**2.4 Color**

The surface color was measured on randomly selected tortilla and *masa* spots and was measured in triplicate using a Konica Minolta model CR-400 colorimeter (Konica Minolta Holdings, Inc., Japan). The color was expressed as L\*, a\* and b\* colorimetric coordinates in the CIELab scale, as in Ref. [26]. The hue angle (H), chroma (C) and change in color (ΔE) were calculated according to eqs. (1)–(3), respectively [27].

$$\mathbf{H} = \tan^{-1} \left( \mathbf{b}^\* \,/ \, \mathbf{a}^\* \right) \tag{1}$$

$$\mathbf{C} = \sqrt{\left(\mathbf{a}^\*\right)^2 + \left(\mathbf{b}^\*\right)^2} \tag{2}$$

$$
\Delta E = \sqrt{\left(\Delta L^2 + \Delta a^2 + \Delta b^2\right)} \tag{3}
$$

## **2.5 Texture**

The texture of tortillas was measured as a perforation test [28]. The test conditions were 50 mm distance from the puncture base, and the applied force was the necessary to cause the tortilla to break. The texture profile analysis (TPA) of *masa*s was

done following the procedure described in [29] to determine hardness, adhesiveness, cohesiveness, and springiness. Both texture analysis were done in triplicate, using a texturometer Shimadzu EZ-SX Texture Analyzer (Shimadzu Co., Japan) and the software used for data analysis was Trapezium X (Shimadzu Co., Japan).

### **2.6 Total phenolic content (TPC) and antioxidant capacity**

The extracts used for both TPC and antioxidant capacity were prepared by mixing 1 g of *masa* with 10 ml of distilled water and let to stand for 12 h. Next, samples were centrifuged at 1325 x g for 10 min. The three assays were measured using a UV-Vis spectrophotometer model Multiskan Sky Microplate (Thermo Fischer Scientific, USA). Total phenolic content (TPC) was measured using the Folin–Ciocalteu assay as in Ref. [30]. A gallic acid calibration curve (0–1000 mg/L) was prepared to calculate the TPC and the results were expressed as gallic acid equivalents (mg GAE/100 g of *masa*).

In order to quantify the antioxidant capacity, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) was used. The methodology for ABTS was done following the method in [31] and results were reported as % of inhibition and were calculated using the following eq. (4).

%inhibition initial absorbance final absor = (( − × bance / initial absorbance 100 ) ( )) (4)

The methodology used for Ferric Reducing Antioxidant Power Assay (FRAP) was the one described in [32]. The results were expressed as μmol Trolox equivalents (TE)/100 g of *masa*.

#### **2.7 Statistical analysis**

All tests were performed in triplicate and the results had a coefficient of variation (CV) < 5%. The results were analyzed using one-way ANOVA (α = 0.05) with Minitab 19 (Minitab, LLC, State College, PA, USA). The mean differences were determined using a Tukey's multi-comparison test (α = 0.05).
