Extraction and characterisation of pomace pectin from gold kiwifruit (Actinidia chinensis)

Gold kiwifruit pomace extracted using citric acid, water and enzyme (Celluclast 1.5L) were studied in terms of pectin yield, protein, ash, non-starch polysaccharide, galacturonic acid (GalA), neutral sugar composition, molar mass (Mw), viscosity and degree of branching. Water-extracted pectin was considered closest to its native form. Enzyme extracted pectin showed the highest yield (∼4.5% w/w) as compared with the acid and water extraction methods (∼3.6–3.8% w/w). Pectin obtained from different extraction methods showed different degree of branching. The Mw and root mean square (RMS) radius varied with the extraction methods with values of 8.4 × 10⁵ g/mol and 92 nm, 8.5 × 10⁵ g/mol and 102 nm, 6.7 × 105 g/mol and 52 nm for acid, water and enzymatic extraction methods, respectively. Similar trend was observed for pectin viscosity, with water-extracted pectin giving a slightly higher viscosity followed by acid and enzyme-extracted pectin. This study showed that gold kiwifruit pomace pectin has potential application in food products

Characterization of gold kiwifruit pectin from fruit of different maturities and extraction methods

Studies on gold kiwifruit pectins are limited. In this work, the characterization of pectin isolated from two different stages of maturity of gold kiwifruit, namely early harvested fruit (EHF) and main harvested fruit (MHF) isolated by three methods (acid, water, enzymatic) was carried out. Pectins isolated from MHF were higher in galacturonic acid content (52–59% w/w) and weight-average molecular weights (Mw, 1.7–3.8 × 10⁶ g/mol) compared with EHF pectins (29–49% w/w and 0.2–1.7 × 10⁶ g/mol respectively). Enzymatic treatment gave the highest yield but lowest in Mw, viscosity and mechanical spectra for both maturities. The pectin of both maturities was classified as high-methoxyl pectin with the degree of esterification ranged from 82% to 90%. Water-extracted MHF pectin molecules had the highest RMS radius (182.7 nm) and Mw (3.75 × 10⁶ g/mol). The water extraction method appeared to retain the native state of pectin molecules compared with acid and enzymatic extraction methods based on the Mw and viscosity data