Texture improvement and deformation inhibition of hot air-dried apple cubes via osmotic pretreatment coupled with instant control pressure drop (DIC)

Abstract

To inhibit the shrinkage and deformation as well as improve texture properties of hot air (HA) dried apple cubes, osmotic pretreatment and/or instant control pressure drop (DIC) coupled with HA were investigated. Shrinkage and deformation of apple cubes with dimension of 1.5 cm at classic HA drying process of 80 °C were analyzed, when moisture content reduced to 0.60 g/g d.b., it showed significant deformation including cell and pore collapse. Only osmotic pretreatment or DIC combined with HA could not improve the appearance and texture properties of apple cubes at the same time. However, osmotic pretreatment and DIC combined with HA (MD/MCC + HA + DIC) could significantly increase crispness (57–64) and reduce hardness (138–145 N) of apple cubes, and inhibit the deformation by increasing the volume by 1.6 times compared with that of HA dried ones. MD/MCC + HA + DIC could be an emerging combined technology to obtain dried products with good appearance and texture properties.