Isolation and characterization of Pomelo pectin and preparation of pectin derived Ag nanoparticles

Abstract

In this work pectin was isolated from pomelo (Citrus maxima sp.) peels and Ag nanoparticles were prepared in aqueous medium using isolated pectin with AgNO3 which is the silver precursor. Chemical confirmatory tests were carried out to identify the characteristics of the isolated pectin. It was found that the isolated pectin which is free from starch, is a non-reducing sugar and mainly consist of glycosides having jelly properties. Qualitative tests were carried out to study the solubility of pectin in hot/cold water and hot/cold alkali. Equivalent weight, methoxyl content, anhydrouronic acid content and degree of esterification were determined by titrimetric methods. Low esterification degree (<36.8%) indicates that isolated pomelo pectin is a low methoxyl pectin. According PXRD analysis, pomelo pectin was found to be amorphous in nature. FTIR spectra of isolated pectin revealed the existence of functional groups such as alcohol, carbohydrate ring, unsaturated ester, carboxylic acid, aliphatic amine and alkyl halide. Color change to yellow was used as an indicator to the formation of silver nano particles. Pomelo pectin derived silver nanoparticles were confirmed by UV-vis spectroscopy and their morphologies were examined through TEM. Spherical like structures with dark cores were observed for the nanoparticles and the dark core corresponds to nanosilver. They exhibited mean diameters ranging from 2-4 nm.