Color and appearance, those nebulous aspects of food acceptability which are taken for granted by most consumers, are coming under increasingly severe scrutiny. For this reason, it is essential that an adequate knowledge base for measurement be available to those working in the field. This base must be grounded upon the fact that color is a sensory phenomenon, and its measurement must include the physical, psychological, and physiological aspects. That is, measurement must involve tristimulus colorimetry, whether obtained by spectrophotometric or colorimetric techniques. It is the object of this article to review the general area of tristimulus colorimetry along with the techniques required for measurement. It is essential to include a section on the manipulation of data as well, since colorimetric data is often misused. Further treatment will be given to object-light interactions and how these affect not only measurement but sample perception, since manipulation of the physical parameters of the sample can affect the total appearance and color. Instruments and their usage will be reviewed so that decisions may be made on the correct instrument for a particular measuring system. In addition, a section will be devoted to on-line color measurement which may facilitate continuous processes. A final section of this article will deal with some advances in data manipulation and the development of new scales for color measurement. Fundamental colorimetric theory is essential in this area for proper usage. It is the aim of this paper to integrate theory with application in order to facilitate optimization of both the color of food and its measurement.

pounds have been positively identified and 20 compounds tentatively identified. Most compounds have been found in foods or sugar-amine model systems with the exception of 2-methyloxazole, 2-ethylpyrrole, 2-ethyl-5-methyl-6,7-dihydro-5H-cyclopentapyrazine, 4,5-dimethyloxazole-2-carboxaldehyde, 5-methyl-5fi-cyclopentapyrazine, 2-ethyl-5H-cyclopentapyrazine, 2-ethyl-3-methyl-5,8-di-

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Frankfurters were produced at 12, 20 and 29% fat levels using beef fat or GO% substitution with peanut oil. Less emulsion stability, lower smokchousc yield and lower sensory juiciness scores were found as final fat content of beef frankfurters was lowered to 12%. Firmness, darkening of external color, and flavor intensity were enhanced in the low fat product. Frankfurters with 60% fat as peanut oil cxhihited comparable emulsion stability and sensory quality parameters with no rancid flavor development over a period of 6 weeks at 4°C. They wcrc as acccptahle to sensory panels as the 29% beef fat frankfurters. Substitution of 60% of the beef fat with peanut oil resulted in a product with significantly (P < 0.05) less cholesterol content.