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Wpływ kształtu reaktora i parametrów ekstrakcji podkrytycznej na jakość ekstraktów otrzymanych z kory dębu (Quercus robur L.)

Kamiński Piotr, Tyśkiewicz Katarzyna, Fekner Zygmunt, Kobus Zbigniew, Gruba Marcin

Przemysł Chemiczny

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2024

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T. 103, nr 6

695--710

PL

Zaprojektowano ekstraktor (40 L) do pozyskiwania polifenoli i flawonoidów z kory dębu (Quercus robur L.) za pomocą wody w warunkach podkrytycznych. Aktywność antyoksydacyjną oceniano metodą zmiatania rodnika 2,2-difenylo-1-pikrylohydrazylowego DPPH. Do analizy ekstraktów wykorzystano spektrofotometrię UV-Vis. Stwierdzono istotną korelację między temperaturą procesu a jakością ekstraktu. Zarówno całkowita zawartość polifenoli i flawonoidów, jak i aktywność antyoksydacyjna wzrastały wraz ze wzrostem temp. odpowiednio do 117,2°C, 116,5°C i 123,2°C. Dalszy wzrost temperatury powodował pogorszenie jakości ekstraktu. Doświadczenia prowadzono wg planu Boksa i Behnkena.

EN

An extn. cell (40 L) was designed for obtaining polyphenols and flavonoids from bark of oak (Quercus robur L.) with water under subcrit. conditions. The antioxidant activity was assessed by using a 2,2-diphenyl-1-picrylhydrazyl radical scavenging method. The UV-Vis spectrophotometry was used for anal. of the exts. A high correlation between process temp. and ext. quality was found. Both total contents of polyphenols and flavonoids as well as the antioxidant activity increased with increasing temp. up to 117.2°C, 116.5°C, and 123.2°C, resp. Further increase in temp. resulted in deterioration of the ext. quality. The expts. were carried out according to the Box-Behnken method.

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Decomposition of Fine Woody Debris from Main Tree Species in Lowland Oak Forests

Ostrogović M. Z., Marjanović H., Balenović I., Sever K., Jazbec A.

Polish Journal of Ecology

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2015

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Vol. 63, nr 2

247--259

EN

Decomposition is an important carbon flux that must be accounted for in estimates of forest ecosystem carbon balance. Aim of this research is to provide estimate of fine woody debris decomposition rates for different tree species and sample sizes also taking into account the influence of specific microsite meteorological conditions on decomposition rates. In this paper we present results of the first two years of the experiment designed to last six years. Study was conducted in managed lowland oak forest in central Croatia. Decomposition rates (k) of fine woody debris (diameter 0.5–7 cm) for four species (Querus robur L., Carpinut betulus L., Alnus glutinosa Gaernt., Fraxinus angustifolia L.) in four size classes were estimated using litter bag method and mass loss equation of Olson (1963). Overall average k in our study was 0.182 ± 0.011 year-1. Results indicate that decomposition rate is affected by the size of the debris, with the smallest diameter branches (<1 cm) decomposing is significantly faster (k = 0.260 ± 0.018, P <0.05) than the larger one. Tree species from which debris had originated also affected decomposition, although to a lesser extent, with hornbeam samples having significantly (P <0.05) higher average decomposition rate (0.229 ± 0.028), compared to that of ash samples (0.141 ± 0.022). Proportion of variability in k explained by variables ‘species’ and ‘size class’ was assessed with general linear model (R2 = 0.644) also taking into account variables like soil temperature and soil water content. Sample size class explained 22.2%; species explained only 9.4%, while soil water content and temperature combined explained 32.8% of the variance of k. Rate constants obtained within this study might be useful in modelling ecosystem carbon balance for similar lowland forest ecosystems in Europe.

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Oak decline in a southern Finnish forest as affected by a drought sequence

Sohar K., Helama S., Läänelaid A., Raisio J., Tuomenvirta H.

Geochronometria

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2014

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Vol. 41, no. 1

92--103

EN

We investigated the decline of a pedunculate oak (Quercus robur L.) forest growing on shallow soil at the northern distributional limit of the species in southern Finland, using the dendro-climatic approach. About 200-year-old trees in three vigour classes – healthy, declining and dead – were sampled in 2008. Annual tree-ring, earlywood and latewood widths were measured and chro-nologies were established. The tree-ring data were correlated with monthly and seasonal climate data. Radial increment of oaks was positively related to the June and July precipitations. This was ex-pressed especially in total ring width and latewood width, whereas the earlywood was more influ-enced by the warmer winter and spring. Furthermore, the correlation between the current year ear-lywood width and the preceding year latewood width was higher than between the earlywood and latewood of the same year. The analyses showed that the dead oaks and part of the declining oaks had ceased growing during 2005-2007 after a decade-long summer drought series. This indicates a time lag in the oak dieback. The radial growth of the declining and the dead oaks had dropped already since the 1990s, while the healthy oaks had better long-term growth and higher adaptive capacity to climate variation.

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Evaluation of the effect of environmental variables on health condition of Quercus robur L. in parks

Krzyżaniak M., Świerk D., Urbański P., Walerzak M. T.

Ecological Chemistry and Engineering. S

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2013

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Vol. 20, nr 4

689--700

EN

Investigations concerned the effect of different environmental variables on health condition of English oak (Quercus robur L.). It was shown that in the public parks in the city of Poznan the health condition of the analysed species is good. It was stated that health condition of this species in the Poznan parks is influenced by the distance from the immediate city centre, vicinity of traffic arteries and gas emissions from the combustion of fossil fuels by households neighbouring with the parks. Although results recorded in this study confirm literature data concerning the effect of environmental variables on health condition of English oak (Quercus robur L.), it was shown that certain environmental variables have a greater effect on health condition of the analysed species in Poznan.

PL

Badania dotyczyły wpływu różnych zmiennych środowiskowych na stan zdrowotny dębu szypułkowego (Quercus robur L.). Wykazano, że na terenie parków publicznych Poznania stan zdrowotny omawianego gatunku jest dobry. Stwierdzono, że wpływ na stan zdrowotny tego gatunku w parkach Poznania mają: oddalenie od ścisłego centrum miasta, bliskość arterii komunikacyjnych oraz emisja gazów ze spalania paliw kopalnych przez sąsiadujące z parkami gospodarstwa domowe. Mimo że wyniki uzyskane w pracy potwierdzają dane literaturowe dotyczące wpływu zmiennych środowiskowych na stan zdrowotny dębu szypułkowego (Quercus robur L.), to wykazano, że niektóre zmienne środowiskowe mają większy wpływ na stan zdrowotny badanego gatunku w Poznaniu.