Effect of Compression Ratio
The effect of the compression strain was examined by reducing the gap size. A compression from 10 to 5 mm
gap was initially supposed to be a twofold elongation. A reduction to 2.5 mm was assumed to yield a fourfold elongation, to 1.25 mm to an eightfold elongation and to 0.625 mm to a 16 fold elongation. As the material showed compressibility,the observed elongation was approximately a quarter of the theoretically expected elongation. Nevertheless, a compression to a 0.625 mm gap is equivalent to a compression of 93.75% of its initial height. With increasing compression,the maximal normal force increased from 2.2 N with a 5 mm gap to 35 N with a 0.625 mm gap. The force required for compression increased exponentially with decreasing gapwidth; these results are consistent with results found by Abhyankaret al.(2014). The exponential increase is explained with the increasing surface area during compression. The strain is not linear due to the constant plunger speed and decreasing gap width.The calculated parameters from the linearization are summarized in Table 2. For increased compression(decrease in gap width), the SRdecreased. However, it has to be considered that the compression to gap heights of 2.5 and 5 mm did not induce enough deformation to allow the determination of a RTk (Table 2). Therefore, the negativek1value for 5 mm gap height should not be over-interpreted. Ak2value close to 1, as seen for our samples,indicates a soft to semisoft food product with high viscousproperties (Peleg and Normand 1983). The increasedk2values for the experiments with gap height of 5 mm indicates that for small compressions cheese curd behaves more elastic. Differences in the relaxation behavior with degree of compression, can be explained by the compression speed of 1 mm/s, as relaxation can already begin during compression(Masi 1988)