A Novel and Environmentally Friendly Technique for Extracting Pectin from Black Carrot Pomace: Optimization of Microwave-Assisted High-Pressure CO2/H2O and Characterization of Pectin

Abstract

Pectin is a valuable polysaccharide used in the food industry as a gelling, stabilizing, and emulsifying agent. It is one of the main components found in fruits and vegetables; however, it is mostly disposed of as waste during their processing. This study aims to optimize the extraction conditions of pectin from black carrot pomace by microwave-assisted high-pressure CO₂/H₂O method. This novel technique is based on the use of a combination of microwave with pressurized CO₂ in water to increase extraction yield and produce high-quality pectin. The effects of temperature (95–130 °C), time (2–12 min), and liquid/solid ratio (15–30 ml/g) on pectin yield were examined by using RSM. Optimum conditions obtained for microwave-assisted high-pressure CO₂/H₂O extraction were 130 °C of temperature, 2.0 min of extraction time, and 22.5:1 ml/g of liquid-to-solid ratio, which yielded a pectin recovery of 28.4%. The use of microwave-assisted high-pressure CO₂/H₂O extraction technique allowed 45% higher pectin recovery and about 97% time saving compared to the conventional acid hydrolysis method using acidified water (0.1 N HCl) (yield 19.55% and time 90 min). Pectin extracted by microwave-assisted high-pressure CO₂/H₂O was found to possess better characteristics compared to conventionally extracted pectin in terms of composition and physical, chemical, emulsion, and flow properties.