73G-13 |
Constant and variable crosshead speed instrumental tests for predicting cheese texture |
M. L. FINNEY, M. Gaud, and J. F. Meullenet. Food Science, University of Arkansas, 2650 N Young Avenue, Fayetteville, AR 72704 Texture of foodstuffs has long been recognized as a multi-dimensional sensory quality. Sensory and instrumental tests are often carried out simultaneously in order to obtain correlation between the two methods. However, instrumental tests are performed at cross head speeds that are not representative of first bite jaw velocities. Furthermore, the crosshead speeds are usually kept constant while first bite jaw closing speed is dependent upon the physical properties of the food. The objectives of this study were, (1) to evaluate the first bite loading rates of ten cheeses of various texture and (2) to compare the effectiveness of instrumental tests performed at constant and variable cross-head speeds for predicting the sensory perception of cheese texture. Ten cheeses were chosen from twenty-five prescreened commercial products according to their hardness as evaluated by a trained descriptive panel. Using a cybermouse, jaw motion was recorded for 4 subjects. Average biting velocities were then calculated. Instrumental measurements were performed with a Texture Analyzer (TA-XT2i, Texture Technologies, Scarsdale, NY) fitted with denture casts taken from the four subjects participating in this study. Instrumental tests were performed at a constant crosshead speed of 10mm/s as well as at crosshead speeds matching data obtained from jaw motion recordings. Multiple instrumental parameters were extracted from the force deformation curves and used to predict sensory springiness, hardness and cohesiveness using partial least squares regression. Overall, variable speed instrumental data predicted the perception of the sensory attributes studied better. Correlation coefficients for hardness ranged from 0.84 to 0.98 for the variable speed models and from 0.71 to 0.84 for the constant speed models. Similar results were observed for springiness and cohesiveness, even though correlations were lower. These results show that current practices (i.e., constant speed instrumental testing) may not be appropriate to obtain high correlations between instrumental and sensory data.
Session 73G, Sensory Evaluation
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