Czech Journal of Food Sciences, 2007 (vol. 25), issue 2
Biosynthesis of food constituents: Vitamins. 2. Water-soluble vitamins: Part 1 - a review
Jan Velíšek, Karel Cejpek
Czech J. Food Sci., 2007, 25(2):49-64 | DOI: 10.17221/756-CJFS 
This review article gives a survey of the generally accepted biosynthetic pathways that lead to water-soluble vitamins in microorganisms, plants and some animals. The biosynthetic pathways leading to the B-group vitamins (thiamin, riboflavin, nicotinic acid and nicotinamide, pantothenic acid, vitamin B6) are described in detail using the reaction schemes, sequences, and mechanisms with the enzymes involved and detailed explanations based on chemical principles and mechanisms. Keywords:
Evaluation of barley grass as a potential source of some nutritional substances
Ivana Paulíčková, Jaroslava Ehrenbergerová, Vlasta Fiedlerová, Dana Gabrovská, Pavla Havlová, Marie Holasová, Jiří Kopáček, Jarmila Ouhrabková, Jitka Pinkrová, Jana Rysová, Kateřina Vaculová, Renata Winterová
Czech J. Food Sci., 2007, 25(2):65-72 | DOI: 10.17221/754-CJFS
Barley green matter was analysed for the contents of vitamin C, total polyphenols, phenolic compounds, proteins, amino acids, and saccharides; the activity of catalase was also determined. The contents of vitamin C, total polyphenols, and ferulic acid decreased with the age of barley plants. The influence of the variety has not been proved unequivocally. The contents of vitamin C between 0.107-6.357 g/kg DM, of total polyphenols between 17.167-35.559 g/kg DM, and of ferulic acid between 0-5.916 g/kg DM were found. Catalase activity amounted to 4.5-29.7 TSU. The monosaccharide profile showed high contents of glucose (15.40-88.40 g/kg DM) and fructose...
Antioxidant and radical scavenging activities of a barley crude extract and its fraction
Ryszard Amarowicz, Zofia Żegarska, Ronald B. Pegg, Magdalena Karamać, Agnieszka Kosińska
Czech J. Food Sci., 2007, 25(2):73-80 | DOI: 10.17221/755-CJFS
Phenolic compounds were extracted from the Candle variety of hull-less waxy barley with 80% (v/v) methanol to yield a crude preparation. Seven fractions (I-VII) were separated from the barley extract so obtained on a Sephadex LH-20 column using methanol as the mobile phase. Nearly 80% of the phenolics extracted from barley were comprised in the first three fractions. The measurements of the antioxidant activity using a β-carotene-linoleate model system, radical scavenging capacity against DPP*, and reducing power based on the reduction of a Fe3+/K3Fe(CN)6 complex to the ferrous state were assessed in the barley...
Screening of antimicrobial activity of essential oil and methanol extract of Satureja hortensis on foodborne bacteria and fungi
Ahmet Adiguzel, Hakan Ozer, Hamdullah Kilic, Bulent Cetin
Czech J. Food Sci., 2007, 25(2):81-89 | DOI: 10.17221/753-CJFS
The present work reports the in vitro antimicrobial activities of the essential oil and methanol extract from Satureja hortensis as well as the content of its essential oil. The chemical composition of hydrodistilled essential oil of Satureja hortensis was analysed by means of GC-MS. Thirty constituents were identified. The main constituents of the oil were thymol (40.54%), γ-terpinene (18.56%), carvacrol (13.98%), and p-cymene (8.97). The essential oil of Satureja hortensis exhibited the activity against 25 bacteria, 8 fungi, and a yeast, C. albicans; exerting the Minimum Inhibitory Concentration values (MIC)...
Ultrasonic effect on pH, electric conductivity, and tissue surface of button mushrooms, Brussels sprouts and cauliflower.
Anet Režek Jambrak, Timothy J. Mason, Larysa Paniwnyk, Vesna Lelas
Czech J. Food Sci., 2007, 25(2):90-99 | DOI: 10.17221/757-CJFS
The aim of this work was to use ultrasound pre-treatment as a potential method prior to the subsequent processing in the food industry, for button mushrooms, Brussels sprouts, and cauliflower in order to observe the impact of ultrasound on the vegetable surrounding media properties in the processing conditions. The samples treated with 20 kHz probe and 40 kHz bath for 3 and 10 min were compared with blanched (80°C/3 min) and untreated samples. The effect was followed of ultrasound and blanching treatments on pH, electrical conductivity, and temperature changes. The effect of ultrasound on the sample tissue surface was also studied. The pH decreased...