A process to preserve valuable compounds and acquire essential oils from pomelo flavedo using a microwave irradiation treatment

A microwave pretreatment method was developed to preserve pectin, naringin, and limonin contents in pomelo flavedo to allow for longer storage times and subsequent extraction of pomelo essential oil. In terms of the essential oil, microwave pretreatment performed better than hydrodistillation with respect to extraction efficiency (1.88 ± 0.06% in 24 min versus 1.91 ± 0.08% in 240 min), oxygenation fraction (48.59 ± 1.32% versus 29.63 ± 1.02%), energy consumption (0.15 kW h versus 1.54 kW h), and environmental impact (123.20 g CO2 versus 1232 g CO2). Microwave-pretreated samples retained higher amounts of pectin, naringin, and limonin compared with non-pretreated samples. No obvious change in the degree of pectin esterification was observed. This study shows that the proposed process is a promising methodology for both preserving valuable compounds in pomelo flavedo during storage and acquiring essential oils.