Q. Characteristics of food texture?
Hardness: It is defined as the force necessary to affect a given deformation. When judged by human senses, it is the force required to penetrate a food with molar teeth. Solids and some semi-solids have this property. For example, Cream cheese is low in hardness and raw candy is very hard.
Cohesiveness: It derives from the strength of internal bonds holding the body of the substance together. Cohesiveness, being the primary characteristic includes - brittleness Chewiness and gumminess - as the secondary characteristics. What are these characteristics? Let us know. Brittleness is judged by the taster as the ease with which the food can be cracked, then shattered or crumbled. Chewiness can be defined as the resistance of a product to compression and shearing action of teeth or the energy needed to masticate a solid food and gumminess can be understood to include the resistance offered by food when teeth/tongue are withdrawn after first penetrating the food i.e. the energy required to disintegrate a semi-solid food prior to swallowing.
Viscosity: It is measured as the rate of flow per unit force. The resistance of liquids to flowing is readily observed and is usually conveniently measured. For example, in the mouth, it is sensed as 'body' or thickness by small variation of resistance against the sensitive touch receptors of lips, cheeks, palate and tongue.
Elasticity: It is defined as the rate at which a deformed material goes back to its original shape. Elasticity is difficult to measure independently of other parameters. It is a part of chewiness.
Adhesiveness: It is measured as the work necessary to overcome the attractive forces between surfaces of material and surfaces that contact it. In eating, this property is sensed between food surfaces and mouth/throat tissues. For example, oil allows little adhesion, while peanut butter much.
All these textural characteristics discussed above are the working basis for food researchers, quality control experts and engineers busy in developing instruments to measure texture.