Phenolic Compounds Recovery from Pomegranate (Punica granatum L.) By-Products of Pressurized Liquid Extraction

This study aimed to valorize pomegranate by-products (peel and carpelar membranes—PPCM) through their high biological potential for phenolic compounds recovery. The influence of lower temperatures (40 and 60 °C) and pressures (20, 40, 60, 80, and 100 bar) than those generally used in pressurized liquid extraction (PLE) was evaluated through global extraction yield (X(0)), and qualitative and quantitative composition of the phenolic compounds. Chromatographic techniques were used to analyze the two treatments with the highest X(0). Temperature, pressure, and their interaction had a significant influence on X(0). The best phenolic compounds extraction conditions were using pressurized ethanol at 60 °C and 40 bar (extract 1—E1, 37% on d.b.) and 60 °C and 80 bar (extract 2—E2, 45% on d.b.). Nevertheless, E1 presented a significantly higher content of α, β punicalagin, and ellagic acid (48 ± 2, 146 ± 11, and 25.6 ± 0.3 mg/100 g, respectively) than E2 (40 ± 2, 126 ± 4, and 22.7 ± 0.3 mg/100 g). Therefore, this study could validate the use of low pressures and temperatures in PLE to recover phenolic compounds from pomegranate residues, making this process more competitive and sustainable for the pomegranate industry.