engleski

Influence of microwave-assisted extraction on polyphenols recovery from mandarin peel waste

With increasing of interest in green chemistry, a more attention is being devoted to findings environmentally-friendly extraction method, and one of such is microwave-assisted extraction, which significantly reduced the time of sample treatment with uses of low volume of solvents. In that connection this work presents application of microwave-assisted extraction as an innovative technique for isolation of polyphenols from mandarin peel waste. Effect of solvents (ethanol and acetone) and its volume fraction (25, 50 and 70 %, v/v), temperature (30, 50 and 80 °C) and time (3, 7, 11 and 22 min) of extraction were evaluated with regard to total phenols and flavonoids content. The results revealed that all samples contained 52.52 to 110.58 mg/g of phenols and 8.26 to 18.13 mg/g of flavonoids with variations due to different time, temperature and solvent. The recovery of phenols from almost all samples enhanced by using of ethanol and rising the temperature from 30 °C (52.52 - 64.17 mg/g ) to 50 °C (57.01 - 76.37) and 80 °C (63.99 - 93.58 mg/g). On the other hand, by using acetone the yield of phenols decreased from 50 °C (74.10 - 99.42 mg/g) to 80 °C (58.07 - 96.28 mg/g). Similar to phenols, the low mass fractions of flavonoids are obtained at temperature of 80 °C, particularly by using 25 % ethanol (6.40 - 9.60 mg/g) and acetone (4.13 - 8.90 mg/g) for 3, 7, 11 and 22 min. Although the various parameters were involved in microwave-assisted extraction of mandarin peel, it should be emphases that temperature of 50 °C, time of 7 and 11 min, and 50 and 70 % ethanol and acetone presented the optimal, as well as compromise conditions between phenols and flavonoids isolation. Since the polyphenols were isolated in great amounts with minimal expenditure of time, applying eco-friendly microwave-assisted extraction, this technique could be utilized in further polyphenols production from sustainable, low cost mandarin peel.

flavonoids ; mandarin peel waste ; microwave-assisted extraction ; phenols ; UV/Vis spectrophotometry

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