The texture of food for infants and young children
Résumé
The weaning period is a transition from milk to family foods and is a critical phase for the development of food acceptance and eating habits of children. The texture of the complementary food introduced plays an important role in shaping preferences. It is known that early introduction of solid food and experience in difficult-to-chew textures could enhance later food acceptance. Texture acceptance follows the developmental sequence of oral functions and infants are more likely to accept texture they can manipulate in mouth. The development of these functions (mainly chewing) is thought to depend on the texture infants are exposed to. Infant refusing foods that require significant chewing may fall behind in their oral motor development as a result of lack of experience with chewing. Moreover hard, fibrous, non-softened foods are thought to be the only foods able to encourage enough mastication to allow growing of dental arches. WHO guidelines recommend to start weaning at 6 months and to gradually increase food consistency as infants get older. A critical window for introducing lumpy food is also suggested (not beyond 10 months) to avoid feeding difficulties later on. Presently, ready-to-eat foods are an important part of weaning foods in most of the developing and developed countries. These commercial preparations meet nutritional needs at different age groups. Nevertheless, there is limited information available on the texture of these commercial preparations. The objective of this study was to characterise the structural properties of baby foods and to describe how these properties change as children grow. We selected 7 fruit purees, 18 savoury baby-foods and 4 biscuits, representing products proposed on the French market for 4/6 months to 24 months old children by three main baby-food manufacturers. Pureed products were characterised by their flow behaviour. All samples exhibited shear-thinning behaviour. Thixotropic behaviours were observed for samples containing banana and biscuits only. Significant differences in apparent viscosity (50 s-1) were observed between recipes but they were not related to age-group. Savoury foods were vegetable purees (4-6 months) which included particles (mainly carrots and pasta) from 8 months onwards. Particles were weighted and their size was determined by image analysis. Particles represented 12 to 49 % of product total weight and measured between 3 to 20 mm. The quantity and the size of the particles increased with age, but large variations were observed between brands and between recipes. The hardness of these particles is under investigation using extrusion method. Finally, experiments are currently ongoing to determine the physical (density, humidity) and rheological (3-point bending test and compression tests after short immersion in water/ saliva) properties of the cereal products.