Effect of hydrated apple powder on dough rheology and cookies quality

Dietary fiber is a group of food components, which are resistant to human enzymatic digestion. The incorporation of dietary fiber obtained from various sources of fruit and vegetable by-products into the cereal based products such as bread, rolls, cookies, muffins, crackers, cakes and pasta is of growing interest for the food industry. The replacement of wheat flour by dietary fiber from various sources can change physicochemical, textural and organoleptic characteristic of bakery products. Apple pomace is the main by-product produced in the apple fruit processing industry. It is a rich source of carbohydrate, pectin, crude fiber, and minerals. The dietary fiber content in apple pomace ranges between 33 - 35%. The influence of hydrated commercial dietary fiber on wheat dough rheology (5, 10 and 15% flour replacement) and physical and sensory properties of cookies was examined. It was found that addition of HAP significantly increased the rheological properties of dough such as water absorption (from 58.0% to 75.3%), dough stability (from 6.7 min to 11.6 min) and prolonged dough development time (from 3.5 min to 11.0 min) and reduced the mixing tolerance index (from 34.7 BU to 11.9 BU). It was also concluded that hydrated apple powder addition reduced physical properties of cookies such as volume (from 10.4 cm3 to 8.0 cm3), diameter (from 4.7 cm to 4.2 cm), volume index (from 1.35 cm to 1.10 cm) and porosity (from 0.32 to 0.24). Sensory properties (taste, odour, stickiness, firmness and density) of cookies were also analysed. Cookies with addition of hydrated apple powder had fruity taste and odour and showed high overall acceptance. From this study resulted that hydrated apple powder can be used as potentially source of dietary fiber in cookie formulation. Moreover, addition of apple pomace inhibits the use of any other flavouring ingredients because has a pleasant fruity flavour.