Characterization of pectic polysaccharides and apple juice properties for 13 apple varieties

The physicochemical properties of apple juice from 13 apple varieties were correlated with the structural features of isolated apple pectin populations. Mathematical models explaining these structural properties, revealed variations in pectins as present in alcohol insoluble solids (AIS), water-soluble solids (WSS), and chelating soluble solids (ChSS). Significant differences in turbidity (89.00-4129 NTU), particle size (59.75-218.01 μm in D[4, 3]), and titratable acid (0.13 to 0.90 %) were observed, while pH, total soluble solids, and ζ-potential showed less variation. Juice yield (54.85-63.35 %) was inversely correlated with AIS, WSS, and ChSS content. Juice ζ-potential was positively correlated with the degree of methyl-esterification, methyl-ester distribution patterns, and the side chain sugar ratios of WSS pectin fractions. Juice quality as represented by juice clarity, texture and stability was significantly influenced by the diverse structure's features like sugar composition, methyl-esterification level and distribution of endogenous pectin. A partial least squares (PLS) regression model effectively predicted juice properties based on pectin characteristics. These findings underscore the importance of pectin structure in determining apple juice quality and provide a valuable framework for the juice industry to enhance quality control and inform cultivar selection.