Mechanical properties of softened foodstuffs processed by freeze-thaw infusion of macerating enzyme

Mechanical properties of the softened foodstuffs were analyzed for the evaluation of care foods. The softened foodstuffs were prepared by a rapid impregnation of macerating enzymes using freeze-thaw infusion (FI) technique. FI technique using macerating enzymes has been able to soften foodstuffs, while retaining their original shapes. In this study, five foodstuffs (bamboo shoot, burdock root, lotus rhizome, Pacific cod, and shiitake mushroom) were tested. Their firmness, adhesiveness, and cohesiveness were analyzed by texture profiling analysis (TPA). Each firmness was decreased smaller than 1/10 of untreated samples. The adhesiveness of the Pacific cod was 70 times higher than that of the shiitake mushroom. As another mechanical property, fibrous texture was evaluated by the residual weight on the nylon mesh with 1 mm aperture. While the lotus rhizome exhibited the maximum weight of dried residue per sample weight of 1.26 × 10^{- 2} g/g, the value for the bamboo shoot was not detected. Industrial relevance: Advanced quality of commercial care foods is an increasing demand in the aging society. FI technique with some macerating enzymes can soften foodstuffs retaining their original shapes. Therefore, FI technique attracts much attention as one of the promising methods to manufacture universally designed foods. To achieve the product development of foodstuffs using FI technique, the information about their mechanical properties is required. It can be also utilized for consumers to estimate the textural safety on purchase. The results from this study will contribute to provide information for judgment of the ease of eating of these softened foods.