CHAPTER 3 - EVALUATING FOOD BY OBJECTIVE METHODS

Abstract

Methods used by food scientists to evaluate food quality include objective and sensory methods. This chapter describes the objective methods that do not depend on the observations of an individual; these methods can be repeated using an instrument or a standard procedure. Instrumental or objective methods include a wide variety of tests. The advantages of these tests are many. They may offer a permanent record of results and invite confidence because they are reproducible and less subject to error than the sensory methods of evaluation. However, if results of objective and sensory methods do not correlate, then they may not be measuring the same component of quality and hence the chemical or physical method may not be useful for the study. The appearance of foods can be recorded by means of photography or, in some cases, photocopying. A preliminary acceptance or rejection of a food is based on the visual appearance, including the color. In addition, the measurement of the size of food material particles or structural components may be of interest in research and quality control. The objective measurement of texture is complex because it must reflect the action of the mouth in removing food from an eating utensil; the action of the tongue and jaws in moving the food; and the action of the teeth in cutting, tearing, shearing, grinding, and squeezing food.