Texture testers

Obviously in each area, certain specific items of test equipment will be used, such as small extruders, paint rigs, Stevens texture testers and penetrometers, etc. However, here we are interested in those pieces of rheological equipment that we should also find. The following important features are generally measured in rheological studies for typical liquids listed above, with some specific examples ... 

The solid-like properties may be measured by non-destructive dynamic rheology analysis or by destructive methods using a Penetrometer, Jelly Tester, Instron instruments, or other types of texture analyzers. The latter methods are the most useful due to their simplicity and speed. Texture analysis of whippable emulsion must always be compared with the amount of air incorporated into the foam, which is known as percentage overrun and is calculated as follows ... 

Two aspects of texture were considered firmness of the intact segment and toughness of the carpellary membrane. Both were measured on stored segments with an Instron model 1011 Universal Tester (Instron Corp., Canton MA 02021) set on compression mode. Firmness was determined by crushing a pair of segments in an Ottowa Texture Measurement System to 3 mm final thickness. Crushed segments were then transferred to a Kramer Shear Cell and the force necessary to shear the membranes determined. 

Texture. Firmness of the kiwifruit was measured in a 10 x 10 mm peeled area on both cheeks. A U. C. Davis fruit pressure tester with a 0.794 cm plunger was used in the study. The average value of twelve determinations is reported. 

In order to characterize the adhesive properties of the blends we used mainly the instrumented probe test developed in our own laboratory [35]. While it is in principle identical to the type of probe tester presented by Zosel [36] and currently commercialized by Stable Microsystems under the name Texture Analyzer, our design has introduced some important differences, shown schematically in Fig. 22.7. We have added a 45° mirror and a video camera to be able to visualize the contact area through a transparent substrate, and a very stiff tripod to be able to adjust the parallelism between the adhesive film and the probe in order to maximize the contact area. Additionally, compared with the commercial instrument, the compliance of our probe tester is much lower, avoiding some of the interpretation problems associated with testing a stiff layer with a compliant... 

Fig. 13.3. Cod fish quality change during storage (according to Ludorff, 1973). Sensory evaluation in total 15 points are given, 5 for visual appearance and 10 for odor, taste and texture Q-value electric resistance of the fish tissue as recorded by a fish tester Q40 quality class S, Q = 30-40 A, Q = 20-30 B, Q20 C and worse TMAO-N trimethylamine oxide-N TVB-N total volatile base-N VRS volatile reducing substances, TMA-N trimethylamine-N...

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