# Physical and Functional Characteristics of Extrudates Prepared from Quinoa Enriched with Goji Berry
## 1 Introduction  
Phenolic substances in plants possess various biological and nutritional effects [1, 2], Quinoa (_Chenopodium quinoa_) has a high protein content and a remarkable amino acid profile, for example, lysine and sulfur amino-acids; therefore, it has been assigned by NASA to the novel products with notable nutritional properties for long-duration missions in space [3]. The composition of quinoa also includes minerals, oils, starch, as well as several vitamins and antioxidants [4]. The authors of [5] confirmed the high antioxidant activity of the polyphenols in quinoa. The phenolic substances of quinoa were related to antioxidative, antiradical, and antitumor effects in the human body [6]. The availability of bioactive compounds in quinoa showed the possibility of its use for dietetic foods. The goji berry (_Lycium barbarum_ L.) traditionally originates from Asian countries where the fruits has been applied in alternative medicine and functional foods [7, 8]. An ample amount of its composition consists of polysaccharides, and their presence is related to various biological properties, for example, rejuvenating and reducing the effects of fatigue, neuroprotective effect, improved metabolism, glucose reduction for diabetics, antioxidant and anti-tumor ability, increased immunity, etc. [8, 9]. It was established that thegoji berries improved the feelings of overall well-being, tiredness, stress, neurological, stomach and muscular problems, blood pressure, visual capacity [10; 11], plasma values of anti-oxidants [12], and immune factors [13]. The extrusion process has been widely used all over the world for the production of expanded foods, breakfast cereals, and pet foods [14]. This process possesses many advantages in comparison to other food technologies due to the short processing time and its continuous nature [15]. Despite the popularity of the extrusion processes in food and feed production, there are still missing data concerning the raw materials and extruder conditions of some products [16]. The investigations of the authors of [15; 17] showed that quinoa can be successfully used for production of extruded foods. The authors of [15] extruded quinoa flour and investigated the effect of feed moisture content, temperature, and screw speed on the physicochemical properties of extrudates. Similar investigations were carried out in [17] for ten novel quinoa breeding lines. The incorporation of fruits in extrudates improves not only the content of healthy compounds but also the attractive appearance of the final product [18]. The authors of [19] used different fruits in extruded snacks for children's diets and studied the interactions between the type of fruit (banana, apple, strawberry, tangerine), extrusion process, and the physical properties of the resulting product. The incorporation of the goji berry in extrudates results in products with a high content of bioactive substances and high antioxidant activities [18; 20]. The authors of [18] added dried goji berries in a mixture of rice flour, wheat flour, sucrose, and whey protein and investigated the physical properties and antioxidant activity of the extruded product. Similar investigations were carried out in [20], where various amounts of goji berry powders (from 3 to 20%) were added to rice flour. According to [21], the carbohydrates, proteins, and fibers in the raw material influenced the properties of the extruded products. The same authors enriched corn grits with dried goji berries and cranberries (from 1 to 5%) and studied the functional characteristics of the extrudates--the water absorption index (WAI), water solubility index (WSI), and color characteristics. There is no found literature on the enrichment of quinoa extrudates with goji berries.