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Texture Measurement

Texture Measurement . Principles. Which test to use?. Many food texture measurement techniques are available Many are empirical. They are not based on a theoretical approach; rather, they have been tested and seem to correlate with a useful property. Classifications.

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Texture Measurement

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  1. Texture Measurement Principles

  2. Which test to use? • Many food texture measurement techniques are available • Many are empirical. They are not based on a theoretical approach; rather, they have been tested and seem to correlate with a useful property

  3. Classifications • Many food systems and texture measurements exist • Different classification schemes have been proposed

  4. 1. Type of Commodity Tested • Cereal, meat, fish, poultry, vegetables, fruit, dairy, beverages, juices, nuts, legumes, oilseeds, etc • Different industries have tended to develop their own unique methods for testing products

  5. Liquids Gels Fibrous foods Turgid cell clusters Unctuous foods Friable structures Glassy foods Gas-filled vesicles 2. Food Type (Matz, 1962)

  6. Food Type: (Amerine, 1965) • Liquids • Fruits and vegetables • Meats • Other foods

  7. Food Type: (Sone, 1972) • Liquid foods • Gel-like foods • Fibriform foods • Cellular-form foods • Edible oils and fats • Powdered foods

  8. 3. Type of Test Used

  9. OBJECTIVE TESTS • Well-defined, repeatable, physical interpretations • May or may not correlate with sensor texture • Tests at small deformations • Mastication involves combinations of compression, shearing, tension • Chewing involves transient temperatures • Mastication introduces saliva and enzymes • Sensory texture evaluation may involve a combination of sensory data

  10. However, perceived texture properties are rooted in objective properties of food • A thin beverage will have a small Newtonian viscosity • A viscoelastic solid with high ductility may be perceived as chewy • Objective tests may also provide information about molecular structure and effects of processing

  11. Fundamental Tests • Measure specific rheological properties Shear modulus Viscosity Poisson’s ratio Storage modulus Complex viscosity Loss modulus Shear rate dependency Creep Stress relaxation • As measured by viscometry, DMA, force/distance curves

  12. Empirical Tests • Measure properties that are hard to define, but correlate with sensory, quality, or processing parameters • Advantages • Correlate with texture parameter • Quick and easy • Inexpensive • Disadvantages • Poor defintion of property • Limited standards • Limited to particular commodities

  13. Imitative Tests • Mimic conditions uner which food is used • Texturometer, TPA simulate chewing • Farinograph imitates working of bread dough

  14. Objective Tests:Further Breakdown • Which variables are measured • Force • Distance • Time • Energy • Ratios of these

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