Effect of supercooling accompanying the freezing process on ice crystals and the quality of frozen strawberry tissue

Abstract

Degradation of agricultural product quality occurs hugely during the freezing process, since ice crystal formation with volume expansion and increased osmotic pressure between cell membranes damages their microstructure. Recently, it is studied a freezing accompanied supercooled state for the entire food product, which induces finer and more homogenous ice crystals and improved the quality of soy bean gels after thawing. In this study, texture, drip loss, and microstructural changes were measured in frozen-thawed strawberries prepared by freezing with supercooling. In addition, ice crystals were observed directly using synchrotron X-ray computed tomography in supercooled frozen strawberries. The results showed, although supercooled freezing has the potential to form finer ice crystals in strawberry tissues, the quality of frozen strawberries was not improved compared with conventional slow freezing. It assumed that a higher and momently ice nucleation caused by supercooling was promoted a drastic water migration and huge degradation on strawberry cells by osmotic pressure in the frozen strawberries.