Fibre concentrates from apple pomace and citrus peel as potential fibre sources for food enrichment

Research to evaluate some functional properties of fibre concentrates from apple and citrus fruit residues, in order to use them as potential fibre sources in the enrichment of foods, was carried out. Fiber concentrates were analysed for their proximate content (moisture, lipids, protein and ash); caloric value; dietary fibre composition and functional properties (water retention capacity - WRC, swelling capacity - SW, fat adsorption capacity - FAC and texture). All the fibre concentrates had a high content of dietary fibre (between 44.2 and 89.2 g/100 g DM), with a high proportion of IDF. Protein and lipid contents ranged between 3.12 and 8.42 and between 0.89 and 4.46 g/100 g DM, respectively. The caloric values of concentrates were low (50.8-175 kcal/100 g or 213-901 kJ/100 g). Grapefruits had the highest WRC (2.09-2.26 g water/g DM) high SW and FAC. Texture was strongly dependent on the particle size and it was increased by the heat treatment. Every concentrate studied had interesting characteristics, suggesting possible uses in the development of fibre enriched foods.