Sequential extraction of flavonoids and pectin from yellow passion fruit rind using pressurized solvent or ultrasound

BACKGROUNDPassion fruit rind (PFR) represents 90% of the total fruit weight and is wasted during juice processing. Passion fruit rind is known to contain flavonoids and pectin. An alternative use for this fruit juice industrial residue is to obtain these compounds. This study aimed to verify the influence of pressurized solvent extraction (PSE) or ultrasound assisted extraction (UAE) of flavonoid and pectin in a sequential process. RESULTSThe PSE using ethanol at 60:40 (v/v) yielded a total polyphenol content of 4.67g GAE kg(-1) PFR, orientin-7-O-glucoside (1.57g kg(-1) PFR) and luteolin-6-C-glucoside (2.44g kg(-1) PFR). Pectin yield was 165g kg(-1) PFR, either in PSE or UAE. Pectin characterization indicates that the pectic structure has basically homogalacturonans and galacturonate followed by a galacturonic acid ester unit, with methylation degree of 70%. CONCLUSIONWith this study it can be concluded that mixtures of alcohols with water favor the extraction of bioactive compounds of passion fruit peel. Both PSE and UAE were effective in sequentially extracting flavonoids and pectin. The preferred solvent is ethanol due to its lower toxicity. (c) 2017 Society of Chemical Industry