Acceptability of Tortillas and Tamales Made with Nixtamalized Corn with Germinated Chia Flour ^†

Abstract

Corn, Zea mays, is an ancestral food, culturally included in different forms in the Guatemalan diet. The most common form is in tortillas and tamales, which makes them suitable for incorporating other ingredients that increase their nutrient content. A sensory study was conducted with the aim of determining whether the appearance and texture of the tortilla and tamale remain acceptable when adding germinated chia seed flour (Salvia hispanica L). Germination was carried out for one day at 20 °C; it was prepared as flour and mixed with nixtamalized corn flour in a ratio of 10:90 and enough water to mold the tortillas; for the tamale, the same proportion of corn flour and germinated chia flour was used, and water and 8.6 percent oil were added. The tortillas and tamales were prepared and cooked in a traditional way by experts. For the acceptability test, 52 consumers were recruited, who signed the informed consent and subsequently evaluated the appearance and texture using a five-point hedonic scale (1 = I like it very much, 5 = I dislike it very much). The results indicate that the average acceptability of the appearance of the tortilla is 1.2 and the texture is 1.8. The average acceptability of the appearance of the tamale is 1.9 and the texture is 1.19. When comparing the acceptability of the appearance and texture of both preparations, a significant difference was found (p < 0.05), with the appearance and texture of the tamale being more acceptable.

1. Introduction

The corn grain is one of the oldest known, approximately 7000 years old, and it originated from Central America and was an important food in the Mayan civilization. It has a role in religious beliefs and festivities [1].

This cereal is a pillar in the food security of Guatemalan families, especially those living in rural areas [2]. The seed can be consumed in the diet in the form of tortillas and tamales; however, corn contains a low protein content, approximately 8% [1]. On the other hand, the chia seed is consumed in the form of a whole seed as an ingredient in other preparations enriching the sensory characteristics of foods. Current research proposes that germination improves nutritional values in this seed, increasing the bioavailability of proteins by the action of proteases [3]. For this reason, it is intended to take advantage of the fact that corn tortillas and tamales are culturally consumed in Guatemala to incorporate germinated chia seeds and thus take advantage of their nutritional benefits; however, the sensory impact that these have on tortillas and tamales is unknown. The objective of this research was to determine if the appearance and texture of the corn tortilla and tamale remain acceptable when adding germinated chia seed flour.

2. Materials and Methods

2.1. Seeds and Corn Flour

Chia seeds (Salvia hispanica L.) and nixtamalized corn flour were used, obtained in local markets in Guatemala City.

2.2. Germination

Germination conditions were established as analyzed by Salgado et al. [4]. 450 g of seeds were used, which were disinfected with 96% ethanol; the mucilage was hydrated with 250 mL of distilled water. The seeds were then placed in aluminum trays where they were allowed to germinate for two days at 21 °C, with a light period of 12 h and a dark period of 12 h.

2.3. Preparation of Germinated Chia Flour

The trays with the sprouts were dried at 40 °C for 24 h in convection ovens (BOV V70F Biobase, Haan, Germany). The material was ground after drying in an ultracentrifugal mill (Mill ZM 200, Retsch^®, Wolfenbüttel, Germany) at 600 rpm. The flour was stored in hermetic conditions in properly labeled ziploc bags.

2.4. Preparation of Germinated Chia Flour

2.4.1. Tortillas

They were prepared by experts in a traditional way; each tortilla was made with 90 g of nixtamalized flour and 10 g of germinated chia flour. The ingredients were mixed with enough water to obtain dough, which was molded into a circular and flat shape by hand. The tortillas were cooked at high temperatures (170–212 °C) for three minutes (one and a half minutes per side) on an iron griddle, special for tortillas, and bathed with a layer of water and calcium hydroxide solution.

2.4.2. Tamales

Prepared with the same proportion of corn flour and germinated chia flour used in tortillas, however, in addition to water, 8.6% sunflower oil and 1% NaCl were added to the formulation. The ingredients were mixed until a dough was obtained, wrapped in corn leaves, previously washed and dried. Each tamale was cooked in an aluminum pot, submerged in water, for 30 min at a temperature of approximately 100 °C.

2.5. Selection of Judges for Sensory Analysis

Using a non-probabilistic sampling, 52 consumers of corn tortillas and tamales, over 18 years of age, were chosen, a criterion chosen based on knowledge in perceiving variability in aspects of texture and appearance of tamales and nixtamalized corn tortillas. The voluntary participation of the panelists was recorded by informed consent.

2.6. Sensory Analysis

The test was carried out in a single session. Each panelist was given a tortilla and a tamale with germinated chia flour on a transparent plate. Each judge was told to remain silent during the exercise and to taste the preparations once. They were then evaluated using a data collection form and a 5-category hedonic scale with ordinal responses. According to Ruiz Vásquez and Soriano Colchado [4], hedonic scales with different numbers of categories, from “I like it a lot”, “I neither like it nor dislike it”, to “I dislike it a lot”, are ideal for evaluating acceptability.

2.7. Statistical Analysis

The data were tabulated and processed in STATGRAPHICS Centurion XVIII. The descriptive categories on the hedonic scale were transformed into numerical scores such that 1 represents “I like it very much”, 2 “I like it”, 3 “I neither like it nor dislike it”, 4 “I dislike it”, and 5 “I dislike it very much”. The numerical scores for each attribute were analyzed using an analysis of variance (ANOVA) and its respective Fisher’s least significant difference (LSD) test. The criterion for the interpretation of means for texture and appearance was 0.0–2.0 acceptance, 2.1–2.9 interference, and 3.0–5.0 rejection.

3. Results

Table 1. Hedonic scale acceptability analysis for appearance and texture of tortillas and tamales with incorporated chia flour according to analysis of variance and their respective Fisher’s LSD test.

Appearance Attribute
Product	Tortilla	Tamale
Formulation	90:10	90:10
Mean ± SD	1.92 ± 0.82 a	1.58 ± 0.60 b
Sum of squares	3.11
Gl	1
Mean square	3.12
F-ratio	8.88
p	0.0044
Texture Attribute
Product	Tortilla	Tamale
Formulation	90:10	90:10
Mean (SD)	1.79 ± 0.68 a	1.19 ± 0.16 b
Sum of squares	9.24038
Gl	1
Mean square	9.24
F-ratio	30.88
p	1.00 × 10−6

Note: The formulation being 90:10 it would be 90% nixtamalized corn flour, 10% germinated chia flour. SD: standard deviation, Gl: degrees of freedom. Fisher’s significant difference (LSD) test indicates that there is a significant difference between the appearance and texture of the tamale and tortilla, p < 0.05. ^a,b The data with different literals indicate that there is a significant difference between them according to Fisher’s LSD test. Criteria: 0.0–2.0 acceptance, 2.1–2.9 interference and 3.0–5.0 rejection.

shows the analysis of variance with its corresponding Fisher LSD test, indicating that the acceptability in appearance and texture of the tortilla with a formulation of 90 g of flour and 10 g of germinated flour, measured by hedonic scale, is acceptable, presenting a mean of 1.92 (0.82 SD) for appearance and 1.79 (0.68 SD) for texture. As for the tamale made with the same proportion of corn flour and chia sprout flour, its acceptability in appearance and texture was also considered acceptable, presenting means of 1.58 (0.60 SD) and 1.19 (0.16 SD), respectively. Rejection was not present for either preparation; however, the tortilla was the one that obtained the lowest score in acceptability for both attributes.

The test determined that there was a significant difference (p < 0.05) between the evaluated appearance of the tortilla and the evaluated appearance of the tamale, with a degree of freedom of 1 and p = 0.0044, with the appearance of the latter being more acceptable. It was also determined, with 1 degree of freedom and p = 1.00 × 10⁻⁶, that for the tortilla and tamale pair, there was a significant difference in texture, with the tamale being more acceptable in this aspect than the tortilla.

Figure 1 shows in general terms the scores of the hedonic scale of acceptability for appearance, noting that the highest score in the two attributes was obtained by the tamale with 10 g of chia flour, according to the Tukey test. The same behavior is observed in Figure 2, where the highest score on the hedonic scale for the texture attribute was for the tamale.

4. Discussion

Salgado et al. [5] state that the scientific field still does not have extensive knowledge about the incorporation of sprouted chia in food products and that it has only been sensorially evaluated by Argüelles-López et al. [6] in two functional beverages, the first using a mixture of 70% extruded amaranth flour and 30% sprouted chia flour and the second with 70% sprouted amaranth flour and 30% sprouted chia flour. They obtained as a result a high acceptability (average of 83–85), corresponding to I like it a lot for both beverages. With this, it could be said then that sprouted chia seed improves in general terms the acceptability of products.

On the other hand, if we talk only about chia flour, the literature reports its use to improve the sensory properties of cereals such as wheat bread, cookies, and other flours [7]. In a study carried out by Rendon-Villalobos et al. [8], where they sensorially evaluated aspects of general acceptability, flavor, color, and aroma intensity of corn tortillas made with oil and supplemented with 5%, 10%, 15%, and 20% chia seed flour, they found that this did not alter the sensory properties of the tortillas.

Other authors found higher scores in general acceptability when tortillas made with sprouted whole wheat flour were made, concluding that these provide a better appearance and greater acceptability by the consumer [9]. The conclusions of these investigations can explain why tortillas and tamales with sprouted chia flour were acceptable in the general appearance of the product, as indicated in Table 1.

As for the acceptable result in texture of the tortillas and tamales made with sprouted chia seeds in the study, it can be compared with that obtained by Ghafoor et al. [10] since they obtained a high acceptability score, in the texture attribute, when 2.0% and 3.5% of chia flour are used in bread formulations with 75.0 or 80.5% quinoa flour.

The good score for texture is also demonstrated by other authors, where they mention that replacing rice and soy flours with 2.5% whole grain chia flour does not show significant differences in acceptability of texture and appearance compared to its control, that is, it does not alter the texture of the standard product [11].

The reason why the tamale with chia seed sprout flour is more preferred in appearance and texture than the tortilla with the same formulation is due to the use of oil; this is explained by Valenzuela et al. [12]. These authors mention that fat and oils, from a technological point of view, provide palatability and flavor to foods, to the point of giving a feeling of fullness. Rodríguez-Huezo et al. [3] conclude that hydrogenated vegetable shortening improves the textural and viscoelastic properties of tamales.

5. Conclusions

It is concluded that the tortilla and tamale made from nixtamalized corn with chia sprout flour were accepted in the attributes of appearance and texture, with the tamale being preferred over the tortilla in the sensory characteristics evaluated.