Evaluating Food Texture

The crispiness of fried food is an extremely important quality in food development. For evaluations of food like this, a sample is to be set on the cylinder, and the test power is measured at the time of breakage when the sample is extruded by the ball extrusion jig.

Gelatin specified by JIS K 6503 can be tested. A glass container with the inside diameter of 60mm and the height of about 85mm and a compression plunger (columnar jig) with 0.5inch (12.7mm) are used. Set the infiltration rate at 1mm/sec and infiltration distance at 4mm, and measure the test power at that time.

This is a three-point bend jig where 80mm is the maximum width for a sample, and the maximum distance between fulcrums is 100mm. By measuring the bending strength of samples, the breaking strength and simple elastic modulus are measured, which provides the indices of the hardness and brittleness of the food products. It is used for evaluation tests for samples with relatively consistent inside structures, such as cookies and chocolate bars. The tip of punch and the tip of fulcrum can be selected from R0.1, R1, and R2.5.

This is a jig for tensile tests of noodles, such as udon, soba, and pasta. Tensile tests are useful for evaluations of the stickiness and stretchiness of noodles. It is important that noodles be caught firmly when fixed to the jig, not to be slipped off that part of the jig and not to be broken. Noodles can be fixed firmly around the jig with the aid of their own clamping power, which makes it lower possibility for the noodles to slip. By taking advantage of this self-clamping effect, damage to the noodles caused by the jig can be reduced, and breakage at the grip part can be prevented.

The hardness of breakfast cereal was measured with a special jig called Kramer shear cell. The hardness of the all flakes and crunchiness are evaluated by the inclination of the beginning of the test power and the jagged waveform made by the breakage of each flake.

Extrusion tests are used to evaluate the viscosity of samples and the hardness of the liquid. A sample in a cylinder container is compressed at a fixed speed, and a tubing test jig is used for measuring the test power when a sample is extruded out of small holes at the bottom of the cylinder container. Disks with extrusion hole diameters of 3, 5, 7, and 10mm can be changed according to the density and viscosity of the samples tested.