Application of freeze-thaw enzyme impregnation to produce softened root vegetable foods for elderly consumers

The aims of this study were to determine the viability of using freeze-thaw infusion (FI) technology to produce a range of root vegetables using enzyme treatments with improved texture characteristics for elderly consumers with swallowing difficulties. We applied enzyme impregnation as a technology to soften the textures of root vegetables commonly consumed in Korea; balloon flower root (Platycodon grandiflorus), burdock root (Arctium lappa L.), carrot (Daucus carota L.), and lotus root (Nelumbo nucifera Gaertn) through the use of a texture analyzer after the FI of a commercial enzyme. Out of 15 commercial enzymes that were analyzed, three enzymes exhibited a marked softening effect on the tested carrots, burdock roots, balloon flower roots, and lotus roots. The hardness of the enzymes-treated food materials reached 1.4 × 10⁴  N/m² for carrots, 3.0 × 10⁴  N/m² for burdock roots, of 3.0 × 10⁴  N/m² for balloon flower roots, and 3.2 × 10⁴  N/m² for lotus roots without changing the original shapes of the samples. These findings confirmed the potential benefits of softening carrots, lotus roots burdock roots, and balloon flower roots and will contribute to the development of foods that can be easily eaten as part of a balanced diet by elderly adults with eating difficulties.