A study was conducted to find out the effect of citric acid on total monomeric anthocyanins and antioxidant activity of liquor made from unprocessed purple-leafed TRFK 306 Kenyan tea, brewed at various time/temperatur...A study was conducted to find out the effect of citric acid on total monomeric anthocyanins and antioxidant activity of liquor made from unprocessed purple-leafed TRFK 306 Kenyan tea, brewed at various time/temperature combinations. Most purple tea consumers usually brew the tea leaves then add some lemon juice before consuming it. Citric acid was used here to mimic the use of lemon juice. Documentation on the quality of such a brew is scanty and the effect of acid on its quality is equally scanty. The current study used brewing time/temperature combinations of 5, 10 and 15 minutes with 70°C and 92°C drinking water. Total monomeric anthocyanins were analysed using UV-1800 spectrophotometer (Shimadzu, Japan) while DDPH method was used to assay for antioxidant activity. Citric acid concentration of 0, 0.1% to 0.5% was used to check their effect on the brews with the highest total anthocyanins and antioxidant activity. The results showed that brewing temperature of 70°C had 9.5 mg/L to 27.7 mg/L, with 5 minutes brewing time being the highest. Temperature of 92°C had 37.5 mg/L to 92 mg/L with 5 minutes brewing time having the highest total monomeric anthocyanins. Antioxidant activity of 92°C brewing temperature ranged from 90.7% to 92.0%. Total monomeric anthocyanins increased with increased citric acid concentration up to 0.3% before it decreases while for antioxidant activity, it decreased with addition of citric acid. It was concluded that for maximum anthocyanins extraction, 5 minutes brewing time is the best while ten minutes brewing time could give optimum antioxidant activity.展开更多
Phenolic compounds are naturally extracted molecules used nowadays for several industrial applications such as food preservatives and neutraciticals;thus industrial needs are in constant growth. Optimization of phenol...Phenolic compounds are naturally extracted molecules used nowadays for several industrial applications such as food preservatives and neutraciticals;thus industrial needs are in constant growth. Optimization of phenolic compounds (PC) and monomeric anthocyanins (MA) extraction from grape berries using response surface methodology was here achieved. Cabernet Sauvignon (CS) wine grapes (Vitis vinifera L. cv. Cabernet Sauvignon) are a rich source of anti-radical phe- nols, extractable as dietary supplements. However, efficiency of extraction strongly depends on specific experimental conditions. In this work, the comparison between two extraction mixtures, Acetone/Water (A/W) and Methanol/Water (M/W) and the effects of three critical variables—Extraction Time (between 8 and 88 h), Extraction Temperature (between 1?C and 35?C) and Solvent Content (between 63% and 97%)—on Phenolic Compounds Yield (PCY) and Monomeric Anthocyanins Yield (MAY) were studied using Response Surface Methodology (RSM). Process conditions maximizing the PCY were found to be 87% A/W solvent content, after 88 h incubation at 26?C, and those of the MAY were found to be 97% M/W solvent content, after 8 h incubation at 1?C. In addition, chromatographic profiles of extracts showed very different affinities of the phenolic compounds families to the experimental conditions employed. This process advantages are: low percentage of organic solvent used, high quality of extracted molecules thanks to low temperature treatment, very low energy consumption and low cost of needed machinery. At industrial scale, it may be used as promising technique for the extraction of bioactive compounds from plant or byproduct material such as from wine or grape juice industries.展开更多
In this work, optimization of phenolic compounds (PC) and monomeric anthocyanins (MA) extraction from Syrah (Sy) wine grapes (Vitis vinifera L. cv. Syrah) using response surface methodology was conducted. The comparis...In this work, optimization of phenolic compounds (PC) and monomeric anthocyanins (MA) extraction from Syrah (Sy) wine grapes (Vitis vinifera L. cv. Syrah) using response surface methodology was conducted. The comparisons between two extraction mixtures, Acetone/Water (A/W) as well as Methanol/Water (M/W) and the effects of three critical variables, Extraction Time (between 8 and 88 h), Extraction Temperature (between 1℃ and 35℃) and Solvent Content (between 63% and 97%), on Phenolic Compounds Yield (PCY), Monomeric Anthocyanins Yield (MAY) and the DPPH Free Radical Inhibition Potential (DFRIP) were studied. The highest PCY was obtained in 63% A/W solvent content after 88 h incubation at 35℃. The highest MAY was acquired in 97% M/W solvent content after 8 h incubation at 17℃. The highest DFRIP of the extract was attained using 97% A/W solvent content after 16 h incubation at 35℃. The low cost of this process, on economic and environmental levels, could lead to interesting applications on an industrial scale. It could be used to obtain bioactive phytochemicals from direct material or byproducts for either therapeutic or nutritional purposes.展开更多
文摘A study was conducted to find out the effect of citric acid on total monomeric anthocyanins and antioxidant activity of liquor made from unprocessed purple-leafed TRFK 306 Kenyan tea, brewed at various time/temperature combinations. Most purple tea consumers usually brew the tea leaves then add some lemon juice before consuming it. Citric acid was used here to mimic the use of lemon juice. Documentation on the quality of such a brew is scanty and the effect of acid on its quality is equally scanty. The current study used brewing time/temperature combinations of 5, 10 and 15 minutes with 70°C and 92°C drinking water. Total monomeric anthocyanins were analysed using UV-1800 spectrophotometer (Shimadzu, Japan) while DDPH method was used to assay for antioxidant activity. Citric acid concentration of 0, 0.1% to 0.5% was used to check their effect on the brews with the highest total anthocyanins and antioxidant activity. The results showed that brewing temperature of 70°C had 9.5 mg/L to 27.7 mg/L, with 5 minutes brewing time being the highest. Temperature of 92°C had 37.5 mg/L to 92 mg/L with 5 minutes brewing time having the highest total monomeric anthocyanins. Antioxidant activity of 92°C brewing temperature ranged from 90.7% to 92.0%. Total monomeric anthocyanins increased with increased citric acid concentration up to 0.3% before it decreases while for antioxidant activity, it decreased with addition of citric acid. It was concluded that for maximum anthocyanins extraction, 5 minutes brewing time is the best while ten minutes brewing time could give optimum antioxidant activity.
文摘Phenolic compounds are naturally extracted molecules used nowadays for several industrial applications such as food preservatives and neutraciticals;thus industrial needs are in constant growth. Optimization of phenolic compounds (PC) and monomeric anthocyanins (MA) extraction from grape berries using response surface methodology was here achieved. Cabernet Sauvignon (CS) wine grapes (Vitis vinifera L. cv. Cabernet Sauvignon) are a rich source of anti-radical phe- nols, extractable as dietary supplements. However, efficiency of extraction strongly depends on specific experimental conditions. In this work, the comparison between two extraction mixtures, Acetone/Water (A/W) and Methanol/Water (M/W) and the effects of three critical variables—Extraction Time (between 8 and 88 h), Extraction Temperature (between 1?C and 35?C) and Solvent Content (between 63% and 97%)—on Phenolic Compounds Yield (PCY) and Monomeric Anthocyanins Yield (MAY) were studied using Response Surface Methodology (RSM). Process conditions maximizing the PCY were found to be 87% A/W solvent content, after 88 h incubation at 26?C, and those of the MAY were found to be 97% M/W solvent content, after 8 h incubation at 1?C. In addition, chromatographic profiles of extracts showed very different affinities of the phenolic compounds families to the experimental conditions employed. This process advantages are: low percentage of organic solvent used, high quality of extracted molecules thanks to low temperature treatment, very low energy consumption and low cost of needed machinery. At industrial scale, it may be used as promising technique for the extraction of bioactive compounds from plant or byproduct material such as from wine or grape juice industries.
文摘In this work, optimization of phenolic compounds (PC) and monomeric anthocyanins (MA) extraction from Syrah (Sy) wine grapes (Vitis vinifera L. cv. Syrah) using response surface methodology was conducted. The comparisons between two extraction mixtures, Acetone/Water (A/W) as well as Methanol/Water (M/W) and the effects of three critical variables, Extraction Time (between 8 and 88 h), Extraction Temperature (between 1℃ and 35℃) and Solvent Content (between 63% and 97%), on Phenolic Compounds Yield (PCY), Monomeric Anthocyanins Yield (MAY) and the DPPH Free Radical Inhibition Potential (DFRIP) were studied. The highest PCY was obtained in 63% A/W solvent content after 88 h incubation at 35℃. The highest MAY was acquired in 97% M/W solvent content after 8 h incubation at 17℃. The highest DFRIP of the extract was attained using 97% A/W solvent content after 16 h incubation at 35℃. The low cost of this process, on economic and environmental levels, could lead to interesting applications on an industrial scale. It could be used to obtain bioactive phytochemicals from direct material or byproducts for either therapeutic or nutritional purposes.
