Cell wall metabolism and cellular structure synergistically regulate texture in jujube fruit: implications for quality classification and processing adaptability.

Texture determines the commercial value and processing suitability of jujube fruits. In this study, we analyzed the dynamic changes in textural characteristics, cell wall materials, and cell wall metabolic enzymes during the development of three textural types (soft-, crisp-, and hard-fleshed) of jujube fruits (50-110 days after full bloom, DAFB), combined with cellular structure observations. The results identified 80-90 DAFB as a critical window for texture differentiation. Hard-fleshed fruits exhibited higher hardness, gumminess, chewiness, with elevated levels of ionic- and chelator-soluble pectins and cellulose, and small, tightly packed cells. Soft-fleshed fruits had large cellular cavities (3479.56-5960.56 μm2), while crisp-fleshed ones showed enlarged cells (2766.48-3908.73 μm2) with partial collapse. Polygalacturonase and β-galactosidase activities were strongly correlated with textural characteristics in type-specific patterns, and principal component analysis confirmed hardness, gumminess, and chewiness as reliable discriminators. These findings provide a biochemical and structural basis for quality classification and processing adaptability.