Cone penetrometers

De Man (1983) has reviewed this property of fats. Consistency is defined as (1) an ill-defined and subjectively assessable characteristic of a material that depends on the complex stress-flow relation or as (2) the property by which a material resists change of shape. Spreadabil-ity, a term used in relation to consistency, is the force required to spread the fat with a knife. The definition is similar to that for hardness the resistance of the surface of a body to deformation. The most widely used simple compression test in North America is the cone penetrometer method (AOCS Method Cc 16-60, 1960). More sophisticated rheological procedures are also available. Efforts have been made to calibrate instrumental tests with sensory response. With the cone penetrometer method, penetration depth is used as a measure of firmness. Hayakawa and De Man (1982) studied the hardness of fractions obtained by crystallization of milk fat. Hardness values obtained with a constant speed penetrometer reflected trends in their TG composition and solid fat content. 

TEXTURAL MEASUREMENTS USING A PUNCTURE PROBE OR A CONE PENETROMETER... 

Puncture probes and cone penetrometers provide a simple means for determining the textural properties of many structured foods (see sample results in Figure H2.2.1). 

Figure H2.2.1 Force/deformation curves illustrating three puncture probe tests (50 mm/min deformation rate) of an apple specimen and a cone penetrometer test (10 mm/min deformation rate) of Cheddar cheese, all at room temperature.

Puncture probes are commonly used for fruits and vegetables, and allow for the determination of force at rupture of the cellular structure. The procedure outlined below is adapted from the method of Bourne (1979). Cone penetrometers are commonly employed for determining firmness and yield value for foods such as margarine and butter, which may be a reflection of the product s spreadability. Quite often it is desirable to use a testing system that provides a constant deformation rate. Additionally, a mechanical testing machine allows for production of a force/deformation curve to further analyze the data. 

Cone Penetrometer (cone angle and geometry may vary)... 

The cone penetrometer was first developed for measuring the firmness or yield point of solid fats such as butter or margarine (Bourne, 1982). Assuming that the cone angle, mass of the cone assembly, temperature, and time for penetration are held constant, results from cone penetrometry can be interpreted based on the depth of penetration (Dixon and Parekh, 1979). Dixon and Parekh (1979) applied a cone penetrometer for measuring the firmness of butter. 

Tanaka, M., deMan, J., and Voisey, P.W. 1971. Measurement of textural properties of foods with a constant speed cone penetrometer. J. Texture Studies 2 306-315. 

Mortensen, B.K., Danmark, H. 1981. Firmness of butter measured with a cone penetrometer. Milchwissenschaft. 36, 393-395. 

Consistency of fats is commonly determined with the cone penetrometer, as specified in the Official and Tentative Methods of the American Oil Chemists Society (Method Cc 16-60). Other methods that have frequently been employed involve extrusion they include the extrusion attachment to the shear press (Vasic and deMan 1967), an extrusion rheometer used with the Instron universal testing machine (Scherr and Witt-nauer 1967), and the FIRA-NIRD extruder (Prentice 1954). 

Figure 8-32 Mechanical Model for Foods as Viscoplastic Materials. Source From M. Tanaka, et al., Measurement of Textural Properties of Foods with a Constant Speed Cone Penetrometer, J. Texture Studies, Vol. 2, pp. 301-315, 1971.

By toluene distillation for 2 hr or less. As a 5% solution in colorless mineral oil. By specified cone penetrometer test. 

Second Cone Penetrometer (conped). University of Wisconsin-Madison, Madison, Wisconsin... 

Mobile or submersible seabed systems can be subdivided into unmanned and manned systems (Figure 4.11). These systems typically have very limited penetration capability because of the lack of reaction in the free-swimming submersible. Even with the vertical thrusters on full power, forcing the submersible down to complement whatever negative buoyancy that can be provided, penetration of the types of equipment shown in Figure 4.6 has been about 1 m in hard soils and about 3 m in soft soils (Richards, 1972). In special studies, such as for pipelines, a carrier tool and test rod-sensor has been deployed from both unmaimed and manned submersibles. A cone penetrometer and a temperature cone have been deployed from both types of submersibles (Kolk and Power, 1983 Geise and Kolk, 1983). 

A typical stationary seabed system utilizing a stabilized drill string is the Wison wire-line cone penetrometer. 

The in situ testing equipment most commonly used to measure the strength of marine soils is listed in Table 4.3. In this table, the soil suitability for each probe is also estimated. Only three tools are in common use at present the vane, the cone penetrometer, and the piezocone. 

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