Enzyme electrodes for determination of total phenolic capacity of red wines

2005 ◽  
Vol 98 (1) ◽  
pp. 521-524 ◽  
Author(s):  
S. Kıralp ◽  
A. Cirpan ◽  
L. Toppare
Keyword(s):  
Total Phenolic ◽  
Red Wines ◽  
Enzyme Electrodes

The Comparative Study of Equisetum pratense, E. sylvaticum, E. telmateia: Accumulation of Silicon, Antioxidant and Antimicrobial Screening

2019 ◽  
Vol 70 (7) ◽  
pp. 2519-2523
Author(s):  
Denisa Batir Marin ◽  
Oana Cioanca ◽  
Mihai Apostu ◽  
Cristina Gabriela Tuchilus ◽  
Cornelia Mircea ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Methanol Extract ◽  
Previous Treatment ◽  
Total Phenolic ◽  
Quantitative Chemical Analysis ◽  
Qualitative And Quantitative ◽  
Antioxidant And Antimicrobial Activity ◽  
The Comparative Study

The objective of the current study is represented by the determination of silica and a phytochemical screening of phenolic derivates of some Equisetum species. The antioxidant and antimicrobial activity for Equisetum pratense Ehrh.,, Equisetum sylvaticum L. and Equisetum telmateia Ehrh. (sin. Equisetum maximum Lam.) were also investigated. The concentration of silicon (Si) in plants was determined by the spectrophotometric method using previous treatment with NaOH 50% both for the stem and the nodal branches [1]. Results obtained varied from 95.12 to 162.10 SiO2 mg/g dry plant which represents 4.44% to 7.58% Si/100g dry sample. Two types of total extracts were obtained using different solvents and were subjected to qualitative and quantitative chemical analysis considering total phenolic content [2]. The highest concentration of investigated compounds was found in the methanolic extract, E. sylvaticum, 196.5mg/g dry sample. Antioxidant activity was monitored spectrophotometrically and expressed in terms of IC50 (�g/mL) [3]. Values gathered ranged from 261.7 to 429.5 �g/mL. The highest capacity to neutralized DPPH radicals was found in E. sylvaticum. In vitro antimicrobial activity was determined using difusimetric method [4]. Testing was performed on four microorganisms: three strains of bacteria and one species of fungi. Different effects were noticed against the bacteria, furthermore the methanol extract appeared to be most efficient. All extracts showed significand antimicrobial activity against Staphylococcus aureus (ATCC 25923) and Candida albicans (ATCC 90028) and weak to no activity against Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922).

Biochemical study of attached macroalgae from the Madeira Archipelago and beach-cast macroalgae from the Canary Islands: multivariate analysis to determine bioresource potential

2020 ◽  
Vol 63 (3) ◽  
pp. 283-298
Author(s):  
Nuno Nunes ◽  
Sofia Valente ◽  
Sónia Ferraz ◽  
Maria Carmo Barreto ◽  
Miguel A.A. Pinheiro de Carvalho
Keyword(s):  
Biochemical Study ◽  
Algal Species ◽  
Biochemical Properties ◽  
Total Phenolic ◽  
Total Carotenoids ◽  
The North ◽  
Madeira Archipelago ◽  
Total Carbohydrates ◽  
Beach Cast

AbstractFifteen attached macroalgae from the Madeira Archipelago, comprising three green, three red and nine brown algal species, as well as two beach-cast macroalgal samples, collected along the north shore of Gran Canaria, were assessed for their biochemical properties. The analysis included the determination of total minerals, total carbohydrates, protein, lipids, chlorophyll a, total carotenoids, total phenolic content, fucoxanthin and phycobilins (allophycocyanin, phycocyanin and phycoerythrin). The results showed a high variability of biochemical composition, allowing for the targetting of specific bioresources for particular purposes, including functional foods. This work provides the foundation for a biorefinery strategy implementation plan, for which specific macroalgae may be targeted for valuable and beneficial compounds.

scholarly journals Determination of antioxidant activity and phenolic compounds for basic standardization of Turkish propolis

2021 ◽  
Vol 64 (1) ◽  
Author(s):  
Aslı Özkök ◽  
Merve Keskin ◽  
Aslı Elif Tanuğur Samancı ◽  
Elif Yorulmaz Önder ◽  
Çiğdem Takma
Keyword(s):  
Antioxidant Capacity ◽  
Caffeic Acid ◽  
Caffeic Acid Phenethyl Ester ◽  
Total Phenolic ◽  
Scaling Analysis ◽  
Flavonoid Content ◽  
Multidimensional Scaling Analysis ◽  
Flavonoid Quercetin ◽  
Phenolic And Flavonoid

AbstractThis study aimed to determine the standard amount of antioxidant content and compounds of the propolis for the standardization of propolis. For this purpose, the total flavonoids, total phenolic, CUPRAC antioxidant capacity content and the diversity of phenolic and flavonoid components of these propolis samples were found by HPLC determined at the 23 propolis samples which were collected different regions of Turkey. Beside that, the similarities and differences of these 23 provinces to each other according to their antioxidant capacities were investigated by multidimensional scaling analysis. The total flavonoid content in the propolis samples were determined between 21.28 and 152.56 mg CE/g. The total phenolic content in the propolis samples was found between 34.53 mg and 259.4 mg GAE/g. CUPRAC antioxidant capacity of the propolis samples and antioxidant range was found from 95.35 to 710.43 mg TE/g. Also, 4 flavonoid [Quercetin (min.1.12–max.4.14 mg/g), Galangin (min.0.72–max.40.79 mg/g), Apigenin (min.1.07–max.17.35 mg/g), Pinocembrin (min.1.32–max.39.92 mg/g] and 6 phenolic acid [Caffeic acid (min.1.20–max.7.6 mg/g), p-Coumaric acid (min.1.26–max.4.47 mg/g), trans-Ferulic acid (min.1.28–max.4.92 mg/g), Protocatechuic acid (1.78 mg/g), trans-Cinnamic acid (min.1.05–max.3.83 mg/g), Caffeic Acid Phenethyl Ester (CAPE) (min.1.41–max.30.15 mg/g)] components were detected as mg/g, in different ratios in propolis samples collected from different regions. The feature of this study, so far, is to have the maximum number of samples representing the Turkish propolis, and so is thought to help to national and international propolis standard workings.

scholarly journals Wine origin authentication linked to terroir – wine fingerprint

2019 ◽  
Vol 15 ◽  
pp. 02033
Author(s):  
B. Gabel
Keyword(s):  
Pore Water ◽  
Isotope Composition ◽  
Food Product ◽  
Isotopic Signature ◽  
Original Method ◽  
Economic Problem ◽  
Red Wines ◽  
Table Grapes ◽  
Mineral Phases

Global wine and alcohol trade faces a serious economic problem linked to counterfeiting of these commodities. Recently applied authentication methods and techniques pose more difficulties for counterfeiters but they are apparently not effective once we consider economical losses identified by EU legal authorities. The presented solution links isotopic characteristics of the soil, plant, technological intermediate product and the final food product (wine, grapes) on the basis of 87Sr/86Sr isotopes ratios. For the isotopic signature of wines, the average isotope composition of the substrate cannot be a reliable indicator. Only the isotopic composition of pore water can, as it leaches various mineral phases at different stages and passes into vine root system. Instead of complicated sampling of pore water, an original method of preparing and processing soil samples and consequently must & wine samples was developed. Based on both, soil and biological material analysis, we can unquestionably determine not only geographical but also regional and local authenticity of the wine. Determination of red wines isotopic signature is more straightforward process in comparison to white wines, because of technologically different processing of grapes. That is the reason why, in case of white vines, the 87Sr/86Sr ratio of bentonites (natural purifier and absorbent useful in the process of winemaking) must also be taken into consideration. Results of analyses of Slovak wines from geographically diverse regions as well as from sites in close-by distances have clearly established reliability of presented concept, in which the soil is linked to the plant and to the final food product (wine or table grapes).

Simultaneous determination of lactose and glucose in milk using two working enzyme electrodes

Talanta ◽  
1994 ◽  
Vol 41 (6) ◽  
pp. 843-848 ◽  
Author(s):  
Takashi Katsu ◽  
Xianen Zhang ◽  
Garry A. Rechnitz
Keyword(s):  
Simultaneous Determination ◽  
Enzyme Electrodes

scholarly journals Polyphenolic compounds and essential oil analysis of selected species of the genus Thymus / Analýza fenolových zložiek a analýza silice vybraných druhov rodu Thymus

2015 ◽  
Vol 62 (s9) ◽  
pp. 12-17
Author(s):  
M. Kameníková ◽  
S. Fialová ◽  
A. Ťažký ◽  
I. Čičová
Keyword(s):  
Phenolic Compounds ◽  
Essential Oil ◽  
Spectrophotometric Method ◽  
Total Phenolics ◽  
Chemical Constituents ◽  
Aluminium Chloride ◽  
Total Phenolic ◽  
Oil Analysis ◽  
European Pharmacopoeia

Abstract The content of phenolic compounds (total phenolic compounds, tannins, flavonoids and anthocyanidins) of three species of thyme (Thymus pulegioides, Thymus pannonicus, Thymus praecox) of different origin (Bohemian-Moravian highlands, Křivoklat and Považsky Inovec) was determined using spectrophotometric methods of European Pharmacopoeia 8th edition. Furthermore, the determination of the content of essential oil and analysis of its constituents was realised. The amount of total phenolics was determined by a spectrophotometric method using the Folin-Ciocalteu reagent. Their content ranged from 3.87 to 8.86%. The content of tannins was established on a preliminary determination of the total phenolics, followed by adsorption of tannins on hide powder. The amount of tannins in our samples varied from 1.96 to 5.65%. The content of total flavonoids was determined by a spectrophotometric method using aluminium chloride. Quantitative analysis of flavonoids has shown that content in our samples ranged from 0.59 to 1.52% expressed as luteolin-7-O-glucoside (λ = 392 nm) and from 0.41 to 1.12% expressed as rutin (λ = 420 nm). Anthocyanins represent a small amount of total polyphenol content in Thymus species. In our samples, the content of anthocyanins expressed as cyanidin-3-O-glucoside varied from 0.02 to 0.1%. The determination of essential oil was realised by method of European Pharmacopoeia 8th edition. Its contents in our samples ranged from 0.2 to 0.75%. Gas chromatography-mass spectrometry was used for essential oil analysis. According to the presence of main monoterpene in Thymus essential oil, we can distinguish three chemotypes: thymol, carvacrol and linalool. Due to variations of chemical constituents of thyme essential oil, it was possible to observe a relationship between occurrence of certain chemotype and origin of sample. Differences in content of flavonoids have not shown a significant relationship to locality of origin.

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