Cryoprotective effects of trehalose on the physicochemical and microstructural stability of frozen apple purée

Abstract

Freezing is a common preservation method for fruit-based products but often leads to quality degradation caused by ice crystal formation and structural damage. This study aimed to evaluate the cryoprotective effects of trehalose on the physicochemical and microstructural stability of apple purée during 30 days of frozen storage at −18 °C. Apple purée samples were prepared with trehalose at concentrations of 0 %, 1 %, and 5 % (w/w) to investigate its efficacy in reducing drip loss, preserving microstructure, and maintaining nutritional and textural quality. Key quality attributes assessed included drip loss, moisture retention, texture-related properties, and microstructure, in addition to evaluating ash content, pH, total soluble solids (TSS), total phenolic content (TPC), antioxidant capacity (DPPH), and color parameters. Results indicated that trehalose significantly mitigated drip loss, with the 5 % treatment achieving the lowest value (6.0 %) compared to the control (14.8 %), suggesting enhanced water-binding capacity and reduced ice crystal-induced cellular damage. Microscopic analysis revealed that trehalose-treated samples exhibited reduced structural collapse and preserved parenchymal integrity, which contributed to improved textural consistency post-thaw. Furthermore, samples with trehalose showed better retention of TPC, antioxidant activity, and color, highlighting trehalose's protective role against oxidative and thermal degradation. These findings underscore the potential of trehalose as a cryoprotective agent in frozen fruit systems, with direct implications for improving the quality of minimally processed fruit products through structural stabilization and moisture management.