Measurement of food texture: human perspective vs material perspective

To fill the gap between the sensory evaluation and the instrumental measurement of texture, it is necessary to examine the physical change of foods during the oral processing. This will give us the designing principle of palatable and safe foods.

Some of the difficulties associated with any objective attempt at measuring food textures are discussed including the double role played by language as the vehicle for transforming subjective “knowing” of a texture into a form suitable for describing the effect to others. It is stressed that a satisfactory solution to the problem of objectivizing a texture measurement will require a multi‐disciplinary approach since psychology, physiology and rheology all interact when one senses texture during chewing. Therefore, to objectively measure a texture, the causal relations between these “… ologies” must first be established. The reviewer advances the idea that objective texture measuring activities fall into three distinct categories which roughly correspond to (1) What is the magnitude of the texture and how is it best measured? (2) From whence does it arise? and (3) How does one bring it into existence? The major works reviewed are considered in the light of this activity classification.

Pan bread formulations based on raw wheat germ, vital wheat gluten, and enzyme-active soybean flour were optimized with the objective of developing a phytochemical-enriched designer food product with superior nutritional and sensory qualities. The objective texture values (measured as compression force, g) indicated that the test bread with 10% wheat germ addition was comparable (299.9 g) to the control (210.1 g), but the compression force was significantly higher (415.4 g) at 20% wheat germ level. With 0.5% sodium stearoyl-2-lactylate (SSL), 30 ppm potassium bromate and 50 ppm ascorbic acid, the test breads with 10 and 20% wheat germ had compression force values of 313.8 g and 367.7 g, respectively. Comparing the CIE L*a* values, the test bread samples having up to 20% wheat germ were slightly darker in crumb color than the white flour control bread, but were significantly lighter than the whole wheat flour bread. However, the addition of wheat germ increased the yellow color of bread crumb as indicated by the higher b* values of 11.4, 16.4 and 21.4, for control, 10% and 20% wheat germ breads, respectively. The physical texture and objective color measurements can be used in evaluating the quality of a phytochemical-enriched designer food (pan bread). It can be concluded that wheat germ-enriched bread can be prepared by using white flour, 20% raw wheat germ, 0.5% SSL, 30 ppm potassium bromate and 50 ppm ascorbic acid to provide consumers with a functional food.

ABSTRACTThe present study reports on the classification of terms used to describe texture and/or mouthfeel characteristics of coffee, particularly espresso coffee, resorting to the classical food texture approach and putting in evidence how consumption habits (i.e., the brewing method) affect the terms used to describe it. Trained panelists have been interviewed in order to generate spontaneously a large number of descriptive texture terms. The terms collection was processed according to methodology previously adopted for liquid foods and beverages to classify the terms into well known mouthfeel categories. This classification identified a reduced number of texture terms categories to set up a list of terms submitted to the same trained panelists and to 93 Italian and 143 non‐Italian consumers in the form of a questionnaire with forced choice. Results show that the term “body” alone cannot be used to describe the mouthfeel of coffee beverages, prepared with different brewing methods. The obtained responses may constitute the basis for the development of an appropriate terminology for communicating the mouthfeel characteristics of espresso coffee, and may assist in addressing the finding of correlations between perceived texture and objective measurements of physical properties of the beverage.