Authors:Zs. Guld, A. Rácz, H. Tima, M. Kállay, and D. Nyitrainé Sárdy
, Y. , Yoshihiro , Y. & Masao , O. ( 2004 ): Changes in concentrations of resveratrol and its related compounds in red wine during alcoholic and malolactic fermentation . J. Jpn. Soc. Food Sci. , 51 ( 5 ), 274 – 278
Carrot is an important source of sugars. The objective of this study was to investigate the effects of water supply (precipitation + irrigation) on the concentration and ratio of fructose, glucose, and sucrose in carrot. Irrigation did not decrease the dry matter content and the summed concentration of the three measured sugars. Glucose accumulation was not influenced either by irrigation or by year. Low amount of precipitation during the early growing period was detrimental for fructose accumulation. Irrigation enhanced sucrose concentration, presumably by ensuring better photosynthetic activity. However, dry and hot weather during the irrigation cut-off period in 2011 also resulted in increased sucrose accumulation, presumably as a stress effect. It was found that irrigation did not influence the ratio of the three investigated saccharides at all, and even the growing year had just a slight effect on that.
Authors:J. Jakopic, A. Solar, M. Colaric, M. Hudina, R. Veberic, and F. Stampar
The influence of the ethanol concentrations on the phenolic content was analysed in walnut liqueur, which is traditionally prepared from green walnut fruits. At the end of June, green walnut fruits from cultivars Elit and Franquette were picked and steeped into three concentrations (40, 60 and 96%) of ethanol. In the walnut alcoholic drink (liqueur), total phenolic content was measured using spectrophotometer. Furthermore, twelve individual phenolics were investigated using HPLC with PDA detector such as gallic, protocatechuic, syringic, ellagic, sinapic,
-coumaric, chlorogenic, vanillic and caffeic acid, (+)-catechin, 1,4-naphthoquinone and juglone. The content of total phenolics increased with increasing ethanol concentration. Similar results were achieved for some individual phenolic compounds such as protocatechuic, sinapic and
-coumaric acid as well as 1,4-naphthoquinone. The levels of some other phenolic content were highest at 40% ethanol and lowest at 96% ethanol. This was exhibited for gallic, chlorogenic, vanillic and syringic acid, (+)-catechin and juglone.
Authors:Peter Kapalo, Florin Domnita, and Jan Lojkovics
The aim of the paper is to determine a methodology for calculating the needed airflow rate (including fresh air) in an occupied room, based on carbon dioxide measurement and calculation, in order to maintain the comfort indoor air quality. The calculated airflow rate should optimize the investment and the operating costs of HVAC equipment. In the work there are analyzed the calculation methods used to determine the ventilation airflow rate. It is presented the methodology for calculating the ventilation airflow rate for a room with people inside by using the measured values of carbon dioxide concentration. The connection between carbon dioxide concentration and ventilation airflow rate is verified by experimental measurements. This methodology is applicable in Slovakia because it complies with all current standards. The result obtained by using this calculation method is almost the same with that achieved from experimental measurements. To confirm the results, it is presented a case study of an office with occupants, in which the ventilation airflow rate calculation method is applied.In the article only a part from the total work is presented. The experimental measurements were carried out from 2011 to 2014. Approximately 54 measurements were covering total days or weeks. The following factors have been measured: indoor air temperature, outdoor air temperature, relative humidity of indoor air, relative humidity of outdoor air, concentration of CO2 in indoor air, concentration of CO2 in outdoor air, pressure difference and wind velocity. Ventilation by infiltration was calculated based on these factors using several methodologies. The methodology of measurement is not subject to the article. In this article only one aspect is investigated: CO2 concentration.
The total concentrations of the Ʃ16 polycyclic aromatic hydrocarbons (PAHs) were examined in some samples of baked ready-to-eat foods (cake, sausage roll, meat pie, burger, and bread) with a view to provide information on the hazards associated with the consumption of these hawked street foods. The measurements were performed by using a gas chromatograph-mass spectrometer (GC-MS) after hexane/dichloromethane extraction and clean-up. The total concentrations of the PAHs in these samples of ready-to-eat baked foods ranged from 427.4 to 1224 μg kg–1, 289.9 to 853.7 μg kg–1, 574.4 to 2333 μg kg–1, 364.6 to 2906 μg kg–1, and 15.7 to 213.1 μg kg–1 for cake, sausage roll, meat pie, burger, and bread, respectively. The results indicated that these baked ready-to-eat foods were mainly contaminated with 2-, 3-, and 4-ring PAHs. The concentrations of benzo(a)pyrene were less than 0.1 μg kg–1 in nineteen out of the twenty samples examined.
Our goal was to explore the interactions between the acoustic phenomena taking place in the ultrasound field, the concentration of the biological particles of the ultrasound field, and the cell biology effects of these interactions. Using output power of 9 W cm-2 and frequency of 1.117 MHz, the concentration was determined, expressed in g l-1, of lyophilized Saccharomyces cerevisiae baker's yeast needed for stopping cavitation in the sound field. Then by using multiples of the aforementioned concentration, we monitored the acoustic phenomena occurred in the sound field and, simultaneously, we examined the survival dynamics of the cells. Examined acoustic phenomena were the following: acoustic streaming, standing wave, and cavitation. Physical parameters (suspension density, dissolved oxygen, temperature) of the sound field had essential effect on the acoustic phenomena formed in the ultrasound field and on the threshold levels of their formation. The phenomena affected the composition of the material in the sound field, so an acoustical phenomenon - cell biological effect chain reaction took place during the radiation.