Pectin composition of blueberry (Vaccinium spp.) cultivars with contrasting instrumental juiciness

This study investigated how variations in pectin composition and architecture contribute to juiciness differences among blueberry cultivars. Although juiciness is primarily influenced by cultivar genotype, environmental conditions such as growing location and season also contribute. Despite consistent levels of total pectin and cell wall residues across cultivars, juiciness variations were associated with differences in pectin structure, specifically the degree of linearity and branching of rhamnogalacturonan-I (RG-I) side chains. Less juicy cultivars exhibited higher pectin linearity and reduced levels of neutral sugars, indicating greater degradation of galactan and arabinan side chains during ripening, which compromises cell-to-cell adhesion and enhances juice retention. Conversely, juicier cultivars maintained more branched pectin structures, particularly in the water-extractable pectin (WEP) fraction, supporting greater cell rupture and juice release. The accumulation of non-pectolytic sugars such as glucose and mannose, likely from matrix glycans, also correlated with increased juiciness, suggesting weakened cell wall networks. These findings highlight the critical influence of pectin structure and cell wall composition in modulating blueberry texture and juiciness, offering valuable insights for cultivar selection and postharvest handling strategies.