scholarly journals Investigation of total polyphenol, antioxidant activity, and levels of metals in Ethiopian commercial beers

2020 ◽  
Vol 6 (1) ◽  
pp. 1824336
Author(s):  
Molla Tefera ◽  
Daniel Ayele
2019 ◽  
pp. 7-14
Author(s):  
Hai Trieu Ly ◽  
Tuan Anh Vo ◽  
Viet Hong Phong Nguyen ◽  
Thi My Sa Pham ◽  
Bich Thao Lam ◽  
...  

Background: The natural antioxidants have an important role in the prevention of many diseases. The aim of study is to investigate phytochemical components, antioxidant activity and acute oral toxicity of Pomegranate (Punica granatum L.) fruit peel (PFP) extract. Materials and methods: Phytochemicals of PFP were determined by qualitative chemical tests, thin layer chromatography, total polyphenol and flavonoid contents. The PFP extract was evaluated for antioxidant activity by DPPH assay and MDA assay. In vivo acute oral toxicity test was conducted using Karber-Behrens method to determine LD50. Results: Results illustrated that PFP mainly contains flavonoids, alkaloids, tannins, triterpenes, saponins, and coumarins. PFP extract exhibited the total polyphenol and flavonoid contents with 189.97 mg gallic acid equivalent/g dry weight and 9.42 mg quercetin equivalent/g dry weight, respectively. The DPPH free radical scavenging and anti-lipid peroxidation activities of PFP extract were expressed with IC50 value of 4.80 μg/mL and 0.38 μg/ mL, sequentially. Simultaneously, the Dmax (the maximum dose administered to mice that no toxicity was observed) of PFP extract was determined to be 21.28 g/kg, equivalent to 35.64 g dried herb. Conclusion: The PFP extract is relatively safe and revealed high antioxidant activity. Key words: Punica granatum L.; polyphenols; flavonoids; gallic acid; quercetin; antioxidant activity; acute oral toxicity


2017 ◽  
Vol 68 (3) ◽  
pp. 474-477
Author(s):  
Lacramioara Oprica ◽  
Doina Atofanei ◽  
Vladimir Poroch

The amounts of anthocyanins, flavonoids, total polyphenol and ascorbic acid in seven apple cultivars from Romania were investigated. The amounts of polyphenol and flavonoids in pulp and skin of apple cultivars ranged between 17.18�7.52 mg GAE/g DW and 20.10�11.06 mg CE/g DW as well as 3.64�1.18 mg GAE/g DW and 10.31�5.57 mg CE/g DW, respectively. The highest and smallest values of ascorbic acid both in the skin and the pulp were observed in the cultivars Mutsu and Starkrimson. The anthocyanin content is positively correlated with the colour intensity of the apple epicarp, being about three-fold higher in Prima than Golden Delicious cultivar. The better antioxidant activity provided by the content of polyphenol, ascorbic acid and flavonoids was in apple fruits of Mutsu cultivar and for this reason it should be regarded as a valuable source of antioxidants.


RSC Advances ◽  
2021 ◽  
Vol 11 (19) ◽  
pp. 11457-11467
Author(s):  
Himangshu Deka ◽  
Podma Pollov Sarmah ◽  
Arundhuti Devi ◽  
Pradip Tamuly ◽  
Tanmoy Karak

Changes in catechins, caffeine, total polyphenol, theaflavins, and antioxidant activity during CTC processing of black tea from North East India cultivar were studied. Total polyphenol decreased up to 37% with the formation of theaflavins up to 1.8%.


2013 ◽  
Vol 30 (3) ◽  
pp. 263-269 ◽  
Author(s):  
Renata Kazimierczak ◽  
Ewelina Hallmann ◽  
Anna Rusaczonek ◽  
Ewa Rembiałkowska

AbstractAmong infusions of green teabags and leafy green teas from organic and non-organic production systems we measured and compared the content of phenolic acids, flavonols and total polyphenols by spectrophotometry, the content of tannins by titration and the content of caffeine by high-performance liquid chromatography (HPLC). In addition, the antioxidant activity of the infusions was determined by spectrophotometry. The results obtained have shown that organic teas contained significantly more flavonols and tannins. However, the content of phenolic acids was higher in non-organic teas. The teas from organic and non-organic production did not differ in terms of total polyphenol content and antioxidant activity. There were no differences in leaf teas in relation to the teabags in contents of phenolic acids, tannins and total polyphenols. Organic teas had higher content of catechin C than the non-organic ones, but at the same time non-organic teas had more epigallocatechin 3-gallate (EGCG) in comparison to organic teas. Epigallocatechin (EGC) and epicatechin (EC) were not found to be different between the two groups of tea. Catechin was found to be significantly higher in teabags, while the EGCG was higher in leaf teas. The reason for this may be the oxidation of teabags, which have a greater exposed surface area. There was no appreciable effect of the form of tea on the content of tannins, caffeine, flavonols, phenolic acids, total polyphenols, EGC and EC as well as the antioxidant activity of the tea infusions examined.


2016 ◽  
Vol 34 (No. 5) ◽  
pp. 439-444 ◽  
Author(s):  
Balík Josef ◽  
Híc Pavel ◽  
Kulichová Jana ◽  
Novotná Pavla ◽  
Tříska Jan ◽  
...  

Red and white wines [Grüner Veltliner white wine and Blue Limberger (Blaufränkisch) red wine (vintage 2013)] were enriched with lignan hydroxymatairesinol originated from spruce knots. These spruce knots with removed resin were extracted with ethyl alcohol of agricultural origin. Ethanol extracts of lignans were then used to enrich wine sorts. Enriched wines were stored for 13 months. At 2, 6, and 13 months, samples were taken and subjected to a variety of analyses and sensory evaluations. Analyses included 7-hydroxymatairesinol and alpha-conidendrin lignan content, antioxidant activity (as determined by FRAP), total polyphenols, and sensory evaluation. The obtained data were evaluated using the analysis of variance to determine which factors e.g. wine type, quantity of added lignan extracts, additional sugar, method of preservation, and storage time had the most significant influence on lignan content, antioxidant activity and polyphenol content. In all cases the lignan content in the wines was significantly influenced by the addition of lignan extracts. After one year of storage, lignan contents changed only moderately and added lignans were stable in stored wines. Total polyphenol content in wines and the antioxidant activity of wines were significantly influenced by the type of wine (i.e., red or white). The presented method of wine enrichment with lignans opens the door for the production of extra quality wines.


2010 ◽  
Vol 5 (2) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Gábor Janicsák ◽  
István Zupkó ◽  
Imre Máthé ◽  
Judit Hohmann

The lipid peroxidation-inhibiting activities of aqueous methanolic extracts of eleven Salvia species (Fam. Lamiaceae) were evaluated in an enzyme-independent biological system. The total polyphenol contents and the amounts of the most abundant phenoloids of the genus, caffeic and rosmarinic acids, were also determined. The EC50 values of the extracts displayed substantial differences. All of the investigated species except S. jurisicii (EC50 191.2 μg/mL) exhibited higher activities than that of ascorbic acid (EC50 123.8 μg/mL), the reference compound. Among the studied species, S. scabiosifolia (EC50 5.4 μg/mL) demonstrated the highest effect, followed in sequence by S. dumetorum, S. transsylvanica, S. officinalis l albiflora, S. nemorosa l albiflora and S. recognita (EC50 6.5 – 10.2 μg/mL). The close correlation was confirmed between the antioxidant activities and the total phenol contents of the extracts. For caffeic and rosmarinic acids, the correlation was much weaker, indicating the important role of other polyphenols in the antioxidant activity.


Fermentation ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 29 ◽  
Author(s):  
Mesfin Haile ◽  
Won Kang

We examined the antioxidant activity, total polyphenol content (TPC), total flavonoid content (TFC), total tannin content (TTC) and physical characteristics of green coffee beans fermented with selected yeasts. There was no significant (p > 0.05) interaction effect between yeast-fermented coffee extracts and duration of fermentation on antioxidant activity (oxygen radical absorbance capacity [ORAC] and superoxide dismutase-like [SOD-like] activity). However, the mean of the antioxidant activity (ORAC and SOD-like activity) significantly (p < 0.05) increased in the fermented coffee extracts compared to unfermented coffee. There were significant (p < 0.05) interaction effects between yeast-fermented coffee extracts and duration of fermentation (24 h and 48 h) on the TPC, TFC, TTC and pH of the fermented solution and on the colors of the ground-roasted coffee. The TPC showed a pattern of increase in samples Ferm-1 and Ferm-3 as fermentation time increased from 24 h to 48 h. However, a decreasing TPC trend was observed in Ferm-2 as the number of fermentation hours increased from 24 to 48. The fermented coffee beans had a significantly higher flavonoid content than the unfermented coffee beans, while fermentation significantly decreased the tannin content compared to that in unfermented coffee.


Author(s):  
Sanda ANDREI ◽  
Andrea BUNEA ◽  
Constantin BELE ◽  
Cristina TUDOR ◽  
Adela PINTEA

The chlorophylls, carotenoids, total polyphenols contents and antioxidant activity in fresh and stored Parsley, celery and dill leaves were comparatively determined by spectrophotometric and high performance liquid chromatography (HPLC) methods. Results indicated that freezing does not induce significant changes in chlorophyll concentration. Drying induces significant decreases, varying according to the analyzed plant; parsley (60%), followed by dill (56.4%) and celery (45.3%). The carotenoids identified in all plants were lutein, b-carotene and cis-β-carotene. Fresh parsley leaves showed the highest total carotenoid concentration (21.64 mg/100g FW), followed by celery (15.41 mg/100g FW) and dill (14.95 mg/100g FW). Total polyphenols had an average concentration of 2.15 mg/g FW in parsley; 2.7 mg/g FW in dill and almost the double, 4.13 mg/g FW in celery. Drying of leaves induced a decrease with approximately 50% of the total polyphenol concentration, while freezing, did not significantly affect it. The highest antioxidant activity was observed in the dill, followed by parsley and celery. In both types of methods (freezing and drying in the oven), decreases in antioxidant activity were observed.


2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Eun-Sun Hwang

Abstract Objectives Cauliflower is one of the cruciferous vegetables and contains various physiologically active substances such as glucosinolates, polyphenols, and flavonoids. Unlike ordinary vegetables, cruciferous vegetables are often consumed by cooking through heat treatment. The purpose of this study was to investigate the effects of different heating procedures, in particular steaming and boiling, on glucosinolate, total polyphenol, and total flavonoid concentrations in cauliflower. In addition, antioxidant activity was compared between fresh uncooked, steamed, and boiled cauliflower, which are the main methods of preparing cauliflower before consumption. Methods Glucosinolates in uncooked, steamed, and boiled cauliflower were subjected to high-pressure liquid chromatography. Total phenolic and total flavonoid content and antioxidant activities in cauliflower extracted in both water and 80% ethanol were determined. Results Eight glucosinolate peaks were detected in cauliflower representing glucoiberin, progoitrin, glucoraphanin, sinigrin, gluconapin, glucoiberverin, glucobrassicin, and gluconasturtiin. Boiling cauliflower significantly decreased the glucosinolate, total polyphenol, and total flavonoid concentrations compared to those of uncooked or steamed cauliflower. The results clearly indicated that health-promoting compounds in cauliflower are significantly affected by different cooking methods, showing that uncooked > steamed > boiled. The amounts of total polyphenols and total flavonoids contained within uncooked cauliflower extracted by 80% ethanol were higher than those in the steamed and boiled extracts. The highest antioxidant activity was observed in uncooked cauliflower extracted in 80% ethanol compared to that of water extracts at the same concentration. Steamed and boiled cauliflower extracts showed lower antioxidant activity. Conclusions Based on these results, fresh uncooked cauliflower is optimal in terms of the content of health-promoting compounds and antioxidant activity. It may be desirable to use steaming rather than boiling to minimize the loss of glucosinolates when storing, pretreating, processing, and cooking cruciferous vegetables. Funding Sources This research was supported by the Basic Science Research Program through the National Research Foundation of Korea.


Sign in / Sign up

Export Citation Format

Share Document