Template:Chapter 9.12

9.12 - Nixtamalization to Improve Maize Nutrition

Ravjot Bhathha,University of Guelph, Canada

Suggested citation for this chapter.

Bhathha,R. (2022) Nixtamalization to Improve Maize Nutrition, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org

What is Nixtamalization

Maize grain is the third most important food crop in the world. In Mexico and Central America, about 300 g is consumed daily (Odjo et al., 2022). Maize is also a staple crop in Eastern and Southern Africa, with people consuming 52 - 328 g of maize grain daily (Ranum et al., 2014). The problem is that small scale farmers across these regions suffer from high rates of malnutrition (Ranum et al., 2014). Furthermore, many farmers experience post-harvest losses of maize due to mycotoxins in the seeds (Mohammed et al., 2023). Mycotoxins are deposited by fungi on maize grains, which can cause health issues for people and animals, including liver cancer. Since 2012, more aflatoxins have been found in East Africa and India compared to Mexico and Central America (Odjo et al., 2022). To reduce contamination from mycotoxins, post-harvest practices like nixtamalization are used.

Nixtamalization is a post-harvest practice used to decrease pathogen infestation and also increase the bioavailability of calcium and the quality of protein from maize grain (Odukoya, 2021). The maize is cooked and steeped in alkaline water. The traditional nixtamalization practice came from the Mayans (Escalante-Aburto, 2019). They used wood ashes and water to boil maize grain. It was later changed by the Aztecs to using lime and water. This was because lime was more effective in softening the pericarp and endosperm. The pericarp is the outer layer of the maize seed that increases the fibre content of the grain (Gutiérrez-Cortez et al., 2010), while the endosperm comprises the bulk of the seed and is where the starch, protein and oil are located. This softening process helped to make better quality masa and tortillas, as well as increasing their nutrition quality (Escalante-Aburto, 2019). In regards to nutritional quality, the nixtamalization process increases the bioavailability of niacin and protein (their accessibility to humans) from maize grain (Escalante-Aburto, 2019). Niacin, which is a B vitamin, helps convert convert food into energy (Escalante-Aburto, 2019).

Steps for Nixtamalizing Maize Grain

1) After removing the maize kernels, wash them in warm water. Clean it by hand. See Figure 1.

Figure 1: Washing maize

2) Calcium hydroxide, or slaked lime, is the best way to get optimal results from nixtamalization. The ratio of calcium hydroxide needed is 1 per cent compared to the total weight of the grain (Odukoya et. al, 2022).

3) To use the calcium hydroxide, which can be purchased from local markets, it is heated with hot water before it is used. Gloves do not need to be worn but care must be taken since this process uses boiling water. See Figure 2.

Figure 2: Adding calcium hydroxide to water

4) The maize kernels are mixed with water and lime and cooked in boiling water for about an hour. It depends on how hard the seeds are. The harder they are, the longer it needs to be cooked. They can be cooked using gas, fire, or a stove if available.

5) The maize seeds are steeped from 14 to 16 hours in the mixture.

6) After, the seeds are strained out and rinsed in clean water. The seeds after this process are now called “nixtamal” (Odjo et. al, 2022). See Figure 3.

Figure 3: Left - Kernels before nixtamalization; Right - After nixtamalization

Critical Analysis – Nutrient and Disease Changes

The two main nutritional changes in maize seed after nixtamalization is in calcium and protein, in addition to niacin (vitamin B3). Calcium hydroxide in the nixtamalization process improves calcium levels in humans and animals (Maureen et al., 2020). The increase in calcium helps with water retention in humans and animals that feed on maize (Maureen et al., 2020). However, compared to non-nixtamalized maize, the process potentially reduces total protein content in raw maize seeds by 1% depending on the alkaline concentration used (Maureen et al., 2020). Researchers did find that the protein amount is higher in the form of tortillas and dough than raw maize seeds (Maureen et al., 2020). Regions that consume high amounts of maize, such as SubSaharan Africa, have shown a decrease in pellagra disease after the adoption of nixtamalization. Pellagra disease can occur from a lack of vitamin B3 (Maureen et al., 2020). In terms of the impact of nixtamalization on mycotoxin reduction, in Uganda, researchers measured the impact of this method on two classes of mycotoxins: aflatoxins and fumonisins (Maureen et al., 2020). In Uganda, maize grain has low nutrient quality and a high infestation of mycotoxins (Maureen et al., 2020). The results showed that aflatoxins decreased by approximately 90 per cent and fumonisins by 80 per cent after nixtamalization. It also showed an increase in niacin availability (Maureen et al., 2020).

Cost Analysis of the Nixtamalization Process

Nixtamalization uses an alkaline mixture, which can easily be made at home. 80 per cent of Eastern Africa’s household income and food security comes from the production of maize and other cereals (Gachara, 2022). This method does not require any additional purchase of equipment or tools except for calcium hydroxide (slaked lime) or citrus lime. These products are diluted in water to make the alkaline mixture. If local markets do not have calcium hydroxide, the links below are to affordable powders that can be mixed with water. The prices varies based on the amount of calcium hydroxide needed for the farmer (Gachara, 2022).

Critical Analysis – Women’s Responsibilities

Results from a 2022 survey have shown that more than half of the respondents answered that maize processing is mainly performed by women (Lelea et al., 2022). Women are also more involved in the sale of maize flour after post-harvest processes (Lelea et al., 2022). Additionally, women are often the individuals who conduct the nixtamalization process and produce maize flour (masa). They play a significant role in providing food for their families and animals (Lelea et al., 2022). Women need to calculate how much maize to store for their families, animals, and the remainder for selling. They are the main decision makers for their crops. For these reasons, it is important for female farmers to learn the nixtamalization process. Nixtamalization would prevent crop losses from diseases, so female farmers would not need to manually remove diseased maize seeds (Gachara et al., 2022).

Conclusion

To conclude, smallholder farmers can benefit from using nixtamalization as an effective post-harvest processing method for maize grain. It is cost efficient, significantly decreases mycotoxins in the grain, and increases the bioavailability of nutrients. Regions in Mexico and Central America have used this method for centuries, and since it shows promising results, increasing the use of nixtamalization in Africa would be beneficial in preventing human and animal toxicity.

Further Readings

CIMMYT: https://www.cimmyt.org/news/what-is-nixtamalization/ Ministry of Agriculture - The Three Sisters: Optimizing the value and food potential of an ancestral indigenous crop system: https://agriculture.canada.ca/en/science/story-agricultural-science/scientific-achievements-agriculture/three-sisters-optimizing-value-and-food-potential-ancestral-indigenous-crop-system

YouTube Videos:

Nixtamalization in Mexico -- https://youtu.be/TIs3gjOPevw

Nixtamalization process -- https://youtu.be/Fbr1HFJ3ujY?si=Q7cwvc12b0sY3avy

Turning Maize into Masa -- https://youtu.be/bu4JB5E1e6I?si=j2UsBloywhbEFpGJ

Links to Purchase

Slaked Hydrated Lime Calcium Hydroxide • For 1-4 tons: US $100

Calcium Hydroxide Slaked Lime • US $50 per kilogram

Alkaline Protease Enzyme Powder • US $7.25 per kilogram

References

1. E. Gutiérrez-Cortez, I. Rojas-Molina, A. Rojas, J.L. Arjona, M.A. Cornejo-Villegas, Y. Zepeda-Benítez, R. Velázquez-Hernández, C. Ibarra-Alvarado, M.E. Rodríguez-García. (2010). Microstructural changes in the maize kernel pericarp during cooking stage in nixtamalization process, Journal of Cereal Science, 51(1), 81-88. https://doi.org/10.1016/j.jcs.2009.09.008.

2. Escalante-Aburto, A., Mariscal-Moreno, R. M., Santiago-Ramos, D., & Ponce-García, N. (2019). An Update of Different Nixtamalization Technologies, and Its Effects on Chemical Composition and Nutritional Value of Corn Tortillas. Food Reviews International, 36(5), 1–43. https://doi.org/10.1080/87559129.2019.1649693.

3. Gachara, G., Suleiman, R., El Kadili, S., Ait Barka, E., Kilima, B., & Lahlali, R. (2022). Drivers of Post-Harvest Aflatoxin Contamination: Evidence Gathered from Knowledge Disparities and Field Surveys of Maize Farmers in the Rift Valley Region of Kenya. Toxins, 14(9), 618. https://doi.org/10.3390/toxins14090618

4. Gutiérrez-Dorado, R., et. al. (2008). Technological and Nutritional Properties of Flours and Tortillas from Nixtamalized and Extruded Quality Protein Maize (Zea mays L.). Cereal Chemistry, 85(6), 808–816. https://doi.org/10.1094/CCHEM-85-6-0808.

5. Lelea, M. A., Garbaba, C. A., Guluma, A., & Hensel, O. (2022). Gendering post-harvest loss research: responsibilities of women and men to manage maize after harvest in southwestern Ethiopia. Food Security, 14(4), 951–963. https://doi.org/10.1007/s12571-022-01259-y

6. Maureen, N., N. Kaaya, A., Kauffman, J., Narrod, C., & Atukwase, A. (2020). Enhancing Nutritional Benefits and Reducing Mycotoxin Contamination of Maize through Nixtamalization. Journal of Biological Sciences (Faisalabad, Pakistan), 20(4), 153–162. https://doi.org/10.3923/jbs.2020.153.162

7. Mohammed, A., Seyoum, C., Yousuf, J., Mweetwa, A., Odera, J. A., Okello, D. K., Bekeko, Z., Tadessa, T., & Sulyok, M. (2023). Multi-mycotoxins analysis in post-harvest maize (Zea mays L.) grain from major producing areas of Ethiopia. World Mycotoxin Journal, 16(3), 261–272. https://doi.org/10.3920/WMJ2022.2829

8. Odjo, S., et. al. (2022). Occurrence and postharvest strategies to help mitigate aflatoxins and fumonisins in maize and their co-exposure to consumers in Mexico and Central America, Food Control, 138, 108968. https://doi.org/10.1016/j.foodcont.2022.108968.

9. Odukoya, J. O. (2021). Efficacy of selected processing techniques in mitigating mycotoxin contamination of maize and sorghum products in Sub-Saharan Africa. University of Johannesburg, South Africa. https://subzero.lib.uoguelph.ca/login?url=https://www.proquest.com/dissertations-theses/efficacy-selected-processing-techniques/docview/2724237017/se-2

10. Odukoya, J. O., De Saeger, S., De Boevre, M., Adegoke, G. O., Audenaert, K., Croubels, S., Antonissen, G., Odukoya, J. O., & Njobeh, P. B. (2022). Influence of nixtamalization cooking ingredients on the minerals composition of nixtamalized maize and sorghum. Journal of Cereal Science, 103, 103373. https://doi.org/10.1016/j.jcs.2021.103373

11. Ranum, P., Peña-Rosas, J. P., & Garcia-Casal, M. N. (2014). Global maize production, utilization, and consumption. Annals of the New York Academy of Sciences, 1312(1), 105–112. https://doi.org/10.1111/nyas.12396