Czech Journal of Food Sciences, 2002 (vol. 20), issue 6

Antioxidant activity of rye caryopses and embryos extracts

M. Karamać, R. Amarowicz, S. Weidner, S. Abe, F. Shahidi

Czech J. Food Sci., 2002, 20(6):209-214 | DOI: 10.17221/3533-CJFS  

Phenolic compounds were extracted with 80% methanol from caryopses and embryos of rye (cv. Dańkowskie Złote and Amilo). In all extracts, reducing power, scavenging effect on DPPH radical, and antioxidant activity in a β-carotene-linoleate model system were examined. The highest content of total phenolic compounds was noted in the extract from caryopses of Amilo (7.93 mg/g of extract). UV spectra of all extracts were characterised by maxima originated from phenolic acids (320, 326 and 328 nm), and by maxima at shorter wavelengths (272 and 274 nm) attributed to other phenolic compounds. All extracts showed a good antioxidant activity in a β-carotene-linoleate...

Use of transglutaminase for improvement of quality of pastry produced by frozen-dough technology

B. Hozová, J. Jančovičová, L. Dodok, V. Buchtová, L. Staruch

Czech J. Food Sci., 2002, 20(6):215-222 | DOI: 10.17221/3534-CJFS  

The improving effect on the quality of final products has been studied of the enzyme transglutaminase added in two concentrations, i.e. 4.5 mg or 7.5 mg/300 g of flour destined for the preparation of pastry dough. Changes of the sensory (sensory profile), nutritional (the contents of amino acids, especially that of lysine), and microbiological quality (total count, yeasts, moulds) were investigated as well as those of aw and pH values of the pastry produced from the freezer-stored dough (-18 ± 2°C). It has been found that the sensory quality is favourably affected by the addition of transglutaminase (TGM) in the amount of 4.5 mg/300...

Essential oil composition of Ocimum basilicum L. and Ocimum minimum L. in Turkey

Musa Özcan, Jean-Clause Chalchat

Czech J. Food Sci., 2002, 20(6):223-228 | DOI: 10.17221/3536-CJFS  

The constituents of essential oils isolated by hydrodistillation of the overground parts of Ocimum basilicum L. and Ocimum minimum L. from Turkey were examined by GC-MS. A total of 49 and 41 components, respectively, were identified accounting for 88.1% and 74.4% of the oils of O. basilicum and O. minimum, respectively. The oil of O. basilicum contained, as main components, methyl eugenol (78.02%), α-cubebene (6.17%), nerol (0.83%) and ε-muurolene (0.74%). Major compounds in the volatile oil of O. minimum were geranyl acetate (69.48%), terpinen-4-ol (2.35%) and octan-3-yl-acetate (0.72%)....

Effect of defatted soybean flour on the flavour of extruded mixtures with wheat flour

J. Pokorný, A. Farouk Mansour, F. Pudil, V. Janda

Czech J. Food Sci., 2002, 20(6):229-236 | DOI: 10.17221/3535-CJFS  

Mixtures of wheat semolina, 5% glucose and 0-30% defatted soybean flour were used for the preparation of extruded samples using a pilot plant single screw extruder, maximum temperature being 140°C. The browning reactions were only moderate, the intensities of the trichromatic a* coordinate increased, and some changes were observed in chroma and the odour difference ΔE*. The sensory acceptability improved by increasing the content of soybean flour, the odour intensity increased, and some changes were observed in the sensory profile. Volatile substances were isolated using a SPME procedure, and the volatiles were separated using a Fisons GLC 8000...

Influence of the amount of rennet, calcium chloride addition, temperature, and high-pressure treatment on the course of milk coagulation

A. Landfeld, P. Novotná, M. Houška

Czech J. Food Sci., 2002, 20(6):237-244 | DOI: 10.17221/3537-CJFS  

Coagulated gel was characterised using an oscillation rheometer Rheostress RS 150. The influence was monitored of the additions of rennet and CaCl2, of temperature, and of high-pressure treatment on the properties of coagulated gel. Parameters of coagulation were assessed, i.e. elastic modulus G', the time of the start of coagulation t0, and the time constant of congealation τ. In monitoring the influence of increasing additions of rennet and CaCl2, and of temperature increase, it was found that the time of the start of coagulation t0 and the time constant of congealation t decreased. The limiting shear storage modulus G'max was...