Effect of extrusion cooking and amylase addition to gruels to increase energy density and nutrient intakes by Vietnamese infants.

Extrusion cooking and amylase addition are two processing methods used for the preparation of high energy dense (ED) gruels of suitable consistency. A quantitative study of energy and nutrient intakes of 67 infants aged 6 to 10 months in rural areas in Vietnam was carried out to compare the effects of these processes used alone or in combination. Twice a day, for a period of four days each, infants successively ate four gruels prepared from different flours based on a blend of rice, sesame and soybean: an instant flour obtained by extrusion cooking (gruel A), a ready-to-cook flour obtained by extrusion cooking plus alpha-amylase addition (gruel B), a flour produced by milling crude rice, sesame and roasted soybean plus alpha-amylase addition (gruel C) and without amylase (control gruel D). Gruels A, B and C had a high ED of respectively 94, 122 and 124 kcal/100 g while the control gruel D had a low ED (59 kcal/100 g). The intakes of the four gruels were inversely linked to their ED. However, despite the fact that gruels B and C had similar ED, larger intakes were obtained with gruel B, which was attributed to better acceptability. The average energy intakes of high ED gruels A, B and C, respectively 112, 134 and 117 kcal/meal, were significantly higher than that of gruel D (81 kcal/meal). Of the three processing methods, the one combining extrusion cooking and amylase addition gave the best results in terms of gruel acceptability and energy intake.