Co-optimization of pectin and polyphenols extraction from black mulberry pomace using an eco-friendly technique: Simultaneous recovery and characterization of products

Int J Biol Macromol. 2020 Jul 14;164:1025-1036. doi: 10.1016/j.ijbiomac.2020.07.107. Online ahead of print.

Abstract

The current work investigated a simultaneous recovery of pectin and polyphenols from black mulberry pomace (BMP) using an eco-friendly extraction process. The microwave-assisted extraction variables were successfully co-optimized using Box-Behnken design considering pectin and polyphenols yields as responses. The optimized condition yielded about 10.95% pectin and 12.11% phenolics. The physicochemical analysis indicated a highly-esterified pectin (DE of 62.21%) with an average molecular weight of 620.489 kDa and galacturonic acid (GalA) content of 70.15%. FTIR and NMR spectroscopies confirmed the predominant presence of highly esterified GalA-rich structure for BMP pectin. XRD analysis suggested an amorphous structure for the main part of BMP pectin. Also, DSC results showed higher thermal stability for BMP pectin in comparison to commercial pectin. Moreover, the antiradical activity of BMP phenolic extract was very close to that of butylated hydroxyanisole (BHA) and ascorbic acid. The results showed that the suggested procedure can be a promising solution for the management of BMP waste generated in juice, syrup, or liquor processing plants. Also, the quality of the obtained products (BMP pectin and BMP phenolic extract) indicated that the products have the potential to be used as natural ingredients in various food and pharmaceutical products.

Keywords: Black mulberry pomace; Pectin; Phenolic compounds.