried onions. |
Antioxidant activity of wines and related matters studied by EPR spectroscopyPavel STOPKA, Jana KŘÍŽOVÁ, Naděžda VRCHOTOVÁ, Petra BÁBÍKOVÁ, Jan TŘÍSKA, Josef BALÍK, Marie KYSELÁKOVÁCzech J. Food Sci., 2008, 26(10):S49-S54 | DOI: 10.17221/248/2008-CJFS Antioxidant activity and free radicals were studied in various parts of Vitis vinifera plant in vivo and in wines using EPR spectroscopy. Antioxidative properties of polyphenolic substances play an important role for the evaluation of quality of natural products. Determination of antioxidant activity of experimental samples by EPR method was based on measuring the changes of EPR spectrum of stable nitroxide radicals as a result of their interaction with antioxidants. In the leaves of Vitis vinifera vine varieties for the production of red wines there was observed a higher decrease in free Tempol radicals as compared to the leaves of varieties used for the production of white wines. For all monitored wines there was established a clear decrease in free Tempol radicals to the average value of 75.5 ± 15.6% as compared to the original EPR spectrum. A higher antioxidant activity was observed in yeast sediments from the production of red wines than in those from white ones. |
ELISA for free S-equol in human urineLucie Sosvorová, Petra Lanková, Marie Bičíková, Elena A. Prokudina, Nawaf Al Maharik, Oldřich LapčíkCzech J. Food Sci., 2011, 29(1):57-64 | DOI: 10.17221/130/2010-CJFS The popularity of phytoestrogen food supplements of plant origin steadily increases. They are used to solve the problems related to the climacterium. Their efficiency depends on woman's capability to metabolise the active components - isoflavonoids. Women able to convert daidzein to S-equol are supposed to get a greater benefit from these supplements. To determine S-equol urine levels, the competitive ELISA was developed. Carboxymethylequol coupled to BSA via 4'-O-position was used as an immunogen. The assay conditions, including the concentrations of the coating antigen and antisera, were optimised. The detection limit was 0.1 ng/ml (5 pg/well) and 50% intercept was 1 ng/ml (50 pg/well). The intraassay coefficients of variation (CV) varied from 4.7% to 9.9%, for the interassay CV the corresponding values of 2.6-11.6% were obtained. The recovery of the standard added to urine ranged between 89% and 104%. All examined samples were obtained from women in climacterium. The volunteers had been taking phytoestrogen food supplements for 3 months. The urine samples were collected before and after the therapy. The levels of free urinary S-equol after the therapy ranged between 0 ng/ml and 42.4 ng/ml. The equol production was observed in 57% of the examined patients. The laboratory results were confronted with patients' subjective evaluations. |
Phosvitin phosphopeptide preparation using immobilised trypsin and enhancing calcium absorption in growing ratsFood Analysis, Food Quality and NutritionQiang Zhong, Xing-Ling Li, Wei-Dong Hu, Bo Zeng, Ren-Ming Liang, Hui Liu, Zai-Xin Li, Zhi ZhangCzech 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. |
Preparation of conjugated linoleic acid enriched derivatives by conventional and biphasic isomerisationFood Chemistry and SafetyJan Kyselka, Lukáš Thomes, Simona Remišová, Miroslav Dragoun, Markéta Berčíková, Vladimír FilipCzech 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. |
Quality of eggs in different production systemsFood Technology and Economy, Engineering and Physical PropertiesGuler Yenice, Ozgur Kaynar, Mustafa Ileriturk, Feryaz Hira, Armagan HayirliCzech 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. |
Effect of slurry incorporation into retentate on proteolysis of Iranian ultrafiltered white cheeseFood Technology and Economy, Engineering and Physical PropertiesRahele Nezhad Razmjoui Akhgar, Javad Hesari, Sodeif Azadmard DamirchiCzech 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. |
Spent brewer's yeast extracts as a new component of functional foodFood Technology and Economy, Engineering and Physical PropertiesBartłomiej Podpora, Franciszek Świderski, Anna Sadowska, Rita Rakowska, Grażyna Wasiak-ZysCzech 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. |
Evidence for wheat, rye, and barley presence in gluten free foods by PCR method - comparison with ELISA methodEva Mašková, Ivana Paulíčková, Jana Rysová, Dana GabrovskáCzech J. Food Sci., 2011, 29(1):45-50 | DOI: 10.17221/171/2010-CJFS A method of the evidence for the presence of wheat, rye, and barley in gluten free foods, based on the polymerase chain reaction (PCR), was validated. DNA was isolated from foods by chaotropic solid phase extraction. The PCR method applied was focused on the intron of the chloroplast gene trnL and utilised primers WBR11 and WBR13. Electrophoresed wheat and rye DNAs were characterised by a 201 bp fragment, barley DNA by a 196 bp fragment. The validated PCR method was applied to the selection of 18 gluten free foods, previously found by ELISA method to contain 1 mg or more of gliadin per 100 g food. The presence of wheat was confirmed by PCR method in all foods analysed. The comparison with the results obtained by ELISA method reliably verified the detection limit of PCR method, i.e., 0.02% wheat. |
Effect of spelt pearling on the contents of total dietary fibre, wet gluten, protein and starch fractionsFood Technology and Economy, Engineering and Physical PropertiesRenata Winterová, Marie Holasová, Vlasta FiedlerováCzech J. Food Sci., 2016, 34(1):61-67 | DOI: 10.17221/453/2015-CJFS The important nutritional characteristics of the Rubiota spelt variety, grown in the Czech Republic, were reported. We evaluated the contents of total dietary fibre, protein, wet gluten, total starch, and starch fractions, i.e. rapidly digested starch, slowly digested starch, and resistant starch in pearled grain of spelt and in pearling fines. We measured these properties depending on the degree of kernel abrasion. Small differences were found between the sequential pearling cycles in the pearled spelt but significant differences were observed in the fines. In this study we also compared two methods for determining total and resistant starch. |
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 PropertiesGuadalupe Rodríguez Castillejos, José Ramírez de León, Guadalupe Bustos Vázquez, Octelina Castillo RuízCzech 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. |
Fermented buttermilk-based beverage: impact on young volunteers' health parametersFood Analysis, Food Quality and NutritionRaimondas Narkevičius, Arvydas Kaminskas, Jonas Algis Abaravičius, Dalius Vitkus, Valerija Jablonskienė, Dalia SekmokienėCzech J. Food Sci., 2016, 34(2):143-148 | DOI: 10.17221/344/2015-CJFS The technology of a functional fermented buttermilk-based beverage was developed and the impact of beverage consumption on the health parameters of young volunteers was studied. Three functional beverages were made on the basis of buttermilk, which differed in the composition. The beverage containing the buttermilk-skimmed milk-milk protein concentrate (0.3%) as a product with the preferred quality characteristics (synaeresis, viscosity, sensory properties, and acceptability) was used for further studies regarding the impact on human health. The medical nutrition experiments did not show any statistically significant effect on the biochemical blood parameters of 25 young volunteers after a 21-day period of the consumption of fermented buttermilk beverage with milk protein concentrate, although some of them (e.g. total, low- and high-density cholesterol, triacylglycerol concentrations, etc.) slightly decreased. The anthropometric and body composition, arterial blood pressure, and pulse evaluation indicators of recipients did not change significantly. |
Application of InDel markers based on the chloroplast genome sequences for authentication and traceability of tartary and common buckwheatFood Analysis, Food Quality and NutritionKwang-Soo Cho, Su-Young Hong, Bong-Kyoung Yun, Hong-Sik Won, Young-Ho Yoon, Ki-Beom Kwon, Manjulatha MekapoguCzech J. Food Sci., 2017, 35(2):122-130 | DOI: 10.17221/116/2016-CJFS A reliable, qualitative PCR-based detection method for the traceability and authentication of common and Tartary buckwheat was developed. Five InDel markers developed from chloroplast genome variation between the two species were applied for 96 buckwheat accessions and all accessions were easily differentiated as Tartary and common buckwheat using these markers. We also determined the sample detection limit by PCR and qPCR as 0.001 and 0.02 ng/µl, respectively. InDel markers could detect the mixture of two species flour up to 10% contamination. InDel markers were also applied to processed foods such as noodles and tea, and we found that species-specific PCR bands could be used to identify buckwheat even after processing. Hence, these InDel markers are simple with higher specificity and sensitivity and are reliable for the authentication of buckwheat processed foods. |
Quality of shiitake stipe steamed bunYu-Hsiu Tseng, Joan-Hwa Yang, Chi-En Lee, Jeng-Leun MauCzech 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. |
Simultaneous determination of the residues of fourteen quinolones and fluoroquinolones in fish samples using liquid chromatography with photometric and fluorescence detectionFlorentina Cañada-Cañada, Anunciacion Espinosa-Mansilla, Ana Jiménez Girón, Arsenio Muñoz de la PeñaCzech J. Food Sci., 2012, 30(1):74-82 | DOI: 10.17221/12/2010-CJFS A chromatographic method is described for assaying fourteen quinolones and fluoroquinolones (pipemidic acid, marbofloxacin, norfloxacin, ciprofloxacin, danofloxacin, lomefloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, nalidixic acid, flumequine, and pyromidic acid) in fish samples. The samples were extracted with m-phosphoric acid/acetonitrile mixture (75:25, v/v), purified, and preconcentrated on ENV + Isolute cartridges. The determination was achieved by liquid chromatography using C18 analytical column. A mobile phase composed of mixtures of methanol-acetonitrile-10mM citrate buffer at pH 4.5, delivered under optimum gradient program, at a flow rate of 1.5 ml/min, allows accomplishing the chromatographic separation in 26 minutes. For the detection were used serial UV-visible diode-array at 280 nm and 254 nm and fluorescence detection at excitation wavelength/emission wavelength: 280/450, 280/495, and 280/405 nm. The detection and quantification limits were between 0.2-9.5and 0.7-32 µg/kg, respectively. The procedure was applied to the analysis of spiked salmon samples at two different concentration levels (50 µg/k and 100 µg/kg). Mean recoveries of fluoroquinolones from the salmon samples ranged from 50% to 102%, depending on the analyte. |
Assessment of sensory quality of calf chops with different fat cover using a specific sensory method by a trained panelFood Analysis, Food Quality and NutritionIñaki Etaio, Pilar F. Gil, Mónica Ojeda, Luis Javier R. Barron, Francisco José Pérez ElortondoCzech 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 chestnut flour addition on quality characteristics of pasta made on extruder and minipressFood Technology and Economy, Engineering and Physical PropertiesIndira Kosović, Marko Jukić, Antun Jozinović, Đurđica Ačkar, Daliborka Koceva KomlenićCzech J. Food Sci., 2016, 34(2):166-172 | DOI: 10.17221/451/2015-CJFS Durum semolina was replaced with 10, 15, and 20% of chestnut flour. Pasta was produced on a single screw extruder with the temperature profile of 80/90/90°C and on a laboratory minipress. Pasta samples were dried at room temperature and physical and sensory properties were determined. Generally, the chestnut flour addition to durum wheat pasta decreased optimum cooking time, hardness, cohesiveness, and chewiness, but increased cooking losses and pasta adhesiveness. Samples made on an extruder showed shorter optimum cooking times in relation to samples made on a minipress. Absorbed water was decreased with chestnut flour addition. Pasta made on an extruder showed a higher sensory score in comparison with pasta made on a minipress. The addition of chestnut flour influenced the colour of the samples. Samples made on an extruder showed darker colour in dried and cooked pasta samples in relation to minipress samples. In dried pasta samples, the extruder gave yellower samples in relation to the minipress, while in cooked pasta samples it was reversed. Overall, the extruder gave higher-quality pasta compared to the minipress. |
Phytochemical changes in mango fruit in response to Alternaria alternata infectionFood Analysis, Food Quality and NutritionJiao LI, Liangang MAO, Yanning ZHANG, Lan ZHANG, Hongyun JIANGCzech 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. |
Effect of chokeberry juice consumption on antioxidant capacity, lipids profile and endothelial function in healthy people: a pilot studyFood Analysis, Food Quality and NutritionDariusz Nowak, Zofia Grąbczewska, Michał Gośliński, Karolina Obońska, Anita Dąbrowska, Jacek KubicaCzech J. Food Sci., 2016, 34(1):39-46 | DOI: 10.17221/258/2015-CJFS Many studies show that the consumption of juices rich in polyphenols may increase serum antioxidant capacity, improve blood lipid profile, and endothelial function. The relation between the consumption of chokeberry juice and changes in the antioxidant capacity, blood lipid profile, and endothelial function as important indicators in the assessment of cardiovascular risk were determined. The study was conducted on a group of 11 healthy volunteers, who consumed chokeberry juice for three weeks. The research included determination of serum antioxidant capacity, blood lipid profile analysis, and measurements of endothelial function. The 3-week consumption of chokeberry juice significantly increased serum antioxidant capacity, and the best results were observed just after one week of the experiment. However, there was no significant change in the blood lipid profile, except for the persons with a higher level of triglycerides, in whom the consumption of chokeberry juice reduced these compounds to normal values. The endothelial function was normal in all patients and did not significantly change during the study. |
Modelling the rheological behaviour of enzyme clarified lime (Citrus aurantifolia L.) juice concentrateShringari Subramanyaiah MANJUNATHA, Pakalapati Srinivasa RAJU, Amrindar Singh BAWACzech J. Food Sci., 2012, 30(5):456-466 | DOI: 10.17221/257/2011-CJFS The rheological behaviour of enzyme clarified Lime (Citrus aurontifolia L.) juice was studied as a function of the total soluble solid (TSS) content (7.3-55.7°Brix), corresponding water activity (aw) (0.985-0.831) at different temperatures (20-80oC) using co-axial controlled stress rheometer. The rheological parameter shear stress was measured up to the shear rate of 600 s-1. The investigation showed that the enzyme clarified lime juice and its concentrate behaved like a Newtonian fluid with the viscosity (η) being in the range 3.964 to 50.290 mPa s depending upon the concentration and temperature used. The temperature dependency on the viscosity of lime juice was described by Arrhenius equation (r > 0.99) and the activation energy (Ea) of viscous flow was in the range 4.151 to 26.050 kJ/mol depending upon the total soluble solids content. The effect of total soluble solid content on the flow activation energy was described by exponential type equation (r > 0.98) and that of water activity was described by both the power law and exponential equations (r > 0.99). The effect of total soluble solid content on the viscosity of lime juice followed the second order exponential equation (r > 0.99) at the temperature used. The effect of water activity on the viscosity was described by both the power law and exponential type relationship (r > 0.97). The equations relating to the combined effect of temperature and total soluble solids content/water activity on the viscosity of enzyme clarified lime juice were established. |
Biochemical changes of Iranian probiotic Lighvan cheeseFood Technology and Economy, Engineering and Physical PropertiesAlireza SHAHAB LAVASANICzech 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. |
Ultrasonic microwave-assisted extraction of polyphenols, flavonoids, triterpenoids, and vitamin C from Clinacanthus nutansFood Technology and Economy, Engineering and Physical PropertiesQun Yu, Chuan Li, Zhenhua Duan, 2*, Bing Liu, Weiwen Duan, Feifei ShangCzech J. Food Sci., 2017, 35(1):89-94 | DOI: 10.17221/82/2016-CJFS Polyphenols, flavonoids, triterpenoids, and vitamin C from Clinacanthus nutans were extracted by an ultrasonic microwave-assisted method. The optimal extraction conditions were established in distilled water, solid-liquid ratio 1 : 55 g/ml, irradiation power 90 W, and extraction cycle with 75 seconds. Results revealed that the solid-liquid ratio exerted a significant effect on polyphenols, whereas the irradiation power played a key role in the extraction of flavonoids, triterpenoids, and vitamin C. Under these conditions the extraction yield of each component was: polyphenols 8.893, flavonoids 25 936, triterpenoids 16 789, and vitamin C 0.166 mg/g. These results showed that the ultrasonic microwave-assisted extraction was an efficient technology to extract bioactive substances from Clinacanthus nutans and Clinacanthus nutans could potentially be a source of natural antioxidants. |
