[Changes in the lysine of spiruline algae samples after various heat treatments].

The spirulina algae are microorganisms which are cultivated on Mexican lakes for feeding use. After drying, they contain about 52 per cent of proteins, with 4 per cent of lysine and 1, 7 per cent of methionine. In the studied samples, pH is 6, 2; they are partially autolysed and contain 4 to 18 per cent of free lysine and methionine and 6, 5 per cent of soluble carbohydrates. During heating treatments, the spiurlina lysine reacts as the same as oilcak meal lysine; it resists rather well to autoclaving but less to roasting. The yeast lysine is more stable than the spirulina lysine. The thermic stability of spirulina lysine is caused first by the small amount of free reducing carbohydrates, and for a minor part by the natural acicity of these products. The lysine destruction is proportional to the autolysis stage of the samples, that is to say the presence of free aminoacids. All the behavior differences between the various spirulina samples disappear when are heated with xylose, which induces a strong Maillard reaction.