Wyniki wyszukiwania - Biblioteka Nauki

1

THE INFLUENCE OF STORAGE TEMPERATURE AND UV-IRRADIATION ON FREE RADICAL SCAVENGING PROPERTIES OF ETHANOLIC EXTRACTS OF PROPOLIS

100%

Komosińska-Vassev K. , Olczyk P. , Ramos P. , Mencner L. , Derkacz A. , Waluga E. , Krysik K. , Olczyk K. , Pilawa B.

Acta Poloniae Pharmaceutica - Drug Research

|

2018

|

tom 74

|

nr 6

1833-1840

EN

The free radical scavenging activity of ethanolic extracts of propolis (EEP) at the concentrations of 3%, 7%, and 10% was examined. The impact of storage temperature and exposure to ultraviolet (UV) light on the interactions of extracts of propolis with the model DPPH free radicals was also determined. The quenching of an X-band electron paramagnetic resonance spectra of DPPH free radicals by the extracts stored at room temperature, heated at the temperature of 50 oC and exposed to UV-irradiation, were compared. The examined propolis ethanolic extracts revealed an antioxidative character. The storage of the samples at a higher temperature (50 oC) caused a decrease of the scavenging activity equaling to 7% and 10% EEP. UV-irradiation of the 3% EEP increased the quenching of DPPH free radical lines. The reverse effect was observed for the 7% and 10% propolis extracts. The 3% ethanolic extract of propolis is more stable for storage at 50ºC, and less than other analyzed EEP susceptible for UV-irradiation. Alterations of the antioxidative properties of the analyzed EEP and changes in the kinetics of their interactions with free radicals, indicate that 3%, 7%, and 10% propolis extracts should not be exposed to the temperature of 50 oC and UV-irradiation.

2

Free radical scavenging ability of sodium lignosulfonate and its application in food grade polypropylene

86%

Musajian D. , Hasan G. , He M. , Yimit M.

Polish Journal of Chemical Technology

|

2020

|

tom Vol. 22, nr 2

56--66

EN

Sodium lignosulfonate (SL) was prepared from waste of cotton lignin (CL) through hydrothermal reaction method. Orthogonal experiment was designed with value of OIT as objective function. Polypropylene (PP) is a polymer produced by the addition polymerization of propylene. It is a white waxy material with a transparent and light appearance, which is widely used in food and pharmaceutical packaging. The results of GPC and TG analysis revealed that SL has stable thermal properties, which means that SL has the potential to be an antioxidant for PP materials. In addition, the scavenging effects of CL and SL were studied. The obtained results exhibited that the SL can obviously increase the scavenging effect on free radicals and it is a kind of new synthetic antioxidant with antioxidant property, which could effectively delay the oxidation of PP. Subsequent rheological experiments proved that the SL/PP sample can improve the heat-resistant oxygen performance of PP under the thermal oxygen shearing environment. Combined with the effect of SL on the mechanical properties of PP before aging, SL has a stabilizing effect on PP thermal oxygen aging.

3

Free-radical scavenging activity of cosmetic plant extracts

86%

Malinowska P.

Towaroznawcze Problemy Jakości. Polskie Towarzystwo Towaroznawcze

|

2013

|

nr 1

4

Antioxidative potential of substances contained in cold pressed soybean oil and after each phase of refining process

72%

Kania M. , Michalak M. , Gogolewski M. , Hoffmann A.

Acta Scientiarum Polonorum. Technologia Alimentaria

|

2004

|

tom 03

|

nr 1

EN

This study is an investigation of determining the changes of scavenger capacity of DPPH* free radicals through substances contained in soybean cold pressed oil and in oils taken after individual phases of refinement. The content of tocopherols and phenolic compounds was determined. Scavenging of DPPH* was examined and the coefficient of antiradical activity (AE) was counted in order to objectively determine the potential. Cold pressed oil had the highest ability of scavenging of DPPH*. This oil also possessed the largest coefficient of antiradical efficiency (AE = 14.51•10-3). The largest quantity of tocopherols was observed in crude oil and phenolic compounds in cold pressed oil. It was affirmed that every next stage of refinement causes the decreasing of tocopherols and phenolic compounds content.

PL

Podjęto badania nad określeniem zmian zdolności wygaszania wolnych rodników DPPH przez substancje zawarte w oleju sojowym tłoczonym na zimno oraz w olejach pobranych po poszczególnych etapach rafinacji. Oznaczono zawartość tokoferoli oraz ogólną zawartość związków fenolowych. Zbadano zdolność wygaszania wolnych rodników DPPH* oraz dla obiektywnego wyznaczenia potencjału przeciwutleniającego obliczono współczynnik aktywności antyrodnikowej (AE). Najwyższą zdolność wygaszania DPPH* miały substancje zawarte w oleju tłoczonym na zimno. Olej ten miał także największy współczynnik aktywności antyrodnikowej (AE = 14,51•10-3). Największą ilość tokoferoli oznaczono w oleju surowym, a związków fenolowych w oleju tłoczonym na zimno. Stwierdzono, że każdy kolejny etap rafinacji powoduje obniżenie zawartości tokoferoli i związków fenolowych.

5

Effect of biologically active substances on antioxidant activity in rapeseed oil tested in accelerated oxidative process

58%

Kania M. , Michalak M. , Gogolewski M.

Rośliny Oleiste - Oilseed Crops

|

2005

|

tom 26

|

nr 1

6

Zdolnosc eliminowania wolnych rodnikow przez ekstrakty uzyskane z frakcji mlynarskich ziarna nieoplewionych i oplewionych form jeczmienia i owsa

44%

Woloch R.

Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin

|

2003

|

tom 229

263-270