Quinoa (Chenopodium quinoa Willd.) is a pseudocereal belonging to the Amaranthaceae family that is native to the Andean region in South America. Peru is the leading quinoa-exporting country, exporting quinoa with a value of $98.5 million dollars, followed by Bolivia, the Netherlands, the United States, Spain, Germany, Canada, France, Ecuador, and Belgium.
1. Introduction
Quinoa seeds are known to have a high protein content ranging from 11% to 19%. The seeds are a source of amino acids (isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, histidine, cysteine, tyrosine, glycine, arginine, proline, serine, glutamine, alanine, and aspartic acid), carbohydrates (49% to 68% dry weight), fat (2% to 9.5%), vitamins (thiamine, riboflavin, folic acid, and niacin), and minerals such as iron, zinc, magnesium, and copper (2.4% to 4.8%)
[3][1]. Additionally, some phytochemical constituents such as saponins, phenolic compounds (ferulic, sinapinic and gallic acids, kaempferol, isorhamnetin, and rutin)
[4][2], and peptides with therapeutic activity have been determined, making this crop very attractive for a wide range of food products
[5][3]. Quinoa has been traditionally used in tortillas, pasta, flour, cookies, bread, and soups, among others, and is considered to be a gluten-free superfood and a source of fiber dietary
[6][4]. Thus, quinoa is considered to be an acceptable food worldwide and is highly recommended for vegetarians.
On the other hand, sprouts are obtained by germinating the seeds and provide multiple nutritional and therapeutic benefits to those who consume them in different ways, due to the increase in the availability of nutrients such as fatty acids and carbohydrates, as well as polyphenols and flavonoids, during the germination process, which improves their antioxidant capacity
[7][5]. These changes are due to a multitude of biochemical processes, which generate alterations in the composition of primary and secondary metabolites, producing an intrinsic change in the phenolic compounds and antioxidant activity
[8][6]. Sprouts can improve the nutritional quality of a grain by eliminating or inactivating some antinutritional factors and increasing the digestibility of proteins and starches
[9][7]. During germination, the original composition of the seed changes: the nitrogen-containing proteins move towards smaller protein fractions, oligopeptides, and free amino acids (some increase; others decrease or are not altered). Consequently, the changes increase the biological protein value of the sprouts, and digestibility is higher than in seeds
[10][8].
Studies have reported that quinoa sprouts have high levels of amino acids, peptides, vitamins, and minerals but also include antinutritional components such as tannin, lectin, trypsin inhibitor, and galactoside, although at lower values than in non-germinated seeds
[11][9]. The main enzyme involved in the early phase during the sprouting of quinoa seeds seems to be α-amylase, which leads to the generation of new compounds
[12][10]. Some biological studies in quinoa sprouts have reported hepatoprotective, antioxidant
[13][11], and anti-α-amylase effects in vitro
[14][12], and hypoglycemic effects in diabetic rats
[15][13].
2. Germination Process
Sprouts were obtained in a time of 72 h, and measured between 1.7 and 2.3 cm in length for all varieties. However, the red variety achieved the greatest length among all varieties (2.1–2.3 cm). The other varieties had lengths as follows: White Junín Ayacucho, 1.7–1.9 cm; T-256, 1.8–1.9 cm; Pasankalla, 1.7–1.8 cm; Suano Puno, 1.7–1.9 cm; T-38, 1.8–2.0 cm; Yellow Sacaca, 1.9–2.0 cm; T-45, 1.7–1.9 cm; Santa Ana, 1.7–1.8 cm; T-61 Pomata, 1.8–1.9 cm; CQA-048, 1.8–2.0 cm; Black Collana, 1.7–1.9 cm; T-72 Huancayo, 1.8–1.9 cm; CQA-043, 1.8–1.9 cm; Salcedo, 1.8–2.0 cm; Ayacucho Compuesto, 1.7–1.9 cm; White Choclito, 1.7–1.9 cm; Yellow Maranganí, 1.9–2.1 cm; Black Coito, 1.7–1.9 cm; and Black, 1.8–2.0 cm.
Figure 1 shows the 20 varieties of quinoa germinated under standard laboratory conditions of temperature, humidity, and time.
Figure 1. Twenty varieties of quinoa sprouts. (1), White Junín Ayacucho; (2), T-256; (3), Pasankalla; (4), Suano Puno; (5), T-38; (6), Yellow Sacaca; (7), T-45; (8), Santa Ana; (9), T-61 Pomata; (10), CQA-048; (11), Black Collana; (12), T-72 Huancayo; (13), CQA-043; (14), Salcedo; (15), Ayacucho Compuesto; (16), White Choclito; (17), Red; (18), Yellow Maranganí; (19), Black Coito; (20), Black.
3. Total Phenolic Content
The TPC of sprouts was found to range from 19.15 ± 1.54 to 31.28 ± 0.42 mg GAE/g of methanolic extract, being highest in the Pasankalla variety, CQA-048, Black Collana, and Black Coito. On the other hand, in quinoa seed extracts, the variation was from 11.72 ± 0.32 to 28.32 ± 0.49, being greater in the Pasankalla, Black Collana, and Black Coito varieties (
Table 1). There was a significant difference between sprout and seed extracts for TPC, (paired sample t-test;
p < 0.05), with TPC being higher in sprout extracts than in seed extracts, with an average of 24.57 ± 3.49 mg GAE/g in sprout extracts and 20.12 ± 4.37 mg GAE/g in seed extracts.
Table 1. Total phenolic content (TPC) and total flavonoids (TF) in the sprouts and seeds of 20 varieties of quinoa.
Variety |
TPC mg EAG/g ME |
TF mg EQ/g ME |
Quinoa Sprouts Mean ± SD |
Quinoa Seeds Mean ± SD |
Quinoa Sprouts Mean ± SD |
Quinoa Seeds Mean ± SD |
|
23.32 ± 1.63 |
20.95 ± 0.79 |
11.52 ± 0.26 |
8.77 ± 0.26 * |
- 2.
-
T-256
|
24.78 ± 0.21 |
13.82 ± 1.04 * |
11.23 ± 0.19 |
10.23 ± 0.95 |
- 3.
-
Pasankalla
|
31.28 ± 0.42 |
28.32 ± 0.49 * |
13.48 ± 0.38 |
11.52 ± 0.92 * |
- 4.
-
Suano Puno
|
19.62 ± 0.42 |
17.25 ± 0.66 * |
8.60 ± 0.48 |
8.56 ± 0.38 |
- 5.
-
T-38
|
21.05 ± 0.40 |
21.75 ± 1.25 |
10.06 ± 0.57 |
9.81 ± 0.25 |
- 6.
-
Yellow Sacaca
|
24.22 ± 0.31 |
23.58 ± 0.61 |
11.19 ± 0.38 |
8.23 ± 0.29 * |
- 7.
-
T-45
|
21.02 ± 0.15 |
19.38 ± 2.06 |
11.06 ± 0.21 |
8.39 ± 0.38 * |
- 8.
-
Santa Ana
|
23.02 ± 0.74 |
18.23 ± 1.01 * |
9.94 ± 0.63 |
7.06 ± 0.33 * |
- 9.
-
T-61 Pomata
|
21.12 ± 1.50 |
15.55 ± 0.20 * |
10.94 ± 0.33 |
8.73 ± 0.31 * |
- 10.
-
CQA-048
|
28.82 ± 0.67 |
21.32 ± 0.72 * |
7.44 ± 0.50 |
6.23 ± 0.26 * |
- 11.
-
Black Collana
|
28.58 ± 1.21 |
26.98 ± 0.25 * |
13.44 ± 0.58 |
8.73 ± 0.14 * |
- 12.
-
T-72 Huancayo
|
19.15 ± 1.54 |
18.58 ± 0.65 |
12.35 ± 0.48 |
9.81 ± 0.45 * |
- 13.
-
CQA-043
|
26.05 ± 0.17 |
11.72 ± 0.32 * |
12.15 ± 0.08 |
11.31 ± 0.50 |
- 14.
-
Salcedo
|
20.98 ± 1.99 |
12.38 ± 0.61 * |
11.94 ± 0.13 |
9.81 ± 0.45 * |
- 15.
-
Ayacucho Compuesto
|
28.05 ± 0.53 |
21.42 ± 1.17 * |
11.19 ± 0.25 |
10.98 ± 0.40 |
- 16.
-
White Choclito
|
24.02 ± 0.78 |
20.78 ± 1.86 |
11.52 ± 0.31 |
9.90 ± 0.26 * |
- 17.
-
Red
|
26.05 ± 0.36 |
20.45 ± 0.44 * |
12.31 ± 0.50 |
10.52 ± 0.19 * |
- 18.
-
Yellow Maranganí
|
27.98 ± 0.70 |
22.82 ± 1.12 * |
13.52 ± 0.44 |
10.98 ± 0.52 * |
- 19.
-
Black Coito
|
28.18 ± 0.35 |
24.42 ± 0.75 * |
14.31 ± 0.50 |
9.94 ± 0.13 * |
- 20.
-
Black
|
24.12 ± 0.64 |
20.78 ± 0.35 * |
12.31 ± 0.45 |
9.73 ± 0.38 * |
Total Average ± SD |
24.57 ± 3.49 |
20.12 ± 4.37 * |
11.52 ± 1.67 |
9.46 ± 1.40 * |