Texture assessment instrumentation

Beilken et al. [ 12] have applied a number of instrumental measuring methods to assess the mechanical strength of 12 different meat patties. In all, 20 different physical/chemical properties were measured. The products were tasted twice by 12 panellists divided over 4 sessions in which 6 products were evaluated for 9 textural attributes (rubberiness, chewiness, juiciness, etc.). Beilken etal. [12] subjected the two sets of data, viz. the instrumental data and the sensory data, to separate principal component analyses. The relation between the two data sets, mechanical measurements versus sensory attributes, was studied by their intercorrelations. Although useful information can be derived from such bivariate indicators, a truly multivariate regression analysis may give a simpler overall picture of the relation. 

BS 1134, Part 1 1988. Assessment of surface texture, Methods and instrumentation. 

Voisey, P.W. 1976. Engineering assessment and critique of instruments used for meat tenderness evaluation. J. Texture Studies 7 11-48. 

Clearly, it may be possible to define and accurately measure many aspects of the mechanical and rheological properties of foods, but to try and relate these measures to consumer perceptions of the texture of the foods, is fraught with difficulties. Conversely, it is possible to train human subjects to assess textural characteristics of foods in defined and consistent ways (training them to mimic an instrumental response), however this may be missing the diversity of perceptions of food texture experienced by normal consumers. 

There would be considerable advantage for both sensory scientists and the food industry in knowing what consumers are measuring in order to assess particular textural properties. Despite many real advances in the instrumental measurement of food texture, we are not significantly closer to understanding the sensory cues used in consumer assessment of texture. The mastication process is adjusted to the consistency of the food bolus in real time. From studies of this process is emerging a novel approach to characterisation of food texture. 

Kapsalis, J.G. and Moskowitz, H.R. (1978). Views on relating instrumental tests to sensory assessment of food texture. Applications to product development and improvement. J. Texture Studies 9, 371-393. 

Another area of research that could be profitably explored is the use of remote sensing instruments to measure surface temperatures of textile assemblies. Infrared thermovision cameras have been used to visualize temperature distributions over clothed and nude persons in order to study the transport of microorganisms by convective heat flow (112). A variety of less expensive radiometers and radiation pyrometers that are used to measure and automatically control the temperature of textiles during drying and texturing (113, llU, 115) could also assess the thermal behavior of apparel and clothing assemblies and thus elucidate their contribution to thermal comfort indoors. 

Sensations perceived in the mouth during mastication may vary between subjects, but their acceptability will certainly reflect cultural as well as physiological and psychological differences. Tests for sensory assessment of texture aim at understanding how the food feels in the mouth. They may be classified into those where consumers are constrained to record only their perception of in-mouth stimuli (e.g., trained panel assessment) in other words, they are asked to perform as an analytical instrument. Alternatively, consumers are asked to record their judgment against requirements of quality (e.g., preference testing) where perceptions are related to expectation. Sensory assessment of texture is described in many texts, for example, Kilcast (2004). 

Texture analyzers are also used to assess deformability of a fluid, using penetration force vs. depth profiles, etc. These instruments in addition to Brookfield and Haake viscometers are common QC metrics. Other methods include viscosity flow cups and bubble or falling ball viscometers, and several relevant standard test methods include ASTM D1200, DIN/ISO 2431, ASTM D5125, BS3900 Part A6, ASTM D1545, and ASTM D1725. 

British Standards Institution, Methods for assessment of surface texture, B.S. 1134, Part 1, Methods and instrumentation, 1988, Part 2, Guidance and general information, British Standards Institution, 1990. 

In Chapter 6 we consider instrumental effects, such as spectral resolution and signal-to-noise ratio, and discuss data from the terrestrial and the giant planets in a qualitative manner. In Chapter 7 we examine methods for interpreting spectroscopic and radiometric data produced by real instruments in terms of physical properties of atmospheres and surfaces. Emphasis is placed on the retrieval of thermal stmcture, gas composition and cloud properties of the atmospheres, and thermal properties and texture of surfaces. Limitations on the information content inherent in measured quantities are assessed. 

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