Czech Journal of Food Sciences, 2013 (vol. 31), issue 5

Effect of freezing rate and comminution on dielectric properties of porkOriginal Paper

James G. LYNG, Lu ZHANG, Francesco MARRA, Nigel P. BRUNTON

Czech J. Food Sci., 2013, 31(5):413-418 | DOI: 10.17221/350/2012-CJFS  

The impact of comminution and the freezing rate on the dielectric properties (ε' and ε'') of meats measured at frequencies used for cooking, i.e. radio frequency, RF (27.12 MHz), and microwave, MW (915 and 2450 MHz), were evaluated. The temperature rises (ΔT) were also measured following standardised RF or MW cooking protocols (90 s at 450 W). A factorially designed experiment was conducted and the results suggested that ε' and ε'' were generally, though not always, significantly lower in more highly comminuted samples. At MW frequencies in meats with added ingredients, the frozen products generally had...

Influence of various pork fat types on the ripening and characteristics of dry fermented sausageOriginal Paper

Josef KAMENÍK, Pavla STEINHAUSEROVÁ, Alena SALÁKOVÁ, Zdeněk PAVLÍK, Gabriela BOŘILOVÁ, Ladislav STEINHAUSER, Jiří RUPRICH

Czech J. Food Sci., 2013, 31(5):419-431 | DOI: 10.17221/227/2012-CJFS  

The influence of three types of pork adipose tissue (neck, back, and leg) on the quality of dry fermented sausages was evaluated. No statistically significant differences between the most abundantly represented methyl esters of fatty acids (FA), such as C16:0, C18:0 and C18:1n-9, were found when the individual FA compositions of the pork adipose tissue samples were compared. The content of polyunsaturated FA was the highest in the neck adipose tissue and the lowest in the leg adipose tissue. These differences were not, however, statistically significant. No differences between the adipose tissue types were found in the sensory, colour, and...

Changes in conjugated linoleic acid content in Emmental-type cheese during manufacturingOriginal Paper

Jacek DOMAGAŁA, Agnieszka PLUTA-KUBICA, Henryk PUSTKOWIAK

Czech J. Food Sci., 2013, 31(5):432-437 | DOI: 10.17221/397/2012-CJFS  

The fatty acids composition including the conjugated linoleic acid content in the milk and in the samples of Emmental-type cheese during the manufacturing and ripening period was determined. The highest amount of volatile and the lowest amount of saturated fatty acids were observed at the end of ripening. In turn, the highest content of monounsaturated fatty acids was found in the curd, however, it declined during processing. The richest in polyunsaturated fatty acids were the cheese samples after the warm room stage, however, the amount of these fatty acids became highly significantly lower at the end of ripening. The level of conjugated linoleic...

Composition and sensory analysis for quality evaluation of a typical Italian cheese: influence of ripening periodOriginal Paper

Patrizia PAPETTI, Angela CARELLI

Czech J. Food Sci., 2013, 31(5):438-444 | DOI: 10.17221/447/2012-CJFS  

Caciottina massaggiata di Amaseno, a typical dairy product of the Lazio Region prepared from buffalo milk, was analysed for moisture, fat, protein, pH, and acidity content at different storage (0, 3, 6, and 9 months after production). Cheeses were also evaluated for various sensory attributes (taste, flavour, texture, and overall acceptability) during storage. We evaluated the flavour profile and acceptability of Caciottina cheeses of varying maturity using a descriptive analysis. Descriptive sensory profiles of selected cheeses were determined using a trained panel (n = 12) and an established cheese flavour sensory language. In quantitative...

Fat quality of marketable fresh water fish species in the Republic of SerbiaOriginal Paper

Dragana Ljubojević, Miroslav Ćirković, Vesna Đorđević, Nikola Puvača, Dejana Trbović, Jovan Vukadinov, Nada Plavša

Czech J. Food Sci., 2013, 31(5):445-450 | DOI: 10.17221/53/2013-CJFS  

The chemical and fatty acid composition were evaluated of commercially important fish species (common carp, silver carp, bighead carp, grass carp, Wels catfish, and zander) which were collected from retail stores in the area of Novi Sad, Republic of Serbia. The amount of protein was the highest in zander (19.27%) and the lowest in grass carp fillets (14.73%). The percentage of fat ranged from 1.8 in zander to 10.07 in common carp. The total cholesterol content was the highest in Chinese carps fillets (approximately 65.38 mg/100 g), and the lowest in Wels catfish (33.14 mg/100 g). SFA were lowest in zander (28.6%). Bighead carp meat contained the highest...

Effects of chitosan coating containing antioxidant of bamboo leaves on qualitative properties and shelf life of silver carp during chilled storageOriginal Paper

Fan Wenjiao, Zhang Yongkui, Diao Pan, Yi Yuwen

Czech J. Food Sci., 2013, 31(5):451-456 | DOI: 10.17221/149/2013-CJFS  

The effect of chitosan coating containing antioxidant of bamboo leaves (AOB) on the shelf life extension of silver carp (Hypophthalmicthys molitrix) was evaluated at refrigerated temperature (4 ± 1°C). Microbiological changes (total viable count - TVC), physicochemical changes (water loss, pH, total volatile nitrogen - TVB-N, trimethylamine - TMA-N, and 2-thiobarbituric acid - TBA), and sensory changes were determined during chilled storage. The results indicated that the coating treatments could effectively retard the water loss, inhibit the growth of total viable counts, reduce chemical spoilage, which reflected itself in TVB-N, pH,...

Improving the quality of whole wheat bread by using various plant origin materialsOriginal Paper

Hüseyin Boz, Mehmet Murat Karaoglu

Czech J. Food Sci., 2013, 31(5):457-466 | DOI: 10.17221/410/2012-CJFS  

The effects of various plant origin materials such as defatted Cephalaria syriaca flour (0.5%), rosehip (2.5%), vital gluten (2.5%), and malt flour (2%), and their combination on the quality of whole wheat bread were investigated. The plant origin materials used showed significant effects on the specific volume, acidity, colour, and textural properties of whole wheat bread. In general the acidity, specific volume, cohesiveness, and springiness values of whole wheat bread produced by treatments with plant origin materials were higher than those of the control bread. Treatment 13 (2% malt flour + 0.5% defatted Cephalaria syriaca flour...

Effect of postharvest storage temperatures on the quality parameters of pistachio nutsOriginal Paper

Elena ARENA, Gabriele BALLISTRERI, Biagio FALLICO

Czech J. Food Sci., 2013, 31(5):467-473 | DOI: 10.17221/69/2013-CJFS  

Pistachios from Italy and Turkey were stored at different temperatures (10, 20, and 30°C) and the moisture of the pistachios, the free fatty acids (FFA) content, the peroxide value, and triacylglycerols (TGs) composition of the extracted oils were evaluated. The content of FFA decreased during storage at 10°C and increased at 20 and 30°C. No differences between the peroxide values were found during storage at 10°C. A significant increase in the peroxide values was observed after 20 days at 20°C and 5 days at 30°C in both the Italian and Turkish samples. The main TGs found in the pistachio oil of both origins were OLO, OLL, OLP, LLL, LLP, OOP, OLLn,...

Authentication of Riesling wines from the Czech Republic on the basis of the non-flavonoid phenolic compoundsOriginal Paper

Pavel Pavloušek, Michal Kumšta

Czech J. Food Sci., 2013, 31(5):474-482 | DOI: 10.17221/40/2013-CJFS  

Eighteen non-flavonoid phenolic compounds comprising hydroxybenzoic acids, hydroxycinnamates, and stilbenes were analysed in 43 monovarietal wines originated from five wine-growing regions in the Czech Republic. The non-flavonoid phenolic compounds in wine were analysed by a HPLC method. The methods of multivariate statistical analysis were used for the wine discrimination on the basis of the geographical origin. The canonical discriminant analysis (CDA) proved the possibility to discriminate wines according to their provenance on the basis of the following parameters: protocatechuic acid, p-hydroxybenzoic acid, caftaric acid, p-coutaric...

Distribution patterns of polyphenols and alkaloids in instant coffee, soft and energy drinks, and teaOriginal Paper

Noelia MANCHÓN, Laura MATEO-VIVARACHO, Matilde D'ARRIGO, Ana GARCÍA-LAFUENTE, Eva GUILLAMÓN, Ana VILLARES, Mauricio Ariel ROSTAGNO

Czech J. Food Sci., 2013, 31(5):483-500 | DOI: 10.17221/443/2012-CJFS  

A previously developed method of HPLC-DAD-Fl has been used for the determination of phytochemical profiles in different types of drinks: instant coffee, soft drinks, energy drinks, and different types of tea (green, white, black, and red tea). Using data on the concentrations of 20 main phytochemicals (phenolic acids, flavan-3-ols, flavonols, flavones, and alkaloids) it was possible to identify most of the sample types. Chlorogenic and caffeic acids, and caffeine are the main target compounds in instant coffee; in soft and energy drinks, only caffeine was found. Tea has a more complex phytochemical composition. Unfermented tea is mainly composed of...

Comparison of phenolic content and antioxidant capacity of red and yellow onions.Original Paper

Anwei Cheng, Xiangyan Chen, Qiong Jin, Wenliang Wang, John Shi, Yaobo Liu

Czech J. Food Sci., 2013, 31(5):501-508 | DOI: 10.17221/566/2012-CJFS  

The total polyphenol (TP), flavonoid, proanthocyanidin (PAC) content, and antioxidant capacity of both onion varieties (red and yellow) were compared. The content of TP, flavonoids, and PAC was determined by Folin-Ciocalteu colorimetric method, AlCl₃, and by DMAC colorimetric method, respectively. The results showed that the contents of TP and flavonoids decreased from the outer to the inner layers in both onions, but there was no significant difference in PAC content. The outer layers had the highest antioxidant activity of extracts followed by a continuous decrease towards the inner layers in both varieties. The contents of phenolic acids...

Effect of drying method on the phenolic content and antioxidant capacity of spearmintOriginal Paper

Antia Orphanides, Vlasios Goulas, Vassilis Gekas

Czech J. Food Sci., 2013, 31(5):509-513 | DOI: 10.17221/526/2012-CJFS  

The changes in total phenolics, hydroxycinammic acid derivatives, and antioxidant properties of spearmint after five drying treatments (convection oven drying, freeze-drying, microwave drying, and air drying with the sun exposure and without the sun exposure) were investigated. Phenolic composition of dried spearmint was analysed by spectrophotometric assays, while DPPH radical scavenging activity and Ferric reducing/Antioxidant power (FRAP) assay was used to measure the antioxidant properties. The results showed that freeze drying produced dried spearmint that had the highest total phenolics (34.6 ± 1.9 mg/g) content and the most potent antioxidant...

Rapid immunoassays for detection of anabolic nortestosterone in dietary supplementsOriginal Paper

Barbora HOLUBOVÁ, Sandra GÖSELOVÁ, Ludmila ŠEVČÍKOVÁ, Miroslav VLACH, Martina BLAŽKOVÁ, Oldřich LAPČÍK, Ladislav FUKAL

Czech J. Food Sci., 2013, 31(5):514-519 | DOI: 10.17221/507/2012-CJFS  

An enzyme immunoassay (ELISA) and an immunochromatographic strip were designed for a rapid detection of nortestosterone in dietary supplements. Two polyclonal antibodies and two types of nortestosterone-protein coating conjugates were tested to develop the most appropriate method. Under optimal experimental conditions, the most sensitive ELISA achieved the IC₅₀ and the limit of detection values of 6.41 and 0.09 ng/ml, respectively. The assay specificity was tested measuring cross-reactivity of several steroids. The interference with the assay was negligible (< 0.1%), except for cross-reactivity with another frequently abused steroid testosterone...

Analysis of ochratoxin A in malt beverage samples using dispersive liquid-liquid microextraction coupled with liquid chromatography-fluorescence detectionOriginal Paper

Mehdi MAHAM, Vahid KIAROSTAMI, Syed WAQIF-HUSAIN, Rouhollah KARAMI-OSBOO, Mansoureh MIRABOLFATHY

Czech J. Food Sci., 2013, 31(5):520-525 | DOI: 10.17221/543/2012-CJFS  

A simple and economic procedure based on dispersive liquid-liquid microextraction has been applied to extract and pre-concentrate trace levels of ochratoxin A (OTA) in malt beverage prior to analysis using high performance liquid chromatography with fluorescence detection. The method was based on the formation of fine droplets of a water-immiscible extraction solvent in the sample solution using a water-miscible disperser solvent. The influences of various parameters such as the type and volume of extraction and disperser solvents, centrifuging time, sonication time, and salt concentration on the extraction efficiency of ochratoxin A were investigated....