ÉVALUATION DE DIVERS TRAITEMENTS TECHNOLOGIQUES DES CÉRÉALES I. CHOIX DES TRAITEMENTS ET ÉTUDE DE LEUR INFLUENCE SUR LA FRACTION GLUCIDIQUE DU BLÉ, DE L'ORGE ET DU MAÏS

Abstract

Homogenous lots of 3 cereals, wheat, barley and maize, were subjected to the following treatments: Pelleting in a die press (.vphi. 4.5 mm) after previous steaming at 60.degree. C. Popping for 50 s at 280.degree. C, Flaking after previous steaming at 130.degree. C and Extrusion, in a press, of a finely ground (.vphi. 2 mm) and remoistened product, the temperature of which reaches 120.degree. C at the outlet of the die. The composition of the treated cereals was only slightly changed, except the fat content of wheat and maize, which was reduced by the extrusion treatment. The soluble carbohydrate fraction was generally only a little enhanced by the technological treatments, but it exceeded 7% for the 3 flaked cereals. According to the .alpha.-amylase test, barley and wheat are very sensitive to industrial moist-heat treatments, but the reactions of maize are variable. Extrusion highly increased the initial amylolysis rate and the easily hydrolysable starch fraction for each cereal flaking gave a little lower values and popping as well as pelleting only slightly affected maize starch. The choice of a method depends on its estimated energy cost and its influence on the composition of the cereals (water content, state of the carbohydrate fraction) and on their biological efficiency for various animal species.