The texture of plant products is largely influenced by the composition and condition of their cell walls, which consist of biopolymers such as cellulose, hemicellulose, and pectin. The turgor pressure, created by water within the cells, helps maintain crispness. If plants maintain both their cell structure and turgor during handling and storage, they remain crisp and fresh. In addition, these products may contain a high concentration of cell-wall biopolymers, which contribute to their texture.
As fruits ripen, however, a breakdown of the cell-wall polysaccharides occurs, often through enzymatic activity. Soft fruits like peaches and tomatoes experience a softening process attributed to pectinolytic enzymes, which degrade pectin in the cell walls. In some cases, like avocadoes, cellulose plays a more prominent role in the ripening process. This enzymatic breakdown leads to the desired tender texture in many ripe fruits.
Conversely, the accumulation of lignin, a phenolic-containing biopolymer, can cause an undesirable woody texture in certain products, such as asparagus. Lignin stiffens the cell walls, reducing tenderness. Moreover, the mushy texture associated with bruises results from the rupture of plant cells. When this happens, enzymes are released, which accelerate the degradation of cell-wall polysaccharides, primarily pectin, leading to a loss of structure and an unappealing mushy consistency.
Understanding Plant Texture: Factors Affecting Crispness, Softness, and Ripening
