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The effect texture has on food quality is enormous.
It could be used directly as a parameter to determine the food quality, such as a mushy apple from over-riping or crunchy potato from under-cooking.
Food texture is a discipline on its own in the field of Food Science & Technology.
This feed will be about how the food texture affect the quality of food as well as how it should be measured and interpreted.
1. Quality factor in food
Food Quality is determined based on the factors that influence the appeal to consumers.
- Nutrition: CHO, Protein, Fat, Vitamins, Minerals
- Appearance: color, shape, size (eyes)
- Flavor: taste (tongue), odor (nose)
- Texture: tactlie contact with some part of body and food
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2. What is food texture
- Definitions
- Composite of attributes sensed physiologically from structural elements
- Physical properties (size, shape, number, nature, structure) + sense of touch, sight, hearing
- Physiological-psychological perception of rheological and other properties of food
- Measurement
- Mechanical and rheological science is used to determine how solid or fluid the food is
- Texture used for measuring solid and viscosity for liquid
- The human perception may be different from empirical tests
3. Disciplines related to food texture
- Food rheology
- Other properties: wettability, phase changes, surface tension
- Psycophysics
- Psycorheology
- Mastication, Anatomy, Physiology, etc.
4. Importance to consumers
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- Importance level differs via food type
- Critical: meat, celery, chips
- Important: fruit, bread, candy
- Minor: beverages, thin soups
- More important with bland foods (chip, cereals, vegetables)
- Consumer perception on Texture
- Texture is taken for granted, so its defect can cause consumer complaints, more easily than flavor and appearnce.
- Texture consciousness: evaluated sub-consciously unlike flavor, appearance
- Perception influenced by age, culture, time of day (different language with different vocabularies or people preferring more variety of texture in the evening and softer texture in the morning)
- The texture is harder to control in food product compared to flavor where it can simply be added or removed
5. What is Rheology
- Rheology: how materials flow (fluid) or deform (solid) when subject to various forces
- Related to texture (mouthfeel, chewiness)
- Determines how to process food: amount of time to heat food, extrudability, pump size
- Texture changes due to processing
- Native food: original structure of agricultural commodity
- Formulated food: processed from diff ingredients, native structure is lost (Jelly, candy)
- e.g. Grinding flour to form a dough
- e.g. Fermenting milk to produce cheese
- e.g. Freezing ice cream to produce gelato
- e.g. Cutting chicken to produce nuggets
- Inadvertent and undesirable changes
- e.g. Frozen strawberries
- e.g. Mushy overcooked foods
6. Types of food
- Fluids: deforms continuously when acted on by shearing force
- Elastic solid: deforms by a finite amount when force applied, but returns to original form
- Semi-solid: acts both as liquid and solid
7. Sensory and physical measurement
Food texture is an addition of the food's physical properties and how it is percieved to consumers.
- Physical properties: mechanical instruments, quantitative, reproducible
- Rheology: physics describing physical/mechanical properties of food
- Young’s modulus, shear modulus, poisson’s ratio, viscosity, loss compliance
- Sensory properties: human perception as an instrument, Limited reproducibility, Different terminology
- Haptaesthesis: psychology describing perception of mechanical properties of food
- Mouthfeel, Hardness, Chewiness, Gumminess, Adhesiveness