Czech Journal of Food Sciences, 2014 (vol. 32), issue 5

Different peach cultivars and their suitability for minimal processingOriginal Paper

Maria Del Carmen Fuentes-Pérez, Sergio Nogales-Delgado, Maria Concepción Ayuso, Diego Bohoyo-Gil

Czech J. Food Sci., 2014, 32(5):413-421 | DOI: 10.17221/320/2013-CJFS  

Consumption of minimally processed fruits has been increased lately mainly due to their fresh-like quality characteristics. One of the major alterations that limit the shelf-life of these products is browning caused by polyphenol oxidase (PPO) activity on phenolic compounds. Six yellow-flesh peach cultivars, Spring Lady, Royal Glory, Ruby Rich, Summer Rich, Ryan Sun, and O'Henry, were selected. Peaches were hygienised and then samples were processed in a clean room. Slices were washed in cold tap water, dried, packaged in modified atmosphere, and stored at 4°C during 9 days; physicochemical and other quality parameters were studied. Principal Component...

Influence of cultivation conditions on the growth of Lactobacillus acidophilus, Bifidobacterium sp., and Streptococcus thermophiles, and on the production of organic acids in fermented milksOriginal Paper

Jana CHRAMOSTOVÁ, Romana MOŠNOVÁ, Ivana LISOVÁ, Erik PEŠEK, Jan DRBOHLAV, Irena NĚMEČKOVÁ

Czech J. Food Sci., 2014, 32(5):422-429 | DOI: 10.17221/616/2013-CJFS  

The parameters influencing the formation of organic acids and the ratio between the optical isomers of lactic acid were evaluated. Five different factors were tested, namely the form of starter, inoculum, temperature of fermentation, time of fermentation, and enhanced non-fat dry matter or addition of whey protein concentrate. Out of them, optimal conditions were chosen for the preparation of fermented milk beverage with ABT culture (Lactobacillus acidophilus, Bifidobacterium sp., Streptococcus thermophilus) with a lowered content of d(-)-lactic acid. The inoculum of bifidobacteria had the only significant effect...

Purification and characterisation of the bacteriocin produced by Lactobacillus plantarum, isolated from Chinese pickleOriginal Paper

Fang Zhou, Hongfei Zhao, Fengling Bai, Piotr Dziugan, Yuen Liu, Bolin Zhang

Czech J. Food Sci., 2014, 32(5):430-436 | DOI: 10.17221/270/2013-CJFS  

119 strains of lactic acid bacteria from Chinese pickle were tested for production of antimicrobial compounds (bacteriocins). Among them, strain C8 showed strongly antibacterial activity against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 8739. Strain C8 was identified as Lactobacillus plantarum based on phenotypical, physiological tests and 16S rDNA identification. The antibacterial substance produced by strain C8 was sensitive to protease but not affected by lipase and amylase and designated as bacteriocin C8. Bacteriocin was purified by salting-out, dialysis and Sephadex G50 column chromatography. Based on...

Proteomic analysis of wheat α/A- and β-gliadinsOriginal Paper

Marta DZIUBA, Dorota NAŁĘCZ, Iwona SZERSZUNOWICZ, Jacek WAGA

Czech J. Food Sci., 2014, 32(5):437-442 | DOI: 10.17221/600/2013-CJFS  

Gliadins from the Polish common winter wheat cultivar Sukces were analysed by analytical and preparative A-PAGE combined with 2-DE method. The main aim of this study was to identify the highest possible number of a/A- and β-gliadin fractions. Gliadins from the wheat cv. Sukces were separated by 2-DE into 82 spots. Preparative A-PAGE combined with the 2-DE method supported the identification of the analysed gliadin fractions. 12 spots were identified as typical a/A-gliadins out of 40 and 7 as typical β-gliadins out of 15 separated by 2-DE.

Furan and alkylated furans in heat processed food, including home cooked productsOriginal Paper

Arvid Fromberg, María S. Mariotti, Franco Pedreschi, Sisse Fagt, Kit Granby

Czech J. Food Sci., 2014, 32(5):443-448 | DOI: 10.17221/341/2013-CJFS  

The occurrence of furan in home cooked food was studied. Cooking was found to reduce the level of furan in ready-to-eat foods, however on average around 50% of furan remain in the foods. The analysis of furan occurrence revealed that it is most commonly formed in foods with high levels of carbohydrates. Interestingly, breakfast cereals, dry bread products, and dried fruit products including raisins, plums and bananas contained furan at levels up to 387 µg/kg. Furan was also found in the dry ingredients of cookies and bread, and in snacks such as crisps and popcorn. The 2-alkylfurans, 2-methylfuran, 2,5-dimethylfuran, 2-ethylfuran, and 2-pentylfuran...

A novel sorbent for solid-phase extraction coupling to high performance liquid chromatography for the determination of olaquindox in fish feedOriginal Paper

Dongyan ZHAO, Qiu Yi SHI, Xiong HE, Jing ZHANG

Czech J. Food Sci., 2014, 32(5):449-455 | DOI: 10.17221/16/2014-CJFS  

A new and hydrophilic molecularly imprinted polymer (MIP) selective for olaquindox was prepared by bulk polymerisation using methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the crosslinker. The synthesised polymer was characterised by Fourier-transform infrared and static adsorption experiments. Results showed that the MIP had good recognition and selective ability for olaquindox. A novel method based on molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography was developed for the separation and determination of trace olaquindox in feed samples. Under selected experimental conditions,...

Inspection of quince slice dehydration stages based on extractable image featuresOriginal Paper

Abdolabbas JAFARI, Adel BAKHSHIPOUR

Czech J. Food Sci., 2014, 32(5):456-463 | DOI: 10.17221/461/2013-CJFS  

The relation between the moisture content of the fruit and image-based characteristics was investigated. Quince samples were dried in an oven dryer at three different temperatures (40, 50, and 60°C). Several shape, texture, and colour features of the quince slices were extracted from the images. Gradual reduction was observed in all morphological features when the moisture content of the samples decreased. Regression equations between the extracted features and moisture content of the quince slices were investigated. The moisture content prediction equations based on morphological features were more precise than the textural features while colour information...

Yield stress and sensorial evaluation of soya yoghurts prepared from germinated soybeansOriginal Paper

Aleš LANDFELD, Pavla NOVOTNÁ, Jan STROHALM, Jana RYSOVÁ, Milan HOUŠKA

Czech J. Food Sci., 2014, 32(5):464-469 | DOI: 10.17221/534/2013-CJFS  

We used the germinated soybeans to prepare and evaluate soya yoghurts, with substantially reduced α-galactosides (AG) contents. The lower AG content allows the production of final products that do not cause flatulence. To enable us to control the final consistency and other sensory parameters of soya yoghurts, it was necessary to study the influence of the dry matter content on these quality parameters, i.e. the yield stress, appearance, flavour, taste, soya off-flavour, consistency, and overall impression. Establishing the relationships between the dry matter content and qualitative parameters allowed for an easy prediction of the optimal amount...

Effect of cluster and berry thinning on Merlot and Cabernet Sauvignon wines compositionOriginal Paper

Marko KAROGLAN, Mirela OSREČAK, Luna MASLOV, Bernard KOZINA

Czech J. Food Sci., 2014, 32(5):470-476 | DOI: 10.17221/598/2013-CJFS  

The manipulation of grape yield is widely practised to improve grape and wine quality. Merlot and Cabernet Sauvignon vines in the Zagreb vineyard hills, north-western Croatia, were subjected to three crop removal treatments [cluster thinning (CT), berry thinning (BT), CT+BT, and untreated control] in a randomised block design experiment. CT and CT+BT treatments reduced the grape yield but increased the mean cluster weight compared to control vines. BT alone had a little effect on the yield components. Control grapes generally had the lowest soluble solids (°Oe) and highest titratable acidity (g/l). In most cases, control wines had the lowest total...

Optimisation of the antioxidant activity of kombucha fermented milk productsOriginal Paper

Radomir MALBAŠA, Jasmina VITAS, Eva LONČAR, Jovana GRAHOVAC, Spasenija MILANOVIĆ

Czech J. Food Sci., 2014, 32(5):477-484 | DOI: 10.17221/447/2013-CJFS  

The antioxidant activity of fermented milk products obtained by using kombucha starter produced by fermentation on sweetened wild thyme extract was investigated. The starter was added to milk containing 0.8, 1.6, and 2.8% milk fat, at fermentation temperature of 37, 40, and 43°C. The fermentation process was terminated when the pH reached 4.5. Antioxidant activities to DPPH and hydroxyl radicals, the contents of MUFAs, PUFAs, vitamin C, and sensory mark, were monitored using the response surface methodology (RSM) and the method of desired function. Kombucha fermented milk products containing wild thyme (WT) showed opposite antioxidant response to DPPH...

The impact of moist corn grain preservation on the ethanol yield by simultaneous saccharification and fermentation, and on volatile by-productsOriginal Paper

Jacek NOWAK, Katarzyna SZAMBELAN, Włodzimierz NOWAK

Czech J. Food Sci., 2014, 32(5):485-492 | DOI: 10.17221/415/2013-CJFS  

We assessed the composition of volatile by-products in raw spirits obtained from moist corn fermentation. The average moisture value of the researched samples was 35.4%. A comparative research was conducted applying simultaneous saccharification and fermentation (SSF) process with Saccharomyces cerevisiae. The analysis characterised corn grains after three and six months of storage in aerobic and anaerobic conditions. The yield of ethanol fermentation was 42.43 and 39.12 l/100 kg dry matter after three and six months of storage, respectively. The storage of moist grain resulted in the reduction of higher alcohols content in the raw spirits....

Effects of frying fat and preparation on carp (Cyprinus carpio) fillet lipid composition and oxidationOriginal Paper

Sabine SAMPELS, Tomáš ZAJÍC, Jan MRÁZ

Czech J. Food Sci., 2014, 32(5):493-502 | DOI: 10.17221/405/2013-CJFS  

We investigated the changes in omega 3 enriched carp fillets caused by pan frying. The investigated characteristics were fat uptake, fatty acid (FA) composition, and oxidation. Four different fats were used and fillets were fried plain or battered. The fillet fat content increased during frying and FA composition in the fillets reflected the composition of the frying fat. Frying with sunflower oil negatively influenced the nutritional value by decreasing the n-3/n-6 ratio in the fillets. Frying with rapeseed oil preserved the favourable n-3/n-6 ratio without increasing the saturated fatty acids (SFA). Frying with lard and butter preserved the n-3/n-6...

Effect of process parameters on slowly digestible and resistant starch content in extrudatesOriginal Paper

Petra Smrčková, Meltem Saglamtas, Taťána Hofmanová, Jaroslav Koláček, David Chena, Evžen Šárka

Czech J. Food Sci., 2014, 32(5):503-508 | DOI: 10.17221/162/2014-CJFS  

A laboratory single-screw Kompaktextruder KE 19/25 was used at speeds 120-140 rpm of the screw with either a 2 : 1 or 3 : 1 compression ratio; the head had a 3 or 4 mm die. The temperature of the head was set at 131-144°C. The applied raw materials were maize grits, and mixtures with wheat starch, pea flour or chemically modified starch. Input mixtures differed in water addition (50 or 100 g water/kg). The highest amount of resistant starch (3.1% per total starch) in extrudate was found for mixture of pea flour and maize grits (with addition of 100 g water/kg of dry mixture), the output(extrudate)/input(mixture) ratio of the resistant starch was 45.8%....

Differentiation between fresh and thawed chicken meat by the measurement of aconitase activityOriginal Paper

Tereza ŠKORPILOVÁ, Anna ŠIMONIOVÁ, Bo-Anne ROHLÍK, Petr PIPEK

Czech J. Food Sci., 2014, 32(5):509-513 | DOI: 10.17221/356/2013-CJFS  

hypothesis, a method was developed to distinguish fresh meat from frozen/thawed meat. Another goal of this study was to compare the activity of mitochondrial enzyme aconitase in meat under different storage conditions. Despite the theory, the detected enzyme was despite the theory also found in the exudate of fresh meat. However, comparing the enzyme activity measured in fresh meat towith that measured in thawed meat, it is obvious that the enzyme activity in frozen/thawed meat is significantly higher. It was further found that the values of aconitase activity also vary in different anatomical parts of chicken meat. This might be caused by slightly...

Relationship between intrinsic viscosity, thermal and retrogradation properties of amylose and amylopectinOriginal Paper

Shifeng YU, Jing XU, Yongchun ZHANG, Narasimha Kumar KOPPARAPU

Czech J. Food Sci., 2014, 32(5):514-520 | DOI: 10.17221/394/2013-CJFS  

The relationships between intrinsic viscosity and some properties of amylose and amylopectin were investigated. The intrinsic viscosities determined by Ubbelohde viscometer for rice, maize, wrinkled pea and potato amyloses were 46.28 ± 0.30, 123.94 ± 0.62, 136.82 ± 0.70, and 167.00 ± 1.10 ml/g, respectively; and the intrinsic viscosities of rice, maize, wrinkled pea and potato amylopectins were 77.28 ± 0.90, 154.50 ± 1.10, 162.56 ± 1.20 and 178.00 ± 1.00 ml/g, respectively. The thermal and retrogradation properties of amylose and amylopectin were investigated by differential scanning calorimeter (DSC). Results...