Moisture and Total Solids Analysis

Abstract

Moisture assays can be one of the most important analyses performed on a food product and yet one of the most difficult from which to obtain accurate and precise data, for reasons described in this chapter. The first sections of this chapter describe both direct and indirect methods for moisture content analysis: instrumentation, principles, procedures, applications, cautions, advantages, and disadvantages. The choice of moisture analysis method is often determined by the expected moisture content, nature of other food constituents (e.g., highly volatile, heat sensitive), equipment available, speed necessary, accuracy and precision required, and intended purpose (e.g., regulatory or in-plant quality control). Latter parts of this chapter describe water activity measurement, since it parallels the measurement of total moisture as an important stability and quality factor. Determining both the water content and the water activity of a food provides a complete moisture analysis. Also included in the chapter is a major section on moisture sorption isotherms. With an understanding of the techniques described in this chapter, one can apply appropriate moisture analyses to a wide variety of food products.