engleski

Ultrasound assisted extraction of polyphenols from laurel leaves

Polyphenols are secondary plant metabolites, extremely important due to their antioxidant activity. Among lot of functions, polyphenols could be also utilised as an anticorrosion substances, according to the new trends for application of eco-friendly compounds in protection of metallic materials, such as tinplate, tin free steel and aluminium, frequently used in food preserving industry. Therefore, this work presents determination of optimum conditions of ultrasound assisted extraction (UAE) for polyphenols recovery from dried laurel leaves, which will be used in further preparation of extracts for monitoring of theirs anticorrosive activity. The ultrasound assisted extraction was performed using follow conditions: time of 3, 6 and 9 min, amplitude of 60, 80 and 100 % and ethanol and acetone as solvents, with volume fractions of 30 and 70 %. For comparison purpose, the isolation of polyphenols is also performed by refluxing, as conventional extraction techniques, during 1.5 and 3 h. The all obtained extracts were evaluated in terms of colour, total phenols and total flavonoids content. The results revealed that among used UAE parameters, the time of 9 min, 100 % amplitude and 70 % (v/v) ethanol and acetone could be used as optimal parameters for further extraction of polyphenols as an edible and ecologically acceptable corrosion inhibitors.

eco-friendly ; anticorrosion substances ; laurel ; polyphenols ; ultrasound assisted extraction

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