Optimization of microwave‐assisted extraction of pectin from Dillenia indica fruit and its preliminary characterization

Differences in physicochemical properties of pectin extracted from pomelo peel with different extraction techniques

In order to obtain high yield pomelo peel pectin with better physicochemical properties, four pectin extraction methods, including hot acid extraction (HAE), microwave-assisted extraction (MAE), ultrasound-assisted extraction, and enzymatic assisted extraction (EAE) were compared. MAE led to the highest pectin yield (20.43%), and the lowest pectin recovery was found for EAE (11.94%). The physicochemical properties of pomelo peel pectin obtained by different methods were also significantly different. Pectin samples obtained by MAE had the highest methoxyl content (8.35%), galacturonic acid content (71.36%), and showed a higher apparent viscosity, thermal and emulsion stability. The pectin extracted by EAE showed the highest total phenolic content (12.86%) and lowest particle size (843.69 nm), showing higher DPPH and ABTS scavenging activities than other extract methods. The pectin extracted by HAE had the highest particle size (966.12 nm) and degree of esterification (55.67%). However, Fourier-transform infrared spectroscopy showed that no significant difference occurred among the different methods in the chemical structure of the extracted pectin. This study provides a theoretical basis for the industrial production of pomelo peel pectin.

Modeling the influence of extraction parameters on the yield and chemical characteristics of microwave extracted mango (Mangifera indica L.) peel pectin by response surface methodology

Extraction is considered to be a critical unit operation to recover bioactive compounds from the in-situ state of many plant-based food processing wastes. The characteristics of pectin were predicted to vary with the source of raw material, extraction and post-extraction conditions. The study was focused to investigate the optimal conditions for extracting mango peel pectin (MPP) with increased yield and quality by microwave-assisted extraction (MAE). Box Behnken experimental design was used to model the influence of extraction parameters (microwave power, pH, and time) on the responses (yield, esterification degree, equivalent weight, anhydrouronic acid, and methoxyl content of pectin). The predicted models were adequately fitted to the experimental data (p ≤ 0.001) for all the response variables. A higher yield of pectin with better quality was obtained with optimal conditions of microwave power 606 watts (W), extraction time 5.15 min, and pH 1.83. The MPP obtained is categorized as low-methoxyl pectin as the range for the degree of esterification (DE) at all possible treatment variations remained below 50%. The study revealed that mango peel was an effective alternative source of pectin which could be extracted by microwave method on large scale.

Kinetic, Thermodynamic, Physicochemical, and Economical Characterization of Pectin from Mangifera indica L. cv. Haden Residues

The effect of temperature (60, 70, 80, and 90 °C) and time (30, 45, 60, 75, and 90 min) on citric acid extraction of Haden mango (Mangifera indica L. cv. Haden) peel pectin was evaluated in the present study. In order to obtain a better understanding of both the extraction process and the characteristics of the pectin (obtained from an agro-industrial waste) for a future scaling process, the following characterizations were performed: (1) Kinetic, with the maximum extraction times and yields at all evaluated temperatures; (2) thermodynamic, obtaining activation energies, enthalpies, entropies, and Gibbs free energies for each stage of the process; (3) physicochemical (chemical analysis, monosaccharide composition, degree of esterification, galacturonic acid content, free acidity, Fourier-transform infrared spectroscopy, thermogravimetric and derivative thermogravimetric analyses); and (4) economical, of the pectin with the highest yield. The Haden mango peel pectin was found to be characterized by a high-esterified degree (81.81 ± 0.00%), regular galacturonic acid content (71.57 ± 1.26%), low protein (0.83 ± 0.05%) and high ash (3.53 ± 0.02%) content, low mean viscometric molecular weight (55.91 kDa), and high equivalent weight (3657.55 ± 8.41), which makes it potentially useful for food applications.