**4. Composition and nutritional value**

Quinoa is rich in protein, lipids, fiber, vitamins, and minerals. The grain contains an excellent nutritional profile (**Table 1**), starch (32–60%), protein (10–18%), fat (4.4–8.8%), fiber (1.1% and 13.4%), ash (2.3–3.7%), formed mainly from potassium and phosphorus [18, 19]. Quinoa also contains a high amount of vitamin B and vitamin E.

#### **4.1 Protein**

The average protein content is higher (12 to 23%), compared with other grains such as barley (11% dry basis), rice (7.5% dry basis) or corn (13.3% dry basis), and is comparable to wheat (15.4% dry basis) [14]. The proteins present in quinoa are of high quality, including albumins (35%) and globulins (37%) and, to a lesser extent, prolamins. The quality of these proteins is comparable to the protein present in milk (casein) [8]. It contains all the essential amino (**Table 2**), which is why it is considered a complete food [23], and it is also low in prolamine (0.5–7.0%), indicating that it is not allergenic [24].

#### **4.2 Lipids**

The fat content in quinoa seeds averages 2–10% and is considered as an alternative to oilseeds due to its lipid composition. Triglycerides are the main fraction of fats and constitute more than half of the neutral lipids [25]. Quinoa and soybean oils present a very similar fatty acid composition, with linolenic acid (18: 2n-6: 52%) and linolenic acid (18, 3n-6: 40%) being the most representative (**Table 3**) [27]. Quinoa oil has a high antioxidant quality, a high content of polyunsaturated fatty acids including

*Nutritional Value, Methods for Extraction and Bioactive Compounds of Quinoa DOI: http://dx.doi.org/10.5772/intechopen.101891*


#### **Table 1.**

*Chemical composition of quinoa (g /100 g dry weight).*


#### **Table 2.**

*Essential amino acid profile (g protein/100 g).*


#### **Table 3.**

*Saturated fatty acid (g/100 g of oil extract).*

omega-3 and omega-6 fatty acids (63% of the total), and a significant amount of tocopherols (2.5 mg/g oil) [28]. On the other hand, linoleic acid is metabolized to arachidonic acid and linolenic acid to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) [29]. Polar lipids account for about 25% of the total, composed mainly of phospholipids (lysophosphatidylethanolamine and choline), of the neutral lipids (glycerides and sterols), triglycerides account for 74% and diglycerides for 20%, while monoglycerides and waxes account for 3% [8].

#### **4.3 Carbohydrates**

Quinoa has a significant amount of carbohydrates and represents between 67% and 74%, of which starch is the most important carbohydrate and represents approximately 58.1–64.2% of dry matter, variation of which is attributed to differences in genotypes and growing conditions [24]. Its granules have a polygonal shape with a diameter of 2 μm, being smaller than those of common cereals. Due to its size, it can be used as a biodegradable filler in polymer containers [23]. It is also an ideal thickener for frozen foods and other applications where resistance to retrogradation is desired, because of its freeze–thaw stability [30]. Carbohydrates include amylose with a content of about 11%, and other carbohydrates, which have been documented, include monosaccharides (2%) and disaccharides (2.3%), crude fiber (2.5–3.9%), and marshmallows (2.9–3.6%) [27]. Sucrose is also present in significant amounts compared with other sugars [23]. It contains a low proportion of glucose (19.0 mg/100 g) and fructose (19.6 mg/100 g). This is important in the fermentation of malted beverages [31].

### **4.4 Fiber**

Quinoa is considered an important source of dietary fiber accounting for about 2.6–10% of the total dietary fiber weight. Approximately 78% of the amount of fiber in quinoa is insoluble and 22% in soluble form [24]. Although washing and abrasion processes are performed to remove saponins, this does not influence the fiber content [25]. Research reports that the dietary fiber content of quinoa is equal to that of other cereals and grains. Although, the fiber composition of quinoa is different from other cereals, biochemistry and therapeutics are still important to study the potential of quinoa and thus understand its specific physiological impact [8].

#### **4.5 Minerals**

Quinoa has a high content of calcium, iron, magnesium, iron, copper, and zinc (**Table 4**), covering the amounts needed to maintain a balanced human diet of calcium, phosphorus, potassium, and magnesium of 874, 2735.0–4543.3, 9562.2, and 1901.5 mg/kg, respectively [24]. In general, many of these minerals are higher than those reported for most cereal crops such as barley oats, rice, maize, or wheat [23].

#### **4.6 Vitamins**

The vitamin content of quinoa is interesting. It has high levels of vitamin B6 and total folate, whose amounts can cover the daily requirement of children and adults, as for riboflavin content, 100 g provides 80% of the daily needs of children and 40% of adults [14]. The niacin content does not cover the daily requirement; however, it is beneficial for the diet, the values of thiamine in quinoa are lower than those of oats and barley, but those of niacin, riboflavin, vitamin B6, and total folate are higher (**Table 5**).


#### **Table 4.**

*Mineral composition (mg/ kg dry weight).*


#### **Table 5.**

*Concentration of vitamins (mg/100 g dry weight).*

### **5. Processed uses and current situation**

At present, the processed uses given to quinoa are mainly from the flour obtained from it, which can replace that of corn and wheat, since various levels of quinoa flour substitution have been reported, for example, in sweet biscuits (60% quinoa), in noodles and pasta (30–40%), and in bread (10–13%) [27]. Other uses or innovations include quinoa beer that meets the sensory acceptance requirements, reaching a high alcoholic content (between 48 and 74°GL) and for the production of chocolates with quinoa filling with good physicochemical, organoleptic, microbiological, and nutritional characteristics [34].

There are other potential products derived from quinoa, which are obtained by extracting compounds from quinoa and for the creation of value-added products. Examples of these products are oil extraction, protein concentrates and isolates, starches, bioactive compounds, among others, for use in the food and pharmaceutical industry (**Table 6**, [35]). Compared with the starch content of wheat and barley, quinoa starch has a higher viscosity, greater water retention, and expansion capacity, as well as a higher gelatinization temperature, which translates into better performance as a thickening agent. Due to these properties, quinoa starch is very suitable for the production of prepared frozen baby foods, as it shows good freeze–thaw stability [36]. Due to its protein and starch content, quinoa can be used for the production of

*Nutritional Value, Methods for Extraction and Bioactive Compounds of Quinoa DOI: http://dx.doi.org/10.5772/intechopen.101891*


#### **Table 6.**

*Uses and processing methods.*

edible films and as an emulsion stabilizing agent, specifically for Pickering emulsions [37]. Even incorporation of quinoa into food products has been shown to help extend shelf life and reduce microbial spoilage of food products.
