Characterization and formation process analysis of peach fruit woolliness under low-temperature storage

Woolliness in peach fruit during low-temperature storage considerably reduces quality, primarily owing to the formation of pectin gel. This study systematically analysed texture, water distribution, cell wall microstructure, and pectin gel formation during peach storage. Peaches stored at 5 °C exhibited increased firmness, membrane permeability, and water binding capacity than those at 10 °C. These changes resulted in cell wall thickening and reduced extractable juice. Low-field nuclear magnetic resonance (LF-NMR) revealed an enhanced interaction between water and pectin. Rheological analysis indicated a transition from viscoelastic fluid to a solid/gel state after one week of storage, with a distinct gel structure forming after three weeks. Additionally, increased arabinose (Ara) and galacturonic acid (GalA) contents, including the retention of high molecular weight pectin and a low degree of esterification at 5 °C, were observed, which may have promoted gel formation. These findings provide new strategies for managing fruit woolliness under low-temperature conditions.