Supercritical Fluid and Conventional Extractions of High Value-Added Compounds from Pomegranate Peels Waste: Production, Quantification and Antimicrobial Activity of Bioactive Constituents

Abstract

This study is focused on different extractions (Cold Maceration (CM), Ultrasonic Extraction (UE), Soxhlet Extraction (SE) and Supercritical Fluid Extraction (SFE)) of bioactive compounds from pomegranate (Punica Granatum L.) fruit peels using methanol, ethanol, and acetone as solvents in conventional extractions and changing operating pressure (10, 15, 20, 25 MPa) in SFE, respectively. The extraction yields, total phenols (TP) and proanthocyanidins (PAC) contents, and antioxidant activity of different extracts are revealed. TP and PAC recovered by extracts ranged from 24.22 to 42.92 mg gallic acid equivalents (GAE)/g and 2.01 to 5.82 mg PAC/g, respectively. The antioxidant activity of extracts ranged from 84.70% to 94.35%. The phenolic compound identification and quantification in selective extracts was done using the LC-MS/MS method. The contents of different flavonoids and phenolic acids have been determined. SFE extract, obtained at 20 MPa, contained the highest content (11,561.84 μg/g) of analyzed total polyphenols, with predominant ellagic acid (7492.53 μg/g). For the first time, Microbial Growth Inhibition Rates (MGIRs) were determined at five different concentrations of pomegranate SFE extract against seven microorganisms. Minimal Inhibitory Concentration (MIC90) was determined as 2.7 mg/mL of SFE pomegranate peel extract in the case of five different Gram-negative and Gram-positive bacteria.

Extraction and characterization of polyphenols from fruits and vegetable waste through green extraction technologies with special reference to antioxidant profile

“…The higher yield of polyphenols with supercritical fluid extraction as compared with ultrasound and conventional methods in the current experiment is in line with the recent findings of Kupnik et al (2022) compared with the different extraction techniques for the recovery of polyphenols from fruit peel. They noticed higher polyphenolic contents in the samples extracted through supercritical fluid extraction followed by ultrasound added extraction and lest through the conventional process.…”

A Review on the Potential Bioactive Components in Fruits and Vegetable Wastes as Value-Added Products in the Food Industry

“…Naringenin was the most abundant flavonoid found, with a maximum level of 84.04 mg/kg DW in oleoresin extracted at 550 bar, followed by caffeic acid (26.60 mg/kg DW). Kupnik et al [ 66 ] extracted bioactive constituents from pomegranate peel waste by using a supercritical fluid extraction method. The LC-MS/MS approach was used to identify and quantify phenolic compounds in selected extracts.…”

Pomegranate Peel Phytochemistry, Pharmacological Properties, Methods of Extraction, and Its Application: A Comprehensive Review

“…It is well established that various polyphenolic compounds can work synergistically to inhibit the growth of microorganisms. These compounds function as anti-infectives by forming complexes with extracellular and soluble proteins found in microbial cell walls, which precipitate membrane proteins and inhibit enzymes such as glycosyl transferases, thereby disintegrating the microorganisms. , Salmonella and Gram-positive S. aureus are strongly inhibited by PPEs, which have a strong antimicrobial effect on all bacteria. This is based on prior studies that discovered high quantities of tannins in PPE, which are highly efficient against some strains of the bacterium Staphylococcus aureus …”

“…Pretreated plant material is subjected to various solvents, including water, ether, hexane, chloroform, benzene, methanol, acetonitrile, and ethanol, which capture the desired molecules: polyphenols. 68,46 The sample was placed in a thimble attached to a solventfilled round-bottom extraction flask and condenser of a Soxhlet apparatus, as shown in Figure 3E. 69 The reflux operation was repeated several times before extraction was complete.…”