High-quality pectin from cantaloupe waste: eco-friendly extraction process, optimization, characterization and bioactivity measurements.

Abstract

The rind from cantaloupe is an agricultural waste of cantaloupe industrial processing. The current study tried to (i) evaluate the potential use of cantaloupe rind as a pectin source, (ii) optimize the factors of microwave-assisted extraction process using Box-Behnken design, and (iii) characterize the isolated pectin using various physicochemical, structural, functional and bioactivity properties. Four variables of the extraction process were successfully optimized at a microwave power of 700 W, irradiation time of 112 s, pH value of 1.50 and liquid to solid (LS) value of 30 mL g-1 , with a yield of 181.4g kg-1 . The analysis indicated a high-methylated galacturonic acid-rich (703.4g kg-1 ) sample with an average molecular weight of 390.475 kDa. Also, the isolated pectin showed considerable functionality and antioxidant ability. The main functional groups, structural characteristics and crystallinity of samples were comparatively studied using Fourier transform infrared, nuclear magnetic resonance and X-ray diffraction spectroscopies. In comparison to commercial citrus pectin, isolated pectin showed a significantly higher value for most of the functional analysis such as oil holding capacity, emulsifying capacity, emulsion stability, DPPH• and ABTS•+ scavenging activity, and reducing power assay. In other analyses the isolated sample was close to the commercial one, indicating that cantaloupe rinds should be considered as a suitable additional resource for pectin production. © 2021 Society of Chemical Industry.