Investigation of moisture sorption properties of food materials using saturated salt solution and humidity generating techniques.

摘要

Moisture sorption properties, such as water activity, moisture content, and isotherms, are useful for a variety of processing and product stability applications, such as prediction of moisture transfer, development of new products, determination of product stability and shelf-life, and process design and control. Moisture sorption isotherms are obtained by two main types of methods: the standard saturated salt solution method and the more recent humidity generating method represented by the Dynamic Vapor Sorption (DVS) instrument from Surface Measurement Systems Ltd.;Even though the saturated salt solution method has been a standard method for many years, four main issues have been identified as major disadvantages with employing saturated solutions in desiccators to conduct relative humidity studies. Although the drawbacks associated with the saturated salt solution method have, in large part, been overcome by the recent development of humidity generating instruments, little research has been published investigating the reliability and applications of these new instruments.;This research will investigate and document the experimental procedures (best practices) of the standard saturated salt solution method and these humidity generating instruments using Dynamic Vapor Sorption instrument as a representative instrument. Four mold inhibitor methods were investigated in an effort to overcome the mold growth problem associated with the standard saturated salt solution method. In addition, applications of the humidity generating method were investigated to study the temperature effect on crystalline sucrose isotherms, to investigate the moisture sorption behavior of amorphous sucrose and to calculate the diffusion coefficient of cornstarches from DVS obtained data.;Therefore, there are two overall objectives of this project: (A) Develop best practices for both the standard saturated salt solution method and the new automated water sorption instruments with the Dynamic Vapor Sorption instrument as a representative instrument for obtaining moisture sorption isotherms, and (B) Explore additional applications of humidity generating instruments with the Dynamic Vapor Sorption instrument as a representative instrument.