scholarly journals Impact of heat treatment and flavorings on the antioxidant capacity of black and green tea

Author(s):  
Zsanett Bodor ◽  
Bianka Pergel ◽  
Csilla Benedek

AbstractThe high antioxidant capacity of tea is well-known, but the effect of flavorings like honey or lemon has been less studied. Their antioxidants can interact with each other, the global result being also affected by the brewing temperature.The combined effect of heat (55 and 80 °C) and flavorings (acacia and honeydew honeys, lemon juice) on the total polyphenol, total flavonoid content and antioxidant capacity of black and green teas was studied.In many cases higher antioxidant capacity was obtained at 80 °C. Teas flavored with honeydew honey had higher antioxidant capacity than those containing acacia honey. Addition of lemon decreased the antioxidant capacity of tea with honey. No synergies were confirmed in any of the compositions investigated. Vitamin C content of lemon-containing black tea was reduced by half at 80 °C compared to tea brewed at 55 °C; while honey was shown to partly prevent this loss of ascorbic acid.

Author(s):  
Simona Ioana VICAS ◽  
Livia BANDICI ◽  
Alin Cristian TEUSDEA ◽  
Gheorghe Emil BANDICI

In this paper, our objective was to investigate extraction efficiency of polyphenols with antioxidant capacity from two varieties of grapes (white-Muscat Ottonel (MO) and red-Pinot Noir (PN)) using pulsed electric field (PEF). Grapes were harvested in the Crisana Santimreu vineyard in 2015. The grapes were declustered and crushed, and have been divided into three parts. A part was treated in PEF, the second one was homogenized, and then was treated in PEF and the last part remained untreated, representing the control samples. The bioactive compounds, like total polyphenol content and total flavonoid content, were determined by the spectrophotometric method. The antioxidant capacity of the samples was determined by three methods (DPPH, FRAPand TEAC). Our results show that the application of PEF to the crushed grapes increases the total polyphenol content 2.28 and 3.15 times and the total flavonoid content 7.17 and 5.29 times for MO and PN, respectively. Also, the antioxidant capacity was significantly increased when it was compared with the control sample. When the treatment in PEF was applied on homogenized grapes both bioactive compounds and antioxidant capacity were significantly increased compared to the samples treated in PEF for crushed grapes. In the present research work, we demonstrated that the application of PEF to two different grape varieties significantly increased the level of total polyphenols and flavonoids and also the antioxidant capacity. The application of PEF to homogenized grapes was more efficient.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Vijendren Krishnan ◽  
Syahida Ahmad ◽  
Maziah Mahmood

Plants from Gynura family was used in this study, namely,Gynura procumbensandGynura bicolor.Gynura procumbensis well known for its various medicinal properties such as antihyperglycaemic, antihyperlipidaemic, and antiulcerogenic; meanwhile,G. bicolorremains unexploited. Several nonenzymatic antioxidants methods were utilized to study the antioxidant capacity, which include ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, total flavonoid content, total phenolic content, and ascorbic acid content determination. DPPH assay revealsG. procumbensshoot as the lowest (66.885%) andG. procumbensroot as the highest (93.499%) DPPH radical inhibitor. In FRAP assay, reducing power was not detected inG. procumbensleaf callus (0.000 TEAC mg/g FW) wherebyG. procumbensroot exhibits the highest (1.103 TEAC mg/g FW) ferric reducing power. Total phenolic content and total flavonoid content exhibited similar trend for both the intact plants analysed. In all antioxidant assays,G. procumbenscallus culture exhibits very low antioxidant activity. However,G. procumbensroot exhibited highest phenolic content, flavonoid content, and ascorbic acid content with 4.957 TEAC mg/g FW, 543.529 QEµg/g FW, and 54.723 µg/g FW, respectively. This study reveals thatG. procumbensroot extract is a good source of natural antioxidant.


Author(s):  
Anis Nafisah Jamain ◽  
Norhaslinda Ridzwan ◽  
Mimie Noratiqah Jumli ◽  
Norhayati Abd Hadi ◽  
Mohd Adzim Khalili Rohin ◽  
...  

Aim: To evaluate the ash and moisture contents, total phenolic content, total flavonoid content, and antioxidant potential of Terengganu singgang extracts. Study Design: Experimental study. Place and Duration of Study: Central Laboratory, Tissue Culture Laboratory, Universiti Sultan Zainal Abidin, Terengganu between April 2019 and July 2019. Methodology: Samples comprised three types of singgang dishes, which were prepared, cooked, and then extracted with distilled water and ethanol (EtOH) in different strengths, 50%, 70%, and 100%. These singgang samples were chub mackerel (ST), Indian mackerel (SK), and a control sample with no fish(SC). Extracts were analyzed for their moisture and ash content. Also, the total phenolic content (TPC) was assayed using Folin-Ciocalteu reagent, while total flavonoid content (TFC) using AlCl3 colorimetric assay, and antioxidant activity using 1,1-Diphenyl-2-picrylhydrazyl (DPPH). The total antioxidant capacity (T-AOC) was also evaluated. Results: Experimental assays showed that the SC sample extracted in 100% EtOH produced the highest yield (3.7%). SK samples were lower than SC and ST in moisture content and ash content with 94.21%, 96.37% and 93.03% moisture content and 0.85%, 0.71%, and 0.96% ash content. Meanwhile, the extract of ST in 100% EtOH yielded the highest TPC (315.0 mg GAE/100g) and T-AC (8.8 U/mL) but the lowest in DPPH scavenging activity (12.2%). On the other hand, the extract of SK in 70% EtOH gave the highest TFC with 6485.3 mg QE/100g. The correlation of TFC and TPC with DPPH and T-AOC assays was positively significant. Conclusion: In conclusion, the ST extract yielded the best antioxidant capacity.


2018 ◽  
Vol 67 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Eva Ivanišová ◽  
Martin Košec ◽  
Ján Brindza ◽  
Olga Grygorieva ◽  
Marián Tokár

Summary The aims of the present study was to determine antioxidant activity, sensory properties as well as total polyphenol, flavonoid and chlorophyll content of raw and cooked pasta enriched by 1%, 3% and 5% addition of green barley powder. Results of antioxidant activity showed that increase of green barley addition increase antioxidant activity of pasta. The values in raw pasta obtained by DPPH ranged from 1.17 (control) to 1.81 (5% addition) mg TEAC/g DM, after cooking values ranged from 0.82 (control) to 1.59 (5% addition) mg TEAC/g DM. Similar tendency was signed by molybdenum reducing antioxidant power method. In enriched pasta was also found higher content of total polyphenol (0.19 in control raw sample and 1.81 mg GAE/g DM in pasta with 5 % of green barley addition; values of cooked pasta ranged from 0.10 in control sample to 0.73 mg GAE/g DM in pasta with 5 % of green barley addition) as well as total flavonoid content (results of raw pasta were from 0.00 in control sample to 0.41 mg QE/g DM in pasta with 5% of green barley addition; values of cooked pasta were from 0.00 in control sample to 0.29 mg QE/g DM in variant with 5% green barley). Green barley also enriched pasta for chlorophyll with the best results in 5% addition. From prepared variants of enriched pasta the best overall acceptability was sign in 3% of green barley addition. Pastas enriched with plant-derived bioactive compounds such as green barley may confer health benefits to consumers.


Author(s):  
Lani Irvin ◽  
Yarelia Zavala Ortiz ◽  
Kamila Rivera Rivera ◽  
Brajesh Nanda Vaidya ◽  
Samantha H Sherman ◽  
...  

We report the development of in vitro propagation protocols through adventitious shoot induction pathway for a rare and medicinal Scutellaria havanensis. In vitro propagation studies using nodal explants showed MS medium supplemented with 10µM 6-Benzylaminopurine induced highest number of adventitious shoots in a time dependent manner. A ten - day incubation was optimum for shoot bud induction as longer exposures resulted in hyperhydricity of the explants and shoots induced. We also report preliminary evidence of Agrobacterium tumefaciens EHA105 - mediated gene transfer transiently expressing of green fluorescent protein in this species. Transformation studies exhibited amenability of various explant tissues, internode being the most receptive. As the plant has medicinal value, research was carried out to evaluate its potential antioxidant capacity and the efficacy of methanolic leaf extracts in curbing the viability of human colorectal cancer cell line HCT116. Comparative total polyphenol, and flavonoid content measurement of fresh and air dried leaf extract revealed that the fresh leaf extracts contain higher total polyphenol and flavonoid content. The HCT 116 cell viability assessed by colorimetric assay using a 3-(4, 5-dimethyl-thiazol-2-yl)-2, 5-diphenyltetrazolium bromide, showed a steady growth inhibition after 24 hours of incubation. Scanning Electron Microscopy of leaf surface revealed high density of glandular and non-glandular trichomes. This research provides basis for the conservation of this rare plant and future phytochemical screening and clinical research.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ahmad Mohammad Salamatullah ◽  
Khizar Hayat ◽  
Fohad Mabood Husain ◽  
Mohammed Asif Ahmed ◽  
Shaista Arzoo ◽  
...  

Coffee is an intricate mixture of thousands of chemical compounds that are accountable for its flavor and aroma. Roasting is a key step in the processing of coffee beans. This study assessed the effect of microwave roasting (MW) and extraction solvents (ES) on the total polyphenol content, total flavonoid content, and antioxidant activity of coffee beans. The untreated and microwave-roasted (MR) coffee beans showed a total polyphenol content of 40.40 and 35.15 mg GAE/gm DW, respectively, when methanol was used as the solvent for extraction. Similarly, for the untreated coffee beans, the methanol extracted coffee had a significantly ( p < 0.05 ) higher total flavonoid content (39.34 mg CE/g DW) as compared to ethanol (34.82 mg CE/g DW). The obtained IC50 for the untreated and microwave-roasted samples as extracted by methanol were 4.13 and 5.68 mg/mL, respectively, while the IC50 values of untreated and microwave-roasted samples extracted by ethanol were 4.59 and 6.24 mg/mL, respectively. Untreated coffee beans exhibited a higher reducing power (1.237) than that of the microwave-roasted ones (0.839) when extracted with methanol. Chlorogenic acid was the major (2.31–2.68%) phenolic compound found in all the coffee samples whether it was untreated or microwave-roasted. Vanillin demonstrated the lowest (0.118–0.166%) phenolic compound found in the coffee bean samples. These results might be helpful for obtaining the maximum health benefits from coffee.


2020 ◽  
Author(s):  
Mohammad Alam ◽  
Md. Shahrear Biozid ◽  
Md. Faruk ◽  
Md. Jainul Abeden ◽  
Khandoker Usran Ferdous ◽  
...  

Abstract Background: Nymphaea capensis is an aquatic flowering plant which is included in the family of Nymphaeaceae. Literature review on the plants of Nymphaeaceae family exhibited significant medicinal activities. Therefore, the objective of the present study is to evaluate possible anti-oxidant activity of crude methanol extract of N. capensis leaf.Method: In antioxidant study, methanolic plant extract was evaluated for 1,1-diphenyl,2-picrylhydrazyl (DPPH) and reducing power capacity. Moreover, total phenolic and total flavonoid content of plant extracts were determined and expressed in mg of gallic acid equivalent per gram of dry sample (mg GAE/g dry weight).Result: In the DPPH free radical scavenging assay, methanol extract showed concentration dependent inhibition of the free radicals. IC50 of Ascorbic acid was 14.84 µg/ml whereas N. capensis was 130.94 µg/ml. In case of reducing capacity, at conc. 62.5, 125, 250, 500, 1000 ug/ml, the absorbances of Ascorbic acid were 0.65, 1.12, 1.45, 1.78 and 1.89 respectively. In case of N. capensis, the absorbances were 0.46, 0.75, 1.04, 1.27 and 1.50 respectively. The extract displayed a concentration dependent increase in reducing power. In the case of total phenolic content, the methanol extract of N. capensis contained a considerable amount of phenolic contents which was 215±7 of GAE mg/g. In the case of total flavonoid content, methanol extract of N. capensis contained significant amount of flavonoid contents which was 184.75±6.78 of GAE mg/g.Conclusion: These results suggested that the methanol extract of N. capensis possess considerable anti-oxidant activity.


2015 ◽  
Vol 14 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Matthias Onyebuchi Agbo ◽  
Philip Felix Uzor ◽  
Uchenna Nneamaka Akazie Nneji ◽  
Chidozie Uzoma Eze Odurukwe ◽  
Uchenna Basilia Ogbatue ◽  
...  

Plant phenolics and flavonoids play a great role in scavenging free radicals in the body and act as antioxidants. Thus their determination is sometimes nedded. Total antioxidant capacity, total phenolic and flavonoid contents of the extracts of 10 medicinal plants (Lochnera rosea, Allamanda cathartica, Asplenium platyneuron, Euphorbia prostrate, Baphia nitida, Crotolaria retusa, Zapoteca portoricensis, Platycerium bifurcatum, Mussaenda afzelii and Craterosiphon scandens) from 7 botanical families growing in the tropical rainforest of Nigeria were included in this study. The total antioxidant capacity of the extracts was assessed by using the phosphomolybdate method. The phenolic content was determined by using Folin-Ciocalteau assay, while the total flavonoid was determined by the aluminium chloride colorimetric assay. The results obtained showed that the total antioxidant capacity for all the extracts were in the range of 0.888 ± 0.75 to 0.938 ± 0.00 mg EAA/g. The results showed that E. prostrate, P. bifurcatum and A. platyneuron were found to be the richest source of phenolic (97.77 ± 0.77, 87.62 ± 1.22 and 82.33 ± 0.30 mg GAE/g) while B. nitida and M. afzelii had the least total phenolic content (11.67 ± 0.09 and11.18 ± 0.30 mg GAE/g). The highest total flavonoid content was revealed in P. bifurcatum (648.67 ± 12.3 mg QE) while M. afzelii also had the least total flavonoid content (3.67 ± 0.00 mg QE/g). The ratio of flavonoid to the phenolic in each extract was also determined to ascertain extracts that are rich in flavonoids.Dhaka Univ. J. Pharm. Sci. 14(1): 35-41, 2015 (June)


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