Within the functional foods market, a global annual demand growth of 15% has been estimated between 2023 and 2028 (Rachtan-Janicka et al., 2025). This increase is attributed to a society that is more aware of healthier lifestyles and follows a growing trend toward consuming foods that provide positive health benefits, ranging from better body weight control to slowing the progression of chronic diseases (Vajdovich et al., 2025).
       
Pseudocereals such as quinoa and amaranth are considered ingredients with functional potential due to their numerous health benefits associated with their high nutritional and phytochemical profiles (Jan et al., 2023; Toimbayeva et al., 2025). Quinoa (Chenopodium quinoa Willd.) possesses a balanced combination of essential amino acids and is a good source of minerals and proteins, some of which are present in higher amounts than in traditional cereal crops but also is low in prolamins which indicates that it is gluten free and, therefore, non-allergic (Anuhya and Dobhal, 2024). It also contains a wide variety of antioxidant compounds, such as phenolics (Jan et al., 2023) and furthermore, quinoa contains polysaccharides that have a prebiotic action (Mu et al., 2023). Amaranth (Amaranthus spp.), similar to quinoa, is characterized by a balanced amino acid composition, including essential amino acids. It is also rich in dietary fiber, minerals, as well as antioxidants such as polyphenols (Toimbayeva et al., 2025).
       
Despite these attributes, both quinoa and amaranth exhibit limited bioavailability due to antinutritional factors (tannins, phytic acid and saponins) that bind to nutrients, reducing their availability for absorption. Soaking, germination and thermal treatments are useful methods for reducing antinutritional compound content while simultaneously improving nutritional value and bioactive potential (Thakur et al., 2021; Li et al., 2025).
       
Germination is an effective process for improving the nutritional properties of grains through various biochemical reactions. This process begins with water imbibition, which activates the seed’s metabolism and concludes with radicle elongation (Zhang et al., 2024; Benincasa et al., 2019). Likewise, germination activates antioxidant synthesis as a protective mechanism against oxidative damage induced by enzymatic activation, while also increasing the levels of free and bound phenolic compounds (Aung et al., 2022). In addition to nutrient activation, the antinutritional compounds naturally present in the seed are reduced, resulting in improvements in both flavor and digestibility (Thepthanee et al., 2024).
       
Although germination improves the nutritional and sensory characteristics of grains, excessive germination periods may promote microbial growth and the development of undesirable flavors. Therefore, post-germination treatments, such as roasting, are considered viable methods for preservation and flavor enhancement, as they suppress organic acids, including acetic and ethanoic acids, formed during germination (Kim et al., 2021).
       
Germinated and/or roasted pseudocereals can be used as ingredients to make basic dough for pasta and baked gluten free products (cookies, bread, pancakes) and beverages, which have shown higher nutritional and functional properties than raw flours (Schmidt et al., 2023; Pilco-Quesada et al., 2020; Jyoti et al., 2025; Muyonga et al., 2014).
       
The aim of the present study was to evaluate the effect of germination and roasting on the nutritional, chromatic and functional properties of quinoa (Chenopodium quinoa Willd.) and amaranth (Amaranthus spp.) flours.

Experimental site
 
The experiments were conducted at Chemistry and Biochemistry Lab in the Agronomy Faculty of Universidad Autónoma de Nuevo León from February to November 2025.
 
Plant material
 
Quinoa (Chenopodium quinoa Willd.) seeds were obtained from different commercial establishments in the city of Monterrey and its metropolitan area, with Bolivia and Peru as countries of origin. Amaranth (Amaranthus hypochondriacus L.) seeds were obtained from the state of Puebla, Mexico.
 
Seed treatment
 
For the preparation of non-germinated quinoa (Q-NG) and amaranth seed (A-NG) seeds, 10 g sample were dried at 50°C for 24 h, roasted at 145°C for 30 min (Felisa, 291A), milled, sieved to 60 mesh (0.25 mm) and stored at -20°C, protected from light, until further analysis.
       
The germinated quinoa (Q-G) and germinated amaranth (A-G) samples were obtained according to the method described by Choque-Quispe et al. (2021) with some modifications. A 10 g sample was weighed and disinfected with commercial sodium hypochlorite (500 ppm) for 5 min. After that, the samples were rinsed with bidistilled water by hand-friction to remove saponins until no foam was observed. The seeds were then soaked in darkness for 2.5 h at 25°C, following by excess water removing and they were placed on filter paper inside of germination boxes for 72 h. After germination, the samples were dried at 50°C for 24 h, roasted at 145°C for 30 min (Felisa, 291A), ground, sieved to 60 mesh (0.25 mm) and stored at -20°C, protected from light, until further analysis.
 
Proximate composition
 
Proximate analysis of flour samples was conducted following the Association of Official Analytical Chemists AOAC (2000) and American Oil Chemists’ Society (AOCS). The content of moisture, ash and crude protein were obtained by AOAC methods 925.10, 923.03 and 960.52, respectively, while the content of crude fiber and crude fat was obtained by AOCS methods Ba 6a-05 (AOCS, 2005) and Am 5-04 (AOCS, 2004), respectively. The total carbohydrates content was obtained by difference.
 
Color evaluation
 
Flour color parameters were obtained according to Ramírez-Cortez et al. (2025) using a Minolta® colorimeter (model CR-20, Japan). A petri dish was filled with flour and chromatic parameters were obtained using CIELAB (L*, a*, b*) and CIELCH (L*, C*, h*) color systems according to International Commission of Illumination (CIE, 2004). In these color systems, L* defines lightness (0= black, 100= white), a* indicates red (positive a*) or green value (negative a*), b* indicates yellow (positive b*) or blue value (negative b*). In addition, C* indicates saturation level of h* and h* indicates a color tone (0°= red, 90°= yellow, 180°= green and 270°= blue). Color view of flours was obtained by online software ColorHexa color converter using L*, C* and h* values (ColorHexa, 2024).
 
Phenolic compounds and antioxidant capacity
 
Extraction of phenolics, phenolic content and antioxidant capacity assays were carried out as described by Rodríguez-Salinas et al. (2020), with some modifications.
 
Extraction of free and bound phenolic compounds
 
For the extraction of free phenolic compounds, 0.2 g of dry sample was mixed with 3 mL of 80% methanol, purged with gaseous nitrogen for 30 s and shaken for 2 h at 250 rpm (Labnet, Orbit 1900). Subsequently, the samples were centrifuged at room temperature for 10 min at 4,600 rpm (Eppendorf, 5804 R-15 AMP version) and the supernatant was recovered in amber flasks and stored at -20°C.
       
The extraction of bound phenolic compounds was performed using the precipitate obtained from the previous procedure by adding 9 mL of 2 M NaOH. The samples were purged with gaseous nitrogen and shaken for 2 h. Afterwards, the pH of the samples was adjusted to 2 using concentrated HCl and the phenolic compounds were extracted twice with 6 mL of diethyl ether. The diethyl ether extracts were combined, centrifuged at 4,500 rpm (25°C, 5 min), evaporated using a rotary evaporator at 40°C (Yamato Rotary Evaporator RE200, Yamato Water Bath BM200) and stored at -20°C. Prior to determining phenolic compounds and antioxidant capacity, the samples were resuspended in 80% methanol.
 
Total phenolics, total flavonoids and condensed tannins
 
Total phenolics content was determined using the Folin-Ciocalteu assay. A 0.2 mL aliquot of the sample was used, followed by the addition of 2.6 mL of bidistilled water and 0.2 mL of Folin-Ciocalteu reagent for oxidation. After 5 min, the reaction was neutralized with 2 mL of 7% sodium carbonate (Na₂CO₃). The samples were allowed to react for 90 min in the dark. Sample absorbance was measured at 750 nm. A calibration curve was prepared using gallic acid (0-200 mg/L) and the results were expressed as milligrams of gallic acid equivalents per kg of dry sample (mg GAE/kg).
       
Total flavonoids were evaluated using the aluminum chloride colorimetric method. A 0.2 mL aliquot of the sample was mixed with 3.5 mL of bidistilled water and 0.15 mL of 5% sodium nitrite (NaNO₂). After 5 min, 0.15 mL of 10% aluminum chloride (AlCl₃) was added and after another 5 min, 1 mL of 1 N sodium hydroxide (NaOH) was incorporated. The samples were allowed to react for 15 min in the dark. Absorbance was measured at 510 nm. Catechin was used to construct a calibration curve (0-200 mg/L) and the results were reported as milligrams of catechin equivalents per kg of dry sample (mg CE/kg).
       
Condensed tannins were determined using the vanillin-sulfuric acid (H₂SO₄) assay. A 0.4 mL aliquot of the sample was mixed with 1.3 mL of 1% vanillin solution, then with 1.3 mL of 25% H₂SO₄ (Both prepared in 80% methanol). The samples were incubated at 30°C for 15 min. Absorbance was measured at 500 nm. A calibration curve was prepared using catechin (0-200 mg/L) and the results were reported as milligrams of catechin equivalents per kg of dry sample (mg CE/kg).
 
Antioxidant capacity
 
For the determination of antioxidant capacity by DPPH, a working solution at a concentration of 60 µM (in 80% methanol) was prepared and its absorbance was adjusted to 1.0 at a wavelength of 517 nm. A 0.05 mL volume of extract was mixed with 1.5 mL of the DPPH working solution, samples were allowed to react for 30 min at room temperature in darkness and finally absorbance was measured.
       
The ABTS antioxidant capacity assay was initiated preparing a working solution by mixing 1 mL of 7.4 mM ABTS and 1 mL of 2.7 mM potassium persulfate (K₂S₂O₈), which was allowed to react for 12 h protected from light. After this reaction period, the absorbance of the ABTS working solution was adjusted to 1.0 at 734 nm using 80% methanol. Subsequently, 0.05 mL of the sample was mixed with 1.5 mL of the ABTS working solution. Absorbance was recorded after 30 min of reaction in darkness at room temperature.
       
FRAP antioxidant capacity was determined using a working solution prepared from a mixture of 300 mM sodium acetate (C₂H₃NaO₂·3H₂O, pH 3.6), 10 mM TPTZ (2,4,6-tripyridyl-s-triazine in 40 mM HCl) and ferric chloride hexahydrate (FeCl₃·6H₂O) in a 10:1:1 ratio (v:v:v). A 0.05 mL volume of the sample was mixed with 1.5 mL of the FRAP working solution and absorbance was measured at 593 nm after 30 min at 37°C.
       
For all three antioxidant capacity assays, calibration curves were prepared using Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) at concentrations ranging from 0 to 500 µmol/L. Results were reported as micromoles of Trolox equivalents per kg of dry sample (µmol TE/kg).
 
Statistical analysis
 
Data were expressed as mean ± standard deviation (n = 3) and they were analyzed as a completely randomized design with a general linear model procedure using Tukey’s test for mean comparison with statistical significance of p≤0.05 by using Minitab statistical software 17.0.

Proximate composition
 
The proximate composition of roasted non-germinated and roasted germinated quinoa and amaranth flours is shown in Table 1. Moisture content (%) showed statistically significant differences (p≤0.05) among the evaluated treatments, with A-NG showing the highest moisture at 5.23%, followed by 4.61%, 4.33% and 4.31% for Q-NG, Q-G and A-G, respectively.


       
Similarly, ash content (%) showed statistically significant differences (p≤0.05) among treatments, with values of 3.35%, 2.52%, 2.50% and 2.28% for A-G, A-NG, Q-NG and Q-G, respectively.
       
Regarding protein content (%), no significant differences were observed among treatments (p≥0.05), with values of 11.36%, 11.15%, 10.49% and 11.80% for Q-NG, A-NG, Q-G and A-G, respectively. On the other hand, fat content (%) showed significant differences among treatments (p≤0.05), with values of 6.98% in Q-G, followed by 6.86% in Q-NG, 6.10% in A-NG and 5.33% in A-G.
       
Concerning crude fiber content (%), no significant differences were observed among treatments (p≥0.05). The recorded values were 1.96% for Q-NG and 1.84%, 1.19% and 1.87% for A-NG, Q-G and A-G, respectively. Finally, carbohydrate content (%) was not significantly different among treatments (p≥0.05), with values of 72.76% for Q-NG, 73.19% for A-NG, 74.77% for Q-G and 73.39% for A-G.
       
The recorded moisture content (%) was slightly similar to the values reported by Mukunzi and Ryee (2025) in roasted tricolor quinoa (120°C, 8 min) and by Tekgül et al. (2023) in roasted chickpea (Cicer arietinum L.) (250°C, 3 min), with values of 4.97% and 4.52%, respectively.
       
Ash content (%) differed from that reported by Mufari et al., (2024) in germinated quinoa (1.89%) and by Kang et al., (2022), who reported 1.45% and 1.38% in germinated red-pigmented rice (30 h) and germinated red-pigmented rice subsequently roasted (180°C, 6 min), respectively. Although these authors observed a slight decrease after roasting, the change was not significant.
       
Guardianelli et al., (2019) observed an increase in protein content (%) in germinated amaranth (Amaranthus caudatus) flour from 14.4% to 15.5% after 24 h of germination. On the other hand, Tekgül et al. (2023) confirmed a decrease in protein content (%) in roasted chickpea, from 21.53% to 18.46% (250°C, 3 min) and 19.57% (150°C, 5 min), which could be attributed to protein denaturation and the possible loss of volatile nitrogenous compounds induced by the application of high temperatures.
       
Regarding fat content, Ramos-Pacheco et al. (2024) identified a slight decrease after 72 h of germination in white quinoa, from 6.60% to 6.44%, similar to the findings of Beniwal et al., (2019) in quinoa flour, where fat content decreased from 8.1% to 5.26% after germination and from 8.1% to 6.06% after roasting. In germinated amaranth flour, they found a decrease in fat content from 7.53% to 4.06%, while in roasted amaranth flour, it decreased from 7.73% to 5.66%. The reduction in fat content may be attributed to the activation of lipolytic enzymes during germination and the subsequent hydrolysis of lipids into fatty acids and glycerol for embryo development.
       
Joshi et al., (2026), reported a decrease in crude fiber content in germinated amaranth flour from 5.31% to 2.58% after roasting at 120°C for 10 min. A similar decreasing trend in fiber content was reported by Chauhan et al., (2022) in roasted black soybean (Glycine max L.), where values decreased from 6.23% to 6.12% under roasting conditions of 180°C for 10 s. This decrease may be related to changes in cell wall structure induced by the high temperatures applied, which break weak polysaccharide-glycosidic bonds within the fiber matrix, thereby facilitating depolymerization and subsequent solubilization (Oboh et al., 2010).
       
Finally, Mukunzi and Ryee (2025) reported an increase in carbohydrate content from 69.01% to 71.59% in roasted tricolor quinoa, attributed to the concentration of macronutrients resulting from high-temperature processing.
 
Color evaluation
 
Color parameters are shown in Table 2. All evaluated chromatic properties were significantly different (p≤0.05) among treatments. A decrease in lightness (L*) was observed in the samples after germination, with values of 72.17, 78.73, 64.67 and 61.90 for Q-NG, A-NG, Q-G and A-G, respectively.


       
The samples showed higher values of the chromatic parameter a* after germination, with A-G showing the highest at 9.17, followed by Q-G, Q-NG and A-NG at 8.57, 8.00 and 6.17, respectively, indicating a greater red hue after germination. The chromatic parameter b* showed values of 23.90, 21.03, 20.03 and 19.90 for Q-G, A-NG, Q-NG and A-G, respectively.
       
Regarding chroma (C*) of the samples, the highest value was recorded in Q-G with 25.40, while the lowest value was observed in Q-NG with 21.60. The remaining treatments presented values of 21.93 and 21.90 for A-G and A-NG, respectively. Finally, hue angle (h*) values showed a tendency toward yellow tones, ranging from 65.27 in A-G to 73.77 in A-NG, with intermediate values of 68.27 in Q-NG and 70.37 in Q-G.
       
Joshi et al., (2026), individually applied germination (72 h) and roasting (120°C, 10 min) treatments to amaranth seeds, obtaining L* values of 76.47 and 75.96; a* values of 3.64 and 5.95 and b* values of 22.17 and 25.10, respectively. These results show slight similarity in the trend of decreased lightness and increased reddish and yellowish tones after roasting, due to non-enzymatic browning reactions such as the Maillard reaction and caramelization.
       
Beniwal et al., (2019) also applied germination and roasting (180°C, 10 s) individually to white quinoa and amaranth. They reported a decrease in L* values for quinoa flour from 76.38 to 73.59 and 72.47, respectively. For a*, the reported values increased slightly from 0.62 to 0.63 after germination, then increased further to 4.44 after roasting. Regarding b*, values decreased from 15.28 to 13.46 during germination and subsequently increased to 21.65 after roasting.
       
For amaranth flour, they recorded a decrease in L* values from 78.35 to 71.47 and 70.44 for the previously mentioned treatments, respectively. Conversely, the reddish hue parameter a* increased from 1.31 to 1.41 and 6.62, respectively, while b* values slightly decreased from 13.95 to 12.34 after germination and increased to 24.55 after roasting.
 
Phenolic compounds in free fractions
 
The content of total phenolics (mg GAE/kg), total flavonoids (mg CE/kg) and condensed tannins (mg CE/kg) in the free extracts of non-germinated and germinated quinoa and amaranth seeds is shown in Table 3. The evaluated treatments showed statistically significant differences (p≤0.05) in total phenolic content, with an increase from 3366.91 to 6940.59 mg GAE/kg for Q-NG and Q-G, respectively and from 796.94 to 6330.91 mg GAE/kg for A-NG and A-G, respectively.  Similarly, total flavonoid content increased (p≤0.05), with values of 160.16, 620.13, 851.24 and 1141.19 mg CE/kg for A-NG, Q-NG, Q-G and A-G, respectively. Condensed tannin content showed the same increasing trend across treatments, with values of 443.94, 2435.28, 5044.34 and 8064.69 mg CE/kg for A-NG, Q-NG, A-G and Q-G, respectively.


       
Phenolic compounds, such as phenolic acids and flavonoids, increase significantly during germination due to enzymatic activity and metabolic processes (Günal-Köroğlu et al., 2025). The hydrolysis of cell wall polymers as a result of germination produces an increase in free phenolic compounds and, consequently, an increase in their availability (Borges-Martínez et al., 2022).
       
Ramos-Pacheco et al. (2024) reported values of 288.6 mg GAE/kg in quinoa samples (Choclito ecotype) after 72 h of germination, with initial values of 236.4 mg GAE/kg dry sample. On the other hand, Younis et al., (2024) reported initial phenolic compound contents in quinoa seeds of 2525.7 mg GAE/kg dry sample, which decreased to 2407.1 mg GAE/kg after roasting treatment (120°C, 15 min) and further declined to 1377.0 mg GAE/kg after germination (96-120 h). According to Karaman et al., (2024), the phenolic compound content in sprouts depends on factors such as crop type, germination conditions and extraction method.
       
Regarding total flavonoids, Li et al., (2022) reported the highest total flavonoid values in licorice (Glycyrrhiza uralensis Fischer) intended for beverage preparation, reaching 74.7 mg CE/kg under roasting conditions of 180°C for 20 min. Similarly, Aung et al., (2022) reported values of 800 mg CE/kg in wheat, representing the highest value obtained after germination treatment (17.6°C, 46.18 h), drying (45°C, 16 h) and roasting (180°C, 50 min). The authors attributed this increase to the degradation of internal tissues and the subsequent release of bound phenolic compounds and flavonoids during roasting.
 
Antioxidant capacity in free fractions
 
The antioxidant capacity in the free extracts of non-germinated and germinated quinoa and amaranth seeds is shown in Table 4. Statistically significant differences (p≤0.05) were observed in the antioxidant capacity of the evaluated treatments using the previously described methods. For DPPH, the values were 2533.00, 12512.80, 24922.20 and 25351.50 µmol TE/kg for A-NG, Q-NG, Q-G and A-G, respectively. The values recorded for ABTS were 7196.40, 20935.60, 40224.70 and 41005.10 µmol TE/kg for A-NG, Q-NG, A-G and Q-G, respectively. Finally, the antioxidant capacity values obtained by FRAP were 5735.10, 22871.30, 42402.00 and 44327.60 µmol TE/kg for A-NG, Q-NG, Q-G and A-G, respectively.


       
Antioxidant capacity is primarily associated with phenolic compounds synthesized or released during germination. Due to their hydroxyl groups and double bonds, phenolic compounds neutralize free radicals as a result of their ability to donate electrons or hydrogen atoms (Woolfolk-Chávez et al., 2026).
       
Zhang et al., (2023) evaluated antioxidant capacity in black barley (Hordeum vulgare) under different treatments, including germination (28°C, 60 h). Their results showed higher antioxidant capacity than non-germinated grain, with DPPH values increasing from 57393.2 to 64086.9 µmol TE/kg, ABTS values reaching 36634.7 µmol TE/kg and FRAP values increasing from 32175.3 to 48832.4 µmol TE/kg.
       
On the other hand, Woolfolk-Chávez et al. (2026) reported values of 12700 µmol TE/kg for DPPH and 20490 µmol TE/kg for ABTS in germinated amaranth (Amaranthus hypochondriacus) samples (30°C, 72 h). Regarding FRAP, the authors reported values of 15580 µmol TE/kg after 48 h of germination at 30°C.
 
Phenolic compounds in bound fractions
 
The content of total phenolic compounds (mg GAE/kg), total flavonoids (mg CE/kg) and condensed tannins (mg CE/kg) in the bound extracts of roasted non-germinated and roasted germinated quinoa and amaranth seeds is shown in Table 5.


       
The contents of total phenolics, total flavonoids and condensed tannins were not significantly affected (p≥0.05) by the evaluated treatments. The recorded values for total phenolics were 389.42 mg GAE/kg in Q-NG, 348.76 mg GAE/kg in A-NG, 412.72 mg GAE/kg in Q-G and 372.34 mg GAE/kg in A-G. Regarding total flavonoids, the obtained values were 188.68, 263.58, 206.30 and 170.83 mg CE/kg for Q-NG, A-NG, Q-G and A-G, respectively.
       
Regarding to condensed tannins, although no significant differences were observed among treatments (p≥0.05), an increase was observed from 58.27 mg CE/kg in A-NG to 584.75 mg CE/kg in A-G, while the values in Q-NG and Q-G were 174.76 and 171.82 mg CE/kg, respectively.
       
The results obtained in this study showed a higher concentration of phenolic compounds in the free fraction than in the bound fraction. However, Bhinder et al., (2021) reported a higher content of phenolic compounds in the bound fraction (5380 mg GAE/kg dry sample) than in the free fraction (3050 mg GAE/kg dry sample) in germinated white quinoa samples (72 h, dried at 50±5°C for 24 h). Nevertheless, the difference between both fractions could already be observed in the raw sample, with free fraction values of 2390 mg GAE/kg, while the bound fraction values reached 4710 mg GAE/kg dry sample. This behavior may be attributed to both genotype and cultivation conditions (Schutte et al., 2024).
       
Conversely, Mohamed et al. (2024) reported a higher total phenolic content in the free fraction (16681.00 mg GAE/kg) than in the bound fraction (8222.00 mg GAE/kg) in black quinoa, observing an increase in both fractions after a roasting treatment (120°C, 30 min). In the free fraction, total phenolics slightly increased to 16722.00 mg GAE/kg, while in the bound fraction, they increased to 16153.00 mg GAE/kg. The same authors reported total flavonoid values in the free fraction increasing from 4910.00 to 5060.00 mg CE/kg. Likewise, the values in the bound fraction increased from 1401.00 to 2207.70 mg CE/kg.
       
In contrast, the results obtained in this study showed a decrease in both fractions after germination and subsequent roasting treatment. Phenolic compounds and flavonoids concentrated in the bound fraction are released during roasting due to the degradation of the cellular structure (Aung et al., 2022). However, applying even higher temperatures may reduce these compounds due to the thermal degradation of the phenolic compounds themselves (Schutte et al., 2024).
       
Similar to total flavonoids, condensed tannins also showed a decrease in content after germination, followed by roasting in the bound fraction. Thakur et al., (2021) reported the same trend, observing a decrease in tannin content from 0.065% to 0.044% after 72 h of germination (25°C, drying at 40°C for 24 h) in amaranth seeds and from 0.048% to 0.035% in quinoa seeds, attributing this decrease to the solubility of the compounds in water during the seed soaking process.
       
Processes such as roasting, steaming, among others, may improve the nutritional quality of quinoa and other pseudocereals or cereals by reducing the negative effects of tannins (Manzanilla-Valdez et al., 2024), as reported by Sharma and Gujral (2020), who observed a decrease from 3.01% to 1.13% (catechin equivalent, dry basis) after 48 h of germination in millet seeds and by Prashanth et al., (2024), who reported a range of 0.19 to 0.28 mg CE/g (dry basis) when evaluating millet (Pennisetum glaucum) after a hydrothermal treatment..
 
Antioxidant capacity in bound fractions
 
The antioxidant capacity in bound extracts of roasted non-germinated and roasted germinated quinoa and amaranth flours is shown in Table 6. The antioxidant capacity determined by DPPH, ABTS and FRAP did not show significant changes (p≥0.05) after the evaluated treatments. The antioxidant capacity of roasted quinoa seed flour (Q-NG) was 1823.26 µmol TE/kg, while 1622.21 µmol TE/kg was recorded after germination and roasting (Q-G). On the other hand, the values for A-NG and A-G were 1574.11 and 1563.53 µmol TE/kg, respectively.


       
The antioxidant capacity recorded by ABTS was 4960.50 µmol TE/kg in Q-NG and 4524.43 µmol TE/kg in Q-G. Meanwhile, the observed results in A-NG and A-G were 4262.85 µmol TE/kg and 4403.39 µmol TE/kg, respectively. On the other hand, the antioxidant capacity values determined by FRAP were 4717.71, 4869.93, 3907.56 and 4062.66 µmol TE/kg for Q-NG, Q-G, A-NG and A-G, respectively.
       
Authors such as Zhang et al., (2022) reported higher antioxidant capacity, as determined by DPPH and ABTS, in the bound fraction compared with the free fraction in red quinoa flour, which differs from the results obtained in this study. Bhinder et al., (2021) also reported higher average antioxidant capacity by DPPH in the bound fraction of quinoa (4290 µmol TE/kg) than in the free fraction (3610 µmol TE/kg), maintaining the same trend after a malting process (72 h germination and 24 h drying at 50°C), with values of 5290 µmol TE/kg in the bound fraction and 4740 µmol TE/kg in the free fraction. However, in black quinoa, they obtained higher antioxidant capacity in the free fraction (6900 µmol TE/kg) than in the bound fraction (5250 µmol TE/kg) under the same conditions.
       
The results of Zivković et al. (2021) showed an increasing trend in antioxidant capacity determined by DPPH and ABTS in the bound fraction of germinated buckwheat (8 h soaking, 96 h germination at 20°C), from 16580 µmol TE/kg dry weight to 32562 µmol TE/kg dry weight and from 23730 µmol TE/kg to 26569 µmol TE/kg, respectively.
       
The antioxidant capacity values determined by ABTS were higher than those determined by DPPH, suggesting greater reactivity of phenolic compounds with the ABTS radical. Similarly, Hu et al., (2017) reported higher antioxidant capacity determined by ABTS in the bound fraction compared with the free fraction in red rice (2101 and 749 µmol TE/kg, respectively). The antioxidant capacity of the bound fraction increased after germination (12 h soaking, 48 h germination at 30°C) to 2208 µmol TE/kg; however, it decreased to 306 µmol TE/kg in the free fraction.
       
The results were consistent with those reported by Ti et al., (2014) for germinated brown rice (48 h, 20°C), which obtained antioxidant capacity values determined by FRAP of 4215 µmol TE/kg dry weight. Conversely, Zhang et al., (2021) observed a decrease in antioxidant capacity determined by FRAP in roasted mung bean (Vigna radiata) previously soaked (25°C, 8 h), from 15260 µmol TE/kg to 7220 µmol TE/kg in the bound fraction after roasting treatment (150°C, 30 min), despite having initially presented higher values compared with the free fraction prior to roasting.
       
Taking into account the increasing in the consumption of plant-based beverages, but also, the color developed in flours from quinoa and amaranth by germination and roasted treatments, as well as, the content of protein, the levels of phenolic compounds and their antioxidant capacity, they are optimal raw materials for formulation of pseudocereals based functional beverages.

The proximate composition of quinoa and amaranth flours was affected by the roasting and germination treatments in moisture, ash and fat, which showed slight differences. Germination and roasting together affected the color parameters of the flours, showing lower values in parameter L* and higher values for parameters a*, b* and C*. In addition, germination and roasting together proved to be viable processes for enhancing bioactive compounds and their antioxidant capacity, due to the positive effect on the results of this study. The flours characteristics obtained make them good ingredients for the development of pseudocereals based functional beverages in the near future. 

The authors thank to Programa de Apoyo a la Publicación Científica en Revistas Indexadas en el Journal Citation Report (JCR) 2026 of the Universidad Autónoma de Nuevo León for covering the Article Processing Charge. Cyntia Valeria Rodríguez-Sánchez thanks to Secretaría de Ciencia, Humanidades, Tecnología e Innovación (SECIHTI) for the scholarship 4032898 granted.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.

The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the design of the study, data collection, analysis, decision to publish, or preparation of the manuscript.