New potato fibre for improvement of texture and colour of wheat bread

The aim of this project was to compare the functional properties of five fibre fractions by baking of wheat bread by substitution 0, 4, 8 and 12 w/w% of wheat flour using dry potato pulp (Fibre 1), a commercial potato fibre (Fibre 2), two fibre prepared from potato pulp by enzymatic hydrolysis (Fibre 3 and 4), and one solubilised fibre (Fibre 5). The effect of chemical composition of fibre on texture, colour, specific weight and volume of wheat bread was studied using objective methods for measurement of texture characteristics, colour (L, a, b) and sensory analysis. Dry potato pulp, Potex (Fibre 2) and two enzymatically prepared fibre powders (Fibre 3 and 4) with a high concentration of lignin and insoluble non-starch polysaccharides (INCP) had a detrimental effect on bread quality by substitution of more than 8% of the wheat flour by fibre. The detrimental effect was mainly due to increased hardness, deformation energy, modulus and gumminess. Multiple linear regression analysis with forward selection was used for determination of the relationship between quality characteristics and of soluble non-starch polysaccharides (SNSP), insoluble non-starch polysaccharides (INCP), cellulose and lignin. The enzymatic solubilised fibre (Fibre 5) with a high concentration of soluble fibre and a low concentration of cellulose and lignin could be used for substitution of at least 12% wheat flour for baking of bread with an attractive colour, delicious texture and flavour.