Czech Journal of Food Sciences, 2009 (vol. 27), issue 2
Quinoa - a rewiev
Michala JANCUROVÁ, Lucia MINAROVIČOVÁ, Alexander DANDÁR
Czech J. Food Sci., 2009, 27(2):71-79 | DOI: 10.17221/32/2008-CJFS 
The healthy lifestyle and appropriate nutrition are stressed nowadays. New foodstuffs are still investigated with the aim to improve the diet and conduce to a better health state of the population. Pseudocereals (amaranth, buckwheat, and quinoa) are convenient for this purpose. Their high nutritious and dietary quality meets the demands of the food industry and consumers. Our collective dealt with quinoa, a commodity of Andean, because quinoa is a good source of essential amino acids such as lysine and methionine. Quinoa contains relatively high quantities of vitamins (thiamin, vitamin C) and minerals.
Drinking water quality in the Czech Republic
Jana Říhová Ambrožová, Jana Hubáčková, Iva Čiháková
Czech J. Food Sci., 2009, 27(2):80-87 | DOI: 10.17221/155/2008-CJFS
The quality of water has to be controlled and monitored by drinking water suppliers during all stages of the treatment process from the water sources to the end of distribution systems. The research, performed in Czech Republic from 2006 to 2008, deals with the assessment of the affect of water tanks on the quality of water supplied to consumers, specifically from various points of view: microbiological, biological and physic-chemical changes in water accumulation. Also studied was the influence of the air on the quality of accumulated water (secondary contamination), the influence of the structural layout and hydraulic ratios. In the project quick...
Influence of process parameters and pre-treatments on quality and drying kinetics of apple samples
Stela JOKIĆ, Darko VELIĆ, Mate BILIĆ, Jasmina LUKINAC, Mirela PLANINIĆ, Ana BUCIĆ-KOJIĆ
Czech J. Food Sci., 2009, 27(2):88-94 | DOI: 10.17221/170/2008-CJFS
The aim of this research was to determine the influence of the process parameters and pre-treatment methods on the quality and drying kinetics of apple samples of the Florina variety using standard analytical methods: thermo-gravimetry, rehydration, colorimetry. The Apple samples were dried in a laboratory tray drier at different temperatures (50, 60, and 70°C), airflow velocities (1.5 m/s and 2.75 m/s), and pre-treatment methods (dipping in 0.5% ascorbic acid solution; 0.3% L-cysteine solution; 0.1% 4-hexyl resorcinol solution; 0.5% sodium metabisulfite solution; mixed solution of 0.05% 4-hexyl resorcinol and 0.5% sodium metabisulfite; blanching...
Mathematical investigation of the effects of slicing on the osmotic dehydration of sphere and cylinder shaped fruits
Mohammad SIROUSAZAR, Akbar MOHAMMADI-DOUST, Bahram Fathi ACHACHLOUEI
Czech J. Food Sci., 2009, 27(2):95-101 | DOI: 10.17221/72/2008-CJFS
The dehydration kinetics of the fruits with special geometries, i.e. spherical and cylindrical (e.g. apple, peach, banana, pineapple, etc.), were studied based on mathematical methods. The influence of the size reduction (slicing) of these fruits into smaller rings was also investigated. The mathematical modelling was performed based on the Fick's second law. The results showed that increasing the value of the water diffusion coefficient in fruit (for instance, via increasing the process temperature) promotes faster water migration from the fruit. Mathematical modelling also showed that the characteristic length of fruits (radius) is in an inverse...
Microbiological, chemical, and sensory assessment of Pacific oysters (Crassostrea gigas) stored at different temperatures
Rong Cao, Chang-Hu Xue, Qi Liu, Yong Xue
Czech J. Food Sci., 2009, 27(2):102-108 | DOI: 10.17221/166/2008-CJFS
The changes were studied in microbiological, chemical, and sensory properties of Pacific oysters stored at 10°C, 5°C, and 0°C. Pseudomonas (22%) and Vibrionaceae (20%) species were dominant in raw oysters. The dominant bacteria found in the spoiled samples were Pseudomonas regardless of the storage temperature. During storage, rapid increases in aerobic plate count (APC) values of the samples stored at 10°C and 5°C were observed, while no obvious lag phases were detected. With the samples stored at 0°C, a decrease in APC value during the first 4 days and a lag phase of about 6 days were observed. The APC values of the samples stored...
Antioxidant activity of phenolic fractions of Mallotus philippinensis bark extract
Muhammad ARFAN, Hazrat AMIN, Magdalena KARAMAĆ, Agnieszka KOSIŃSKA, Wiesław WICZKOWSKI, Ryszard AMAROWICZ
Czech J. Food Sci., 2009, 27(2):109-117 | DOI: 10.17221/1056-CJFS
Phenolic compounds were extracted from Mallotus philippinensi bark using methanol. Six fractions (I-VI) were separated from the extract on a Sephadex LH-20 column using ethanol and acetone-water as the mobile phases and were evaluated for their total antioxidant activity, antiradical activity against DPPH* (2,2-diphenyl-1-picrylhydrazyl radical), and reducing power. The total phenolics and tannin contents in the fractions were determined. The content of total phenolics in the fractions ranged from 54 mg/g (fraction I) to 927 mg/g (fraction VI). Condensed tannins were detected in fractions II-VI. Total antioxidant activity (TAA) of...
Baroinactivation of Staphylococcus epidermidis - mathematical model and its verification using human and cow milk
Ljuba Schlemmerová, Milan Houška, Vladimir Špelina, Jan Strohalm, Aleš Landfeld, Hana ŠmuhaŘová, Ilona Němcová, Karel Kýhos, Jiřina Průchová, Pavla Novotná, Pavel Měřička
Czech J. Food Sci., 2009, 27(2):118-126 | DOI: 10.17221/1051-CJFS
Staphylococcus epidermidis, commonly found on the human skin, may contaminate human milk. High-pressure pasteurisation of human milk under normal temperature preserves the majority of its protective agents. The objective of this study was to acquire baroinactivation data and develop a model for model solutions of pH = 6.4 to 7.2 and water activity aw = 0.99, in which baroinactivation of Staphylococcus epidermidis takes place. Decontamination data manifested exponential kinetics and the resulting model was described by the following equations: Dp = Dp, ref × 10 (Pref - P)/Z, Z = -123.90 pH2...
Influence of soft cheese technology on the growth and enterotoxin production of Staphylococcus aureus
Lenka Necidová, Zora Šťástková, Markéta Pospíšilová, Bohumíra Janštová, Jan Strejček, Marta Dušková, Renáta Karpíšková
Czech J. Food Sci., 2009, 27(2):127-133 | DOI: 10.17221/131/2008-CJFS
The aim of this study was to monitor S. aureus growth and toxin production in soft cheese during the technological processing. In model experiments, raw milk was inoculated separately with five S. aureus strains isolated from milk and milk products. All the strains were producers of staphylococcal enterotoxins (SEs) of types A, B, or C. SEs were detected by the enzyme-linked fluorescence assay (ELFA) performed in the MiniVIDAS device. This study has shown that the amount of SEs varied with the tested strains and stages of the technological process. SEs were detected in soft cheese made from pasteurised milk inoculated with 2.9 × 105...
High pressure inactivation of Enterococcus faecium - modelling and verification
Aleš Landfeld, Jan Strohalm, Karel Kýhos, Jiřina Průchová, Milan Houška, Pavla Novotná, Ljuba Schlemmerová, Hana Šmuhařová, Vladimir Špelina, Pavel Čermák, Kveta Pavlišová, Pavel Měřicka
Czech J. Food Sci., 2009, 27(2):134-141 | DOI: 10.17221/1052-CJFS
High-pressure inactivation data were obtained for model working suspensions of Enterococcus faecium in saline solutions in pH range from 5.5 to 6.8, at water activity 0.99 (corresponding to the saline solution). The data were predicted for the pressure range of 450 MPa to 550 MPa, at the initial model suspension temperature 6-7°C prior to pressurising. The results indicate that E. faecium is a highly resistant organism under physiological pH values. With decreasing the substrate pH, the tolerance to the inactivation effects of high pressure decreased. The high-pressure inactivation proved ineffective for the above organism in the range...