The use of synthetic foods to optimise microwave-assisted digestion procedures

Major food constituents such as proteins, fats and carbohydrates are generally recognised as having a strong influence on the performance of acid sample digestion. Various Scheffe mixture experimental designs were used to detect the influence and the interactions between these constituents during the Kjeldahl nitrogen digestion using focused microwaves. Pure ingredients were mixed in different proportions in order to prepare 7 synthetic food samples covering a wide range of foods types. 3 hearing powers were applied and nitrogen recovery yields were recorded at different times. Two types of models were proposed to describe the data: one that explains the shape of the recovery profiles. the other that gives the response surfaces of the recovery yield as a function of digestion time. From these models precise guidelines to optimise the digestion program of a given food can be deduce.