Bio-extraction of polyphenols from Lemon peels using ultrasound assisted pretreatment

Abstract

The increasing interest in natural products for their health benefits has resulted into to the exploration of natural rich sources like fruits, vegetables among others. Polyphenols are well known for their health benefits and these are obtained from various natural sources with lemon peels as one of them. This project aimed at assessing the effect of ultrasound pretreatment on bio extraction of polyphenols from lemon peels. The effect of different extraction conditions on polyphenol yield were assessed. Quantification of the total polyphenol content (TPC) was done using UV-Vis spectrophotometry and characterization using Fourier Transform Infrared FTIR. The optimum conditions for the highest total polyphenol content (6.05±0.82 mg GAE/ mg dry mass) were obtained by 1.5 hours of extraction time with ultrasound assisted pretreatment in 70% ethanol concentration at 20 kHz and 5g of lemon peels. This yield was higher than the total polyphenol content from conventional extraction (4.34±0.60 mg GAE/ mg dry mass). Ultrasound pretreatment interaction with ethanol concentration showed the most significant difference in the total polyphenol content (p<0.0001) while preserving the structure of hesperidin and eriocitrin as observed from the FTIR. Results of this study implied that ultrasound assisted pretreatment was better method for polyphenol extraction from lemon peels as compared to conventional extraction.