Détermination rapide de l'extrait sec des fromages à l'aide d'un four à micro-ondesA. DASEN and R. GRAPPIN
I.N.R.A., Station Expérimentale Laitière - 39800 Poligny
Abstract - Rapid microwave oven determination of the dry matter content in cheese
An experiment was carried out to determine the repeatability and accuracy of the dry matter determination of cheese with the microwave oven instrument TMS Checker K 375 A (Anritsu Co. Japan).
Sixty one samples of various type of cheeses (fresh lactic cheese, soft cheese semi-hard and hard cheese) ranging from 19.9 % to 62.8 % dry matter, were analysed with the microwave oven (4 replicates) and with the reference drying oven method (2 replicates).
The coefficient of variation of repeatability is on an average 0.26 % for the microwave and varies from 0.28 % for high moisture content cheese to 0.10 % for low moisture content cheese, for the reference method.
The standard deviation of accuracy of the microwave oven, calculated from the algebraic mean differences between the two methods is 0.27 % dry matter content, indicating a 95 % confidence interval of ± 0.54 % for the estimated true value.
In a field experiment, it has been demonstrated that the TMS Checker is a useful tool for checking rapidly the variation of soft cheese moisture during drainage. The dry matter content can be estimated front a single microwave determination with an overall accuracy of ± 0.68 % dry matter for a 95 % confidence interval.
Key words: Microwave oven / Determination / Moisture / Cheese
Mots clés : Four à micro-ondes / Dosage / Extrait sec / Fromage