Total solids determination in dairy products by microwave oven technique

Abstract

The microwave oven technique is a reliable rapid alternative to classical air-drying in an oven for the determination of the total solids content in high moisture content dairy products. Microwave oven drying has the advantage of a selective heating of water which, combined with the short drying time, results in less lactose hydration and browning. The reduction of weight loss caused by degradation results in improved repeatability and reproducibility. This allows use of this technique as a rapid near-line technique, performed by operational staff, for release of intermediate or final product. The measurement is fast with a time of analysis of less than 5 min. Today's instrumentation is user-friendly and sample preparation is generally straightforward. As for all total solids determinations, a representative sampling is required and sometimes the sample needs to be homogenized. In some high fat products, dilution helps to improve the penetration of the product into the sample pad and afterwards favours water release during the drying process.