D. Cisse et al., EFFECT OF FOOD-PROCESSING ON IRON AVAILABILITY OF AFRICAN PEARL-MILLET WEANING FOODS, International journal of food sciences and nutrition, 49(5), 1998, pp. 375-381
The effects of different cereal precooking process (roasting and extru
sion cooking) on iron availability and protein digestibility of four A
frican weaning foods were investigated using in vitro methods. In two
weaning foods based on pearl miller, cowpea and peanut, the cereal was
extruded (A) or roasted (B), In two other weaning foods having a simi
lar composition, a low proportion of milk powder was added and the cer
eal extruded (C) or roasted (D). The mean +/- SD iron values (mg/100 g
) were: A, 5.56 +/- 0.18; B, 9.12 +/- 0.93; C, 5.89 +/- 0.23; D, 9.04
+/- 0.85. When the pearl millet was roasted, the iron content was high
er than in the extruded weaning foods (P < 0.01). However, the percent
of available iron of the roasted weaning foods was very low (B, 1.64
+/- 0.01; D, 0.91 +/- 0.02). The iron availability of the extruded wea
ning foods, A and C, was 3.5 times and 6.5 times higher than the corre
sponding roasted weaning foods, B and D, respectively. This represente
d 332.4 +/- 4.4 and 375.1 +/-: 5.8 mu g of available iron/100 g for A
and C, respectively versus 149.5 +/- 0.9 and 82.2 +/- 1.8 mu g of avai
lable iron/100 g for B and D, respectively. No significant differences
in polyphenol contents were found according to the precooking process
of the cereal. The extruded weaning foods showed a higher protein dig
estibility of approximately 10% than the roasted ones (P < 0.05). A po
sitive correlation was found between in vitro iron availability and pr
otein digestibility (r = 0.976, P < 0.02). Despite a high content of i
ron, the iron availability of roasted pearl miller weaning foods was q
uite low. Extrusion cooking of the cereal improved the protein digesti
bility and iron availability of pearl miller weaning foods; however, t
he amount of available iron remained insufficient to meet the iron req
uirements of infants whatever the cereal processing.