Effects of High Pressure on the Textural and Sensory Properties of Minced Fish Meat Gels for the Dysphagia Diet

Abstract

A new product of minced fish meat with high pressurization was produced for individuals with difficulties in mastication and swallowing and for elderly people on a dysphagia diet. Minced fish meat was added to distilled water at ratios of 1:0.5, 1:1 and 1:1.5 by mixing with 1.5% NaCl. Half of the samples were modified by heating (H-gels) and half by high pressure at 400 MPa for 20 min (P-gels). The hardness of the H- and P-gels was 0.97 to 2.83 [×104 N/m2] and 2.25 to 10.03 [×104 N/m2], respectively. For SDS-PAGE analysis, low-molecular-weight proteins in the P-gel were released more easily than those in the H-gel by the difference in gel formation, which is related to the detection of α-actinin in the supernatant of pressurized actomyosin. The ultrastructural observations showed a regular filamentous network structure in the P-gel. For the sensory evaluation, the P-gels were determined to be more lustrous, juicier, more moderately elastic and smoother. These gels conformed to the criteria of Dietary Uses for Dyspahgic Patients and Japanese Dysphagia Diet 2013. High pressure treatment denatured the protein composition of the minced fish meat gel, which led to a clearer three-dimensional network structure. High pressure made it possible to form minced fish meat gels with a low salt concentration. Obtained minced fish meat gels were improved in textural properties by addition of water and under high pressure, which were different from the ones by traditional heating. Improvement in textural properties will raise the sensory evaluation for elderly and dysphagic people. It is expected that the pressurized gels will be practical for a dysphagia diet.