Extruded Flaxseed Meal Enhances the Nutritional Quality of Cereal-based Products

Human consumption of flaxseed is increasing due to its health benefit properties and extrusion processes can enhance its nutritional quality. Extruded flaxseed meal (EFM) obtained in a pilot plant was characterized and incorporated in flour mixes and cereal-based bars to demonstrate its nutritious usefulness. Amino acid content was not affected by extrusion and, despite lysine was the limitating amino acid, the chemical score (CS) was 83 percent. Thiamin and riboflavin decreased slightly as consequence of extrusion, phytic acid did not change and trypsin inhibitor activity was undetectable. Proximate composition and nutritional quality determined by biological and chemical indexes were compared among EFM, flour mixes (FM) and cereal bars (CB). They presented high protein levels (26, 20 and 17 percent, respectively), good biological value (BV) (80, 79 and 65, respectively), acceptable true protein digestibility (TD) (73, 79 and 78, respectively), and high dietary fiber (33, 20.5 and 18 percent, respectively). The ratio of n6 to n3 ratio for CB was within the WHO/FAO recommendations. These results open a new venue for the usefulness of nutritious/healthy extruded flaxseed flours into ready to eat cereal based products with improved nutritional quality. (Authors abstract)

Flaxseed meal is a source of high-quality protein. Lys is one of the limiting amino acid and can be complemented with cereal and legume proteins . Extrusion cooking is an economical on going food processing technology widely used for the production of textured foods. The advantages against other heating systems include versatility, high production capacity, low operating costs and shorter cooking times. The fortification of puffed, a corn meal-based product, with extruded flaxseed meal has been marketed as a ready to eat functional breakfast with potential health benefits; however, the nutritional quality of foods enriched with extruded flaxseed meal products has not been yet established. The extrusion of flaxseed could be an excellent opportunity to encourage its production and, once established its nutritional quality, guarantee its incorporation in derived food products. Therefore, the present study was aimed to characterize the composition of extruded flaxseed meal compared with raw flaxseed and to evaluate the nutritional quality of two fortified cereal based food products by biological and chemical indexes. Flour mixes (FM) were incorporated to cereal bars based on extruded peas in order to obtain an enriched ready to eat snack product of acceptable protein quality.  Consumers have the perception that cereal bars are convenient and healthy food for breakfast, aimed at children population and, even, as a portable food to consume at convenient time.
Cereal bars reached a ratio n6:n3 of 6.8:1, value within the WHO/FAO recommendations. However, since these unsaturated fatty acids are easily oxidized, this aspect will limit the shelf life of these products, otherwise antioxidants should be added. (Authors abstract)