Extraction and quantification of polyphenols from kinnow ( Citrus reticulate L.) peel using ultrasound and maceration techniques

Abstract

An investigation was carried out to extract polyphenols from the peel of kinnow (Citrus reticulate L.) by maceration and ultrasound-assisted extraction (UAE) techniques. The antioxidant potential of these polyphenols was evaluated using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and superoxide radical scavenging assays; and their antimicrobial activity was assessed against bacterial strains Staphyloccoccus aureus, Bacillus cereus, and Salmonella typhimurium. The highest extraction yield was obtained through the solvent ethanol at 80% concentration level, whereas UAE was a more efficient technique and yielded comparatively higher polyphenol contents than maceration. Maximum polyphenols were extracted with 80% methanol [32.48 mg gallic acid equivalent (GAE)/g extract] using UAE, whereas minimum phenolics (8.64 mg GAE/g extract) were obtained with 80% ethyl acetate through the maceration technique. Elevated antioxidant activity of kinnow peel extracts was exhibited in three antioxidant assays, where 80% methanolic extracts showed the highest antioxidant activity (27.67±1.11mM/100 g for FRAP) and the highest scavenging activity, 72.83±0.65% and 64.80±0.91% for DPPH and superoxide anion radical assays, respectively. Strong correlations between total polyphenols and antioxidant activity were recorded. Eleven phenolic compounds-including five phenolic acids and six flavonoids-were identified and quantified by high performance liquid chromatography. Ferulic acid and hesperidin were the most abundant compounds whereas caffeic acid was the least abundant phenolic compound in kinnow peel extracts. Maximum inhibition zone was recorded against S. aureus (16.00±0.58 mm) whereas minimum inhibition zone was noted against S. typhimurium (9.00±1.16 mm). It was concluded that kinnow mandarin peels, being a potential source of phenolic compounds with antioxidant and antimicrobial properties, may be used as an ingredient for the preparation of functional foods.

In vitro evaluation of antioxidant, antineurodegenerative and antidiabetic activities of Ocimum basilicum L., Laurus nobilis L. leaves and Citrus reticulata Blanco peel extracts

“…Zhang et al (2018) have found that TFC for Chinese C. reticulata methanolic extracts ranged from 23.29 to 56.52 mg RE/g, which was evidently higher compared to our results (6.34-8.05 mg QE/g). Generally, literature data demonstrate that the TPC and TFC vary depending on the locality, season, applied solvent and the extraction procedure (Javanmardi et al, 2003;Kivrak et al, 2017;Muñiz-Márquez et al, 2014;Safdar et al, 2017). In our study ( Table 1) the statistical analysis showed that the sample origin had a significant influence on both TPC and TFC.…”

Food waste: a potential bioresource for extraction of nutraceuticals and bioactive compounds

“…They concluded that that 50% acetone yielded the highest content of polyphenols compared to methanol, ethanol, ethyl-acetate and hexane. Safdar et al (2016) extracted and quantified polyphenols from kinnow (Citrus reticulate L.) peel. Maximum polyphenols were extracted with 80% methanol (32.48 mg GAE/g extract) using ultrasound assisted extraction, whereas, minimum phenolics (8.64 mg GAE/g extract) were obtained with 80% ethyl acetate through the maceration technique.…”

Enzyme‐ and ultrasound‐assisted extractions of polyphenols from Citrus sinensis (cv. Malta) peel: A comparative study

“…Our results are in accordance with those in peel of sweet orange as reported by Wang et al (). Other studies have also reported similar effect of sample matrix, extraction method, and processing conditions on the individual phenolic release and their content (Safdar et al, ). In a study on UAE of polyphenolics from sweet orange peel, showed presence of naringin (70.30 mg/100 g wb) and hesperidin (205.20 mg/100 g wb), later being the predominant compound (Khan et al, ).…”