**3.1.3 Fibers and resistant starch**

Céspedes et al. (2010) obtained extruded orange pulp using a Brabender laboratory singlescrew extruder (20:1 Céspedes 2010) and observed that it could also be added to high-fiber foods as a low-calorie bulk ingredient to reduce the calorie level, since it showed potential hypoglycemic effects.

Souza & Lionel (2010) verified that the mixture of cassava starch and dried orange pulp extruded under different conditions (0 to 20% of fibers in the mixture), (14.6 to 21.4% moisture), and (60.8 to 129°C temperature of extrusion), could aim at the use in high-fiber instant products.

Bello-Pérez et al. (2006) extruded starches isolated from unripe banana (*Manguifera indica* L.) and mango (*Musa paradisiaca* L.) fruits to obtain a product with high content of resistant starch (RS) and verified that RS formation in the extruder for banana starch was affected positively by temperature and inversely by moisture. Moisture did not significantly affect RS formation in mango starch.

Two types of products were produced: pure whole meal products and breakfast cereals made from whole meal/maize blends were processed by pilot-plant extrusion and the enzyme-resistant starch (RS) content and hydrolysis index (HI) were not correlated to the extrusion temperature, but with whole meal products (Chaunier et al., 2007).

Yanniotis et al. (2007) verified the effect of pectin alone or in combination with wheat fiber on the physical and structural properties of extruded cornstarch, under specific moisture content, barrel temperature and screw speed conditions were studied using a laboratory single-screw extruder. These authors observed that fibers reduced the size of the cells and increased their number and pectin increased porosity and reduced expansion ratio and hardness of the snacks.

Stojceska et al. (2009) investigated the use of brewer's spent grain and red cabbage barley and red cabbage in wheat flour and corn starch extruded in co-rotating twin-screw extruder, under the conditions studied, the results were promising towards the increase of total dietary fibre and the level of total antioxidant capacity and total phenolic compounds of the snacks.
