Texture objective measurements

Maturity. With the harvesting of the crop comes the first opportunity for application of objective measures of quality. The stage of maturity at which the crop is harvested is of great importance, for it is capable of having a marked effect upon the color, flavor, and texture of the finished product. 

In the study by Thompson, et al. (11), the ml of gel released per 100 g emulsion for the reference emuTsion without soy, with soy isolate (SIF), soy concentrate (SCF) or soy flour (SF) was 6.07, 5.83, 5.49 and 3.08, respectively, when the hydration ratios were 1 4 (flourrwater) for SIF, 1 3 for SCF and 1 2 for SF. The ml gel released per 100 g emulsion containing 10, 15, 20, and 25% soy protein was 6.70, 5.01, 3.94 and 3.57, respectively. When soy protein concentrate was incorporated into an emulsion at the 3.5% level, the processing yields, textural profile and sensory textural attributes of frankfurters were not different among the products with and without added soy concentrate (13). An objective measure of compression and shear modulus indicated that soy protein concentrate incorporated into frankfurters at the 3.5% level had no effect on batter strength or texture ( M). The addition of a cottonseed protein to frankfurters to replace 5, 10 or 15% of the meat resulted in higher pH, less cured color, less firmness of skin, softer texture and reduced desirability as judged by a sensory panel (J5J. 

Rheological studies of milk fat and butter are concerned mainly with objectively measuring spreadability and texture-related properties. Large... 

Notwithstanding all the limitations involved, the continuous improvement in precision and reproducibility of physical measurement equipment that relate to parameters perceived by human subjects make their use straightforward and they can provide consistent results. It is important to keep in mind that although instruments allow precise and objective measurements if applied to whole foods, they only can account for the initial structural properties contributing to texture perception. A correlative approach using sensory and instrumental techniques is often necessary. Indeed, there is no reason to determine accurately a mechanical property if it is not relevant to human sensory perception. Sensory methods become essential when calibrating instrumental equipment and are fundamental in product development, especially at early stages. 

Methods of objective measurement of cereal foam structures are reviewed, including image analysis, confocal microscopy and x-ray tomography. The analysis of foam structures and their relationship with mechanical and rheological properties is described, and also the relationships between these structures and sensory descriptors such as crispness, crunchiness and texture. The size, shape and anisotropy of bubbles and their cell walls in foams are seen as critical in determining their fracture properties and sensory perception of crispness. Techniques for measuring crispness using acoustic emission and force-deformation profiles are discussed. 

Reactions are taking place around you all the time. It is important tto be aware of your surroundings and understand how humans interact with these surroundings. Your five senses allow you to observe the world in which you live. In the lab, you only use four senses to make observations. Nothing is ever tasted in the lab. Sometimes tools can extend your senses. When you describe the color, odor, or texture of an object, you are making a qualitative observation. Quantitative observations involve measured quantities, such as 15 g or 2.5 L. It is important not to confuse observations and interpretations in the lab. Observations are made using your senses interpretations are proposed explanations that are based on observations. In this lab, you will be making both qualitative and quantitative observations. 

Texture is an important and complex quality characteristic. It is determined by variety and by structural and biochemical properties of tuber tissue, with some environmental influence. A considerable amount of research has been undertaken to replace subjective sensory evaluation with objective instrumental measurements (Van Dijk et al., 2002). 

Bourne, M.C. 1982. Principles of objective texture measurement. In Food Texture and Viscosity Concept and Measurement, pp. 114-117. Academic Press, San Diego. 

Moskowitz, H.R., Kapsalis, J.G., Cardello, A.V., Fishken, D., Mailer, O. and Segars, R.A. (1979). Determining relationships among objective, expert and consumer measures of texture. Food Tech. 33, 84-88. 

After segmentation, it is possible to measure the features of interest for each of the individuated objects. The measurable features regard size (area, perimeter, length, width), shape (circularity, eccentricity, compactness, extent, and so on), color, and texture (smoothness, coarseness, graininess) (Du and Sun, 2004). Texture, in particular, is evaluated on the base of the gray level variation within the object (Aguilera and Stanley, 1999). 

The most generalized property of a polysaccharide semisolid dispersion is texture, for which there are any number of definitions (Bourne, 1982), each nevertheless suggesting a physiological response to physical stimuli (size, shape, flow, hardness, etc.). Objectively, this elusive property is measured as the force necessary to compress or puncture the test object. 

Because most foods are complex disperse systems, there are great difficulties in establishing objective criteria for texture measurement. It is also difficult in many cases to relate results obtained by instrumental techniques of measurement to the type of response obtained by sensory panel tests. 

A variety of other words and expressions are used to describe textural characteristics, such as body, crisp, greasy, brittle, tender, juicy, mealy, flaky, crunchy, and so forth. Many of these terms have been discussed by Szczesniak (1963) and Sherman (1969) most have no objective physical meaning and cannot be expressed in units of measurement that are universally applicable. Kokini (1985) has attempted to relate some of these ill-defined terms to the physical properties involved in their evaluation. Through the... 

Voisey, P.W. 1970. Test cells for objective textural measurements. Can. Inst. Food Sci. Technol. J. 4 91-103. 

In this respect, the texture comprises all physical characteristics of foods related to the response to applied force and measured objectively in terms of force, distance, and time. Texture depends on the various constituents and structural elements of foods in which the microstructure components are formed and then clearly recognized in terms of flow and deformation during different processing treatments. 

A representative methane hydrate film position was selected for IR measurements by observing magnified images (160x) of the sample texture with a Cassegrainian mirror objective of 16x and an ocular of lOx. 

An appropriate combined use of molecular chemical information (NIR) and morphological measurements in macroscopic images (e.g., shape, optical texture, size) can enable the analysis of further complicated systems. This is particularly relevant when objects composed of different color-same compartments are being processed (e.g., meat slices), or when the product is composed of heterogeneous pieces within a bulk, such as animal feed. 

The space In the vicinity of the chosen point can be extended somewhat by using a series of overlapping techniques and thus defining movement In the space. The extension Is realized once spatial variations In composition are measured In space-time determining an object s "texture" and thus the object Is "characterized". The analyst essentially decides how to build an... 

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