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Antioxidant activity of extracts from defatted and non-defatted flax (Linum usitatissimum L.) seeds
(Lodz University of Technology Press, 2015) Brodowska, Katarzyna; Łodyga-Chruścińska, Elżbieta
Flax, Linum usitatissimum, is an annual plant and member of the Linaceae family [1]. Flax is rich in fats (41%), proteins (20%) and dietary fibre (28%). Seeds of flax are the richest source of alpha-linolenic acid, lignans and other nutritional components. Flaxseed oil contains interesting bioactive compounds other than the fats [2]. The aim of this study was to estimate the total polyphenol content (TPC), free radical scavenging activity, and ferric reducing antioxidant power (FRAP) in extracts from defatted and non-defatted flax seeds. The results clearly show the impact of fatty acids on the effectiveness of this research.
Determination of total contents of transition metals in selected granular black teas marketed in Poland
(Wydawnictwa Politechniki Łódzkiej, 2014) Sykuła, Anna; Brodowska, Katarzyna; Więdłocha, Marzenna
The total contents of metals in three granulated black tea samples marketed in Poland were determined. Four elements consisting transition metals (Ni, Cu, Zn and Fe) were analyzed using flame atomic absorption spectrophotometry (FAAS). All examined tea brands contain considerable contents of the studied transition metals. Among the tested transition metals Fe (242-589 mg kg-1) was the most abundant one in the granular black tea imported from India. The highest value of Fe was analyzed in the cheapest tea, the smallest in the most expensive. The other metals are less abundant than Fe, their values varied from 8.50-8.90 for Ni, 7.80-10.4 for Cu and 8.13-12.6 for Zn mg kg-1. The accuracy of the proposed method was assessed by determining the recovery of metals from analyzed tea samples using the standard addition method. Recovery assays of nickel, copper, zinc and iron were demonstrated satisfactory, mean recoveries 99.29, 100.31, 99.94 and 99.79 %, respectively.
Determination of total contents of transition metals in selected granular black teas marketed in Poland
(Wydawnictwo Politechniki Łódzkiej, 2014) Sykuła, Anna; Brodowska, Katarzyna; Więdłocha, Marzenna
The total contents of metals in three granulated black tea samples marketed in Poland were determined. Four elements consisting transition metals (Ni, Cu, Zn and Fe) were analyzed using flame atomic absorption spectrophotometry (FAAS). All examined tea brands contain considerable contents of the studied transition metals. Among the tested transition metals Fe (242-589 mg kg-1) was the most abundant one in the granular black tea imported from India. The highest value of Fe was analyzed in the cheapest tea, the smallest in the most expensive. The other metals are less abundant than Fe, their values varied from 8.50-8.90 for Ni, 7.80-10.4 for Cu and 8.13-12.6 for Zn mg kg-1. The accuracy of the proposed method was assessed by determining the recovery of metals from analyzed tea samples using the standard addition method. Recovery assays of nickel, copper, zinc and iron were demonstrated satisfactory, mean recoveries 99.29, 100.31, 99.94 and 99.79 %, respectively.
Naringenin complexes with copper ions: potentiometric studies.
(Wydawnictwo Politechniki Łódzkiej, 2013) Brodowska, Katarzyna
Flavanones belong to the group of active flavonoid compounds, rarely occurring in the plant kingdom and are found in many foodstuffs (naringenin and derivatives) and medicinal plant materials. Many studies have demonstrated a relationship between dietary intake of phenolic compounds and reduced risk of cancer and cardiovascular disease. Accordingly, during over several years, flavonoids have gained increasing interest and numerous studies have shown that they possess beneficial properties having a great influence on human health. Acid dissociation constants are believed to be the most useful physico-chemical parameters which describe the extent of ionization of functional groups as a function of pH. It is very important in research areas such as pharmaceutical drug discovery and development due to vital role in understanding the pharmacodynamic properties of new drug substances. Flavonoids are characterized by insolubility in water while they are soluble in organic solvents. Exploiting mixed solvents, especially organic solvent – water mixtures, enables a good alternative for researching on compounds which are inconspicuously soluble or insoluble in water. In this study the dissociation constant of naringenin and its complex with Cu(II) have been determined in aqueous – DMSO solvent mixtures to examine the dependence of their acid-base equilibria on number of substrates.