## 3 Results and Discussion
### Chemical and Nutritional Characteristics of Bean Extrudates
#### 3.2.2 Nutritional Components in Extruded Beans  
Extraction of phenolic compounds from extruded samples is easier than in untreated been seeds so the results of phenolics content clearly differentiate bean cultivars used in the experiment. With red Toska bean, if more water was applied, the results of total phenols content lowered significantly. The highest phenols content was found in Toska extrudates processed at 0.8 and 1.2 1 h\({}^{-1}\) of water and with low screw speeds of 300 and 400 rpm (Table 1). These conditions seem to be the most efficient to make an easy extraction procedure with functional components due to intensive shearing in the presence of very low water in the processed material. This generates an intensive mechanical treatment and thus a higher amount of extractable phenolic compounds may be reached. [PERSON] et al. [58] confirmed that high feed moisture protects phenolics from degradation, thus maintaining their stability especially at low temperature extrusion. They reported increased TPC at increased screw speed as a result of dual effect of high shear and low residence time at high screw speeds. High shearing and friction may cause degradation of cell walls, breakdown of conjugated or bound phenols and much easier release of free phenolic acids as well as minimizing thermal degradation by reduction of the residence time and thus high retention of phenolics [58]. A few times, lower results were found in Aura bean extrudates, total phenols content varied from 0.81 to 2.94% and here the effect of processing variables was not so evident (Table 2). Anthocyanins are red colorants naturally present if plants and food containing dark plant additives. Anthocyanins are water-soluble vacuolar pigments that, depending on their pH, may appear red, purple, blue or black. They are responsible for most of the red, purple and blue colours exhibited by flowers, fruits and other plant tissues and have found application in the food industry as natural colorants [59]. Antioxidants, which can neutralize free radicals, may be important in the prevention of a number of diseases including cancer and atherosclerosis. Anthocyanin pigments may be used for colouring foodstuffs and snack food, beverages, pharmaceutical and cosmetic products, etc. The level of anthocyanin pigments may depend on plant cultivar, growing conditions, storage conditions or processing parameters. Red pigments due to the presence of many unsaturated are also sensitive to light so naturally red in colour products, should be protected from direct sunlight during storage by dark package. In the present study the level of anthocyanins in extruded red Toska bean varied from 0.010 to 0.093 mg/g and it was clearly visible that at high water content in material processed at low screw speed the content was much higher than at increased screw speed (Table 1). So, mechanical effects seem to be more important in red pigment degradation than water in the feed material. In the Aura bean cultivar, after extrusion anthocyanin pigments were not present because of the white colour of Aura seeds. [PERSON] and co-workers [60] investigated whether mulberry-extrudate solid formulations had a positive impact on the stability of anthocyanins. Mulberry fruits are rich sources of anthocyanins that exhibit beneficial biological activity. They found the mulberry-extrudate solid formulations extruded in the presence of an ionization agent and sodium alginate contained a large number of available anthocyanins even after being incubated for 180 min in the intestinal fluid system. Thus, hot-melt extrusion enhanced the water solubility and stability of anthocyanins with prolonged release. So, it can be stated that even under extrusion conditions anthocyanins could be stable. [PERSON] et al. [61] tested the suitability of anthocyanin during pre-extrusion of coloured rice as a function of extrusion parameters: moisture content, screw speed and temperature of extrusion.