Materials and Methods
All testing was done using FTC’s TMS-Pro Food Texture Analyzer, fitted with a 25N Intelligent Load Cell (ILC). For this test, the DualExtrusion Cell was used. This cell consists of three sample cups, 5 different diameter plungers (1 for forward extrusion, 4 for backward extrusion), and 4 cup bottoms (3 with different size orifices for forward extrusion, 1 solid for backward extrusion). For this application, the back extrusion setup was used. This allows the product to flow up and around the plunger as it moves down in to the product, which allows evaluation of the cohesivene of the texture.
Each replication first involved allowing the product to equilibrate to room temperature (approximately 70°F). Once a consistent temperature was reached, 50 grams of product was scooped into the sample cups. Three samples were prepared at once, first the regular product and then the low fat product. The replications were performed as quickly as possible to avoid any variances that change in temperature could affect. For each replication, the plunger traveled to a position that was 10mm from the base of the sample cup at a speed of 250mm/min. After the down-stroke, the plunger moved at the same speed back to the original starting point. The work (area under the curve) was calculated for both the down-stroke and the up-stroke.
Based on these results, a significant difference between the two products can be observed using the described methodology. While we were able to show a significant difference in these two samples, perhaps the more valuable data to the producer would be to look at how closely the low-fat product reflects the texture of the regular product. Often times with a reduced fat product, the goal is to make it as much like the standard product as possible. An objective way to measure this is crucial in the process as one must be able to consistently measure something if there is any chance of controlling it. Armed with this new data, the processor can now make more informed decisions when it comes to their processing operating procedure as it affects the overall texture of the product.