scholarly journals Electrochemical and Spectrophotometric Determination of Total Polyphenol Content in Croatian Apple Varieties

2017 ◽  
Vol 90 (2) ◽  
Author(s):  
Martina Medvidović-Kosanović ◽  
Anamarija Šter ◽  
Lidija Jakobek ◽  
Petra Krivak ◽  
Rebecca Mađarić
2021 ◽  
Author(s):  
Suciu Felicia ◽  
Roșca Adrian Cosmin ◽  
Lupu Carmen ◽  
Popescu Antoanela ◽  
Badea Victoria

"The history of medicinal plants is associated with the evolution of civilization. In all regions of the world, the history of nations shows that these plants have always occupied an important place in medicine, in cosmetic products, and culinary preparations. The paper aims to determine the total polyphenols in different parts of the species Lysimachia nummularia L. In our study, we focused on the extraction of polyphenolic compounds in different solvents. The solvents used in the extraction were: 40% ethanol, concentrated methanol, in water. The total polyphenol content was determined by spectrophotometric methods, a method from the European Pharmacopoeia 10.0, with minor modifications. The total polyphenol content of different extracts varied depending on the extraction process. Different parts of the plant and different solvents were used in the determinations carried out to establish the optimal extraction method for the organs of Lysimachia nummularia L."


2008 ◽  
Vol 59 (3) ◽  
pp. 205-212 ◽  
Author(s):  
Suzana Berend ◽  
Zorana Grabarić

Odredivanje polifenola u namirnicama metodom ubrizgavanja u protokU ovom radu predložena je modificirana automatizirana metoda ubrizgavanja u protok za odredivanje sadržaja ukupnih polifenola u namirnicama bazirana na Folin-Ciocalteauovoj reakciji u 0,5 mol L-1 NaOH. Metoda omogućuje automatiziranu analizu različitih uzoraka brzinom protoka 55 uzoraka na sat uz upotrebu galne kiseline kao standarda. Primjenom predložene metode na konkretne uzorke (bijelo i crno vino, zeleni, indijski te čaj od lipe, metvice i kamilice i bistri voćni sokovi od crnog ribiza i višnje), odreden je njihov "indeks ukupnih polifenola" s većom repetibilnošću za razliku od ranije objavljenih metoda, manje ovisno o razrjedenju uzorka. U odnosu na "batch" metodu, ova je metoda visoko tolerantna prema najčešćim interferentima (SO2, reducirajući šećeri i askorbinska kiselina). Rezultati dobiveni predloženom metodom pokazali su relativno slaganje s onima dobivenim referentnom Folin-Ciocalteauovom metodom.


2021 ◽  
Vol 11 (11) ◽  
pp. 5124
Author(s):  
Ovidiu Tița ◽  
Ecaterina Lengyel ◽  
Diana Ionela Stegăruș ◽  
Petre Săvescu ◽  
Alexandru Bogdan Ciubara ◽  
...  

Grape seeds are a by-product of the wine industry. They represent 38–52% of grape pomace and about 5% of the weight of grapes. The main objective of this study is to establish some important characteristics of grape seeds from red varieties cultivated in Romania. The analyzed grape varieties were Cabernet Sauvignon, Merlot, Pinot noir, Burgund Mare, Cadarcă, Syrah, Novac. The grape seeds were dried and ground and the following determinations were made: determination of total polyphenol content, antioxidant capacity, antiradical capacity and determination of phenolic compounds. The analyses were performed on the first day after obtaining the grape extract, on the 14th day and the 30th day. The obtained results demonstrate that all the analyzed samples have a high content of polyphenols and show antioxidant and antiradical capacity. The highest values were obtained on the first day after separation, drying, grinding and extraction of the grape seeds and began to decrease almost constantly in time, so that for 30 days from storage the values obtained could ensure good operating yields. The seeds from the Novac grape variety obtained the best results throughout the analysis period. In the case of the total polyphenol content, the average value of the three samples Novac was 394.57 mgGAE/g dry extract and the average value of antioxidant capacity was 284.35 mgAAE/g dry extract. The greatest antiradical capacity was presented by the seeds of the Syrah and Novac varieties. The average value of the three samples from the Syrah variety was 62.1%, and in the case of the Novac variety was 61.33%. The paper demonstrates the opportunity of superior capitalization of seeds from the seven grape varieties cultivated on the territory of Romania due to the characteristics it possesses. At present, there is a major interest of consumers in the most natural products, with a major contribution to increasing the body’s immunity. The use of natural compounds in the food and pharmaceutical industry can be an important alternative.


2000 ◽  
Vol 18 (No. 2) ◽  
pp. 71-74 ◽  
Author(s):  
J. Lachman ◽  
M. Orsák ◽  
V. Pivec ◽  
J. Kučera

Ascorbic acid (AA) and total polyphenol content (TP) are important plant antioxidants with many healthy effects, such as ”scavengers of free radicals”, they inhibit oxidation of low-density lipoproteins, lower cholesterol levels, decrease fragility of blood vessels and increase their permeability, decrease heart coronary risk, etc. One of important sources of these compounds in human nutrition are apples. In two years (1997 and 1998) was investigated ascorbic acid content (AA) and total polyphenol content (TP) in three apple varieties (Idared, Gloster and Ontario) cultivated under equal conditions on the experimental plot of Czech University of Agriculture in Prague-Suchdol. AA content was determined by titration method with 2,6-dichlorphenolindophenol and TP content spectrophotometrically with Folin-Ciocalteau’s reagent. In two years’ trials AA and TP contents were estimated immediately after harvest in September and then monthly during storage for six months at +5°C. Statistically high significant differences were determined both in AA and TP contents during storage period – there was observed meaningful AA and TP decrease. The highest antioxidant content showed in both years early variety Ontario (in average 12.05 mg/kg AA, 2011.5 mg/kg TP), the lowest semi-early variety Gloster (in average 5.45 mg/kg AA, 1738.0 mg/kg TP). In this context the variety Ontario is the most favourable. The highest decrease of AA content was in variety Ontario (–30.05 %rel), the lowest in variety Gloster (–22.93 %rel ); in TP contents were differences negligible (–27.14 and –27.82 %rel). In spite of this decrease were in Ontario variety both values after six months storage the most favourable (8.45 mg/kg AA, 1466.5 mg/kg TP). Results were statistically evaluated with F-test and t-test. There could be seen differences among varieties and years of cultivation, but these differences were under the level of statistical significance showing only apparent tendencies. While varietal differences in decreasing of AA content during storage were greater (in interval from –22.93 %rel in Gloster variety to –30.05 %rel in Ontario variety), decreasing of TP contents during storage was nearly the same (about –27 %rel of original content


2013 ◽  
Vol 31 (No. 6) ◽  
pp. 589-595 ◽  
Author(s):  
A. Vollmannová ◽  
E. Margitanová ◽  
T. Tóth ◽  
M. Timoracká ◽  
D. Urminská ◽  
...  

Five cultivars from each of the three types of pseudocereals, i.e. buckwheat, amaranth, and quinoa, were studied for total polyphenol and rutin contents as well as total antioxidant capacity of seeds. A spectrophotometric method was used for the determination of total polyphenol content (using the Folin-Ciocalteau reagent) and total antioxidant capacity (using DPPH). Rutin content in pseudocereal seeds was determined by HPLC. The determined total polyphenol content in seeds of buckwheat, amaranth, and quinoa cultivars was in the intervals of 15 874–71 359 mg/kg DM, 1381–2870 mg/kg DM, and 459–1839 mg/kg DM, respectively. Rutin content in buckwheat, amaranth, and quinoa seeds was in the intervals of 8722–17 125 mg/kg DM, 310–508 mg/kg DM, and 170–368 mg/kg DM,respectively. The presented results confirmed a statistically significant influence of cultivar on total polyphenol and rutin contents as well as on total antioxidant capacity of pseudocereal seeds.


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