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Nixtamalization, a Mesoamerican technology to process maize at small-scale with great potential for improving the nutritional quality of maize based foods

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-"Nixtamalization" is the process of cooking maize grains in a lime solution, soaking and washing them, to obtain "nixtamal". Then it is stone-ground to obtain nixtamal dough or masa. A variety of products are obtained from it and tortilla (flat pancakes cooked in a griddle) is the most popular one. Although maize became a staple crop in numerous African countries, this process has not been commonly adopted in Africa. This paper reviews the technology of nixtamalization and highlights its benefits for possible adoption in African countries. This technology improves the quality of maize in different ways. From the technological point of view, lime-cooking improves the rheological properties of the dough (elasticity, resistance to tearing and cracking), conferring desired organoleptic characteristics. It significantly increases its calcium content, releases bound niacin and makes it available. Insoluble dietary fibre decreases from raw to nixtamalized maize; however the relatively high levels that remain in the dough are of nutritional significance. Total fat content decreases, but the lime cooking process does not cause changes in fatty acid distributions. Protein quality, as shown by higher protein efficiency ratios (PER) of nixtamal, compared to maize increases. In addition to these nutritional benefits, lime-cooking has also been found to reduce significantly the amount of mycotoxins that are present in maize. Fermentation of nixtamal further enhances its nutritional properties. Being simple and inexpensive, conditions to transfer this ancient technology to Africa could be assessed to contribute to improve the nutritional quality of maize based foods.
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735
Nixtamalization, a Mesoamerican technology to process
maize at small-scale with great potential for improving
the nutritional quality of maize based foods
Wacher Carmen
Departamento de Alimentos y Biotecnología, Facultad de Química, UNAM, 04510 México, D. F. México.
Corresponding author: wacher@servidor.unam.mx
- Abstract -
“Nixtamalization” is the process of cooking maize grains in a lime solution, soaking
and washing them, to obtain “nixtamal”. Then it is stone-ground to obtain nixtamal
dough or masa. A variety of products are obtained from it and tortilla (flat pancakes
cooked in a griddle) is the most popular one. Although maize became a staple crop in
numerous African countries, this process has not been commonly adopted in Africa.
This paper reviews the technology of nixtamalization and highlights its benefits for
possible adoption in African countries.
This technology improves the quality of maize in different ways. From the
technological point of view, lime-cooking improves the rheological properties of the
dough (elasticity, resistance to tearing and cracking), conferring desired organoleptic
characteristics. It significantly increases its calcium content, releases bound niacin and
makes it available. Insoluble dietary fibre decreases from raw to nixtamalized maize;
however the relatively high levels that remain in the dough are of nutritional
significance. Total fat content decreases, but the lime cooking process does not cause
changes in fatty acid distributions. Protein quality, as shown by higher protein
efficiency ratios (PER) of nixtamal, compared to maize increases. In addition to these
nutritional benefits, lime-cooking has also been found to reduce significantly the
amount of mycotoxins that are present in maize. Fermentation of nixtamal further
enhances its nutritional properties. Being simple and inexpensive, conditions to
transfer this ancient technology to Africa could be assessed to contribute to improve
the nutritional quality of maize based foods.
Key words: Maize – Nixtamal.
_________________________
2ème Atelier international / 2nd International Workshop
Voies alimentaires d’amélioration des situations nutritionnelles
Food-based approaches for a healthy nutrition
Ouagadougou, 23-28 / 11 / 2003
Small scale industrial food production and fortification
736
- Résumé -
La nixtamalisation: un procédé mésoaméricain de
transformation du maïs à petite échelle présentant un
grand potentiel pour l’amélioration de la qualité
nutritionnelle d’aliments à base de maïs
La Méso-Amérique est fort probablement le berceau du maïs où il fut domestiqué et
devint un aliment de base. Au Mexique, le maïs représente la moitié des aliments
consommés et contribue à environ 50% des ingérés énergétiques, cette proportion
étant supérieure pour les populations à bas revenus.
La nixtamalisation est le procédé qui consiste à cuire les grains de maïs dans une
solution de chaux, à les tremper et à les laver pour obtenir le «nixtamal». Il est ensuite
broyé pour obtenir une pâte de «nixtamal» ou masa. De nombreux produits peuvent
en être dérivés dont la tortilla (fine galette cuite sur une plaque chauffée) qui est le
plus populaire. Bien que le maïs soit aussi devenu un aliment de base dans de
nombreux pays africains, ce procédé n’a pas été communément adopté en Afrique.
Cette technologie améliore la qualité du maïs de différentes façons. D’un point de vue
technologique, la cuisson à la chaux facilite l’élimination du péricarpe et l’hydrolyse
alcaline libère des gommes du péricarpe et saponifie les lipides du germe, ce qui
améliore les propriétés rhéologiques de la pâte (élasticité, résistance au déchirement
et au craquelage). La cuisson altère la structure cristalline de l’amidon, et la
réassociation des molécules constitutives de l’amidon durant le trempage est
importante pour développer les propriétés rhéologiques de la pâte de nixtamal.
L’intensité de la couleur, l’odeur et la flaveur sont affectées par la chaux, conférant
ainsi des propriétés organoleptiques désirées. La teneur en calcium est
significativement augmentée, ce qui est important car les apports de calcium par les
produits laitiers sont limités dans les pays en développement en raison de leurs coûts
et des problèmes liés à l’intolérance au lactose. Le traitement alcalin libère la niacine
et la rend disponible, c’est la raison pour laquelle les civilisations pré-colombiennes ne
souffraient pas de pellagre. La teneur en fibres insolubles diminue du maïs brut au
maïs nixtamalisé; toutefois les niveaux relativement élevés encore présents dans la
pâte sont encore d’intérêt nutritionnel. La teneur totale en lipides diminue, mais la
cuisson alcaline n’altère pas la distribution en acides gras. Les protéines du maïs sont
de mauvaise qualité à cause de leur concentration limitée en lysine et tryptophane. La
nixtamalisation améliore la qualité des protéines, comme l’indique la valeur plus
élevée du coefficient d’efficacité protéique (CEP) dans le nixtamal que dans le maïs.
Outre ces bénéfices nutritionnels, il a été aussi montré que la cuisson à la chaux
réduit significativement la quantité de mycotoxines présentes dans le maïs.
La fermentation du nixtamal améliore ses propriétés nutritionnelles. La fermentation
naturelle d’une pâte de nixtamal pour obtenir du pozol (une boisson préparée par
suspension de la pâte fermentée dans de l’eau) entraîne une amélioration de la
qualité des protéines. Dans la mesure où elle est simple et peu coûteuse, il semble
intéressant d’étudier les conditions du transfert de cette ancienne technologie en vue
d’améliorer la qualité nutritionnelle des aliments à base de maïs.
Mots-clés: Maïs – Nixtamal.
_________________________
Production et fortification dans les petites industries agroalimentaires
737
INTRODUCTION
Mesoamerica (a region from Northern Mexico to Honduras and Nicaragua) is very
likely the origin of maize1. It was cultivated throughout the American continent, but it
was only consumed as the main food by the Mesoamerican cultures and at the
Southeast of the United States2. Maize is capable of adapting to the most diverse
ecological conditions, but is not capable of self-reproduction, so it depends on man to
perpetuate. It is Mesoamerica where it was domesticated and consumed as a staple
food1. Maize was also consumed in South America; however its role was never as
important as in Mesoamerica2. In Mexico, half of the total volume of food that is
consumed is maize, which provides approximately 50 percent of the energy intake and
this proportion is even greater for lower income groups. A great culinary tradition
includes about 605 different foods made with maize3.
Maize has several nutritional limitations, especially the quantity and quality of its
essential amino acids and niacin4. It is thought2 that unless it is prepared by specific
techniques, its nutritional value is marginal and any human population that depends
on it as a major staple would suffer some degree of malnutrition. Alkali cooking was
the main technique used to improve its nutritional value.
Presently, alkaline cooking or “nixtamalization” is widely used in Mexico and Central
America to process maize. The traditional process, which is still widely used, consists
of cooking maize grains in a lime solution, soaking for 8 to 16 hours and washing them
by hand to remove the pericarp. This nixtamal is then stone-ground to obtain nixtamal
dough or masa. A variety of products (tortilla chips, tamales, tostadas, tacos,
enchiladas, panuchos, sopes, atoles, etc.) are obtained from it and tortilla (flat
pancakes cooked in a griddle) is the most popular one (figure 1). According to
Paredes-López and Saharópulos5, in rural areas tortillas provide 50% of the proteins
and 70% of de calories consumed daily.
Figure 1: Tortilla baking at San Cristóbal de las Casas, Chiapas, Mexico.
Small scale industrial food production and fortification
738
In the American continent, the societies that cultivate and consume large amounts of
maize, use the alkali treatment as a way of softening the outer kernel2. The alkali used
for cooking can include lime (Ca(OH)2), wood ashes (KOH) and lye (NaOH). Lime use
is restricted to Mesoamerica; North American producers use wood ashes and it is not
used in South America, except for one community in Venezuela2. Although maize
became a staple crop in numerous African countries, this process has not been
commonly adopted in Africa.
Nixtamalization improves the quality of maize in different ways:
CHANGES IN THE MICROSTRUCTURE OF MAIZE DURING NIXTAMALIZATION
From the technological point of view, lime-cooking alters the microstructure of the
outermost layers of maize pericarp, which shows a corrugated-like structure5. Surface
materials dissolve partially and this facilitates pericarp removal during washing. The
aleurone layer remains attached to the endosperm; it behaves as a semi-permeable
envelope and might contribute to reduce protein losses. Most of the germ is retained
during nixtamal and tortilla making process and contributes to the overall nutritional
properties of the product. Boiling in lime causes removal of starch granules, so that
the soft (inner) endosperm is greatly altered: starch arrangement becomes irregular
and some fibrils connect the dispersed starch granules5. Important structural
alterations, caused by heat denaturation of proteins, cross-linkages produced by
unusual aminoacids and disruption of the tertiary structure of proteins occur. The
endosperm proteins remain attached to the starch granules; lime cooking changes the
physical appearance of protein bodies6. Improved digestibility of nixtamal proteins may
be due to a better accessibility to them caused by starch gelatinization and changes in
the protein matrix5.
LIME COOKING ALTERATIONS THAT RESULT IN TECHNOLOGICAL IMPROVE-
MENTS
Alkaline cooking and the steeping step cause water and calcium to be taken up by
the grain7. The role of lime is important, as it allows faster water absorption and
distribution throughout the grain components and it modifies the outer layers, so that
the pericarp fraction becomes gummy and sticky7. The alkaline treatment degrades
and solubilizes cell wall components and this facilitates pericarp removal. Alkaline
hydrolysis releases gums from the pericarp and saponified lipids from the germ that
improve the rheological properties of the dough (elasticity, resistance to tearing and
cracking). Alkali-soluble non-cellulosic wall polysaccharides (mainly arabinoxylan)
show interesting functional properties as adhesives, thickeners, stabilizers, emulsifiers
and film formers7. According to these authors, the presence of germ, which is not lost
during nixtamalization, gives more machinability to the masa, with a higher tolerance
to mixing and less susceptibility to breakdown. So, the traditional process results in
masa with desirable properties of cohesiveness and adhesiveness. This is attributed
to swelling of starch granules, to the presence of fibre gums from the nixtamalized
pericarp and of saponified lipids from the germ.
During steeping, the grains absorb water and are softened due to the distribution of
water7. Cooking alters starch crystallinity and reassociation of starch molecules during
steeping is important to develop the rheological properties of nixtamal dough.
Grinding disrupts the grain structure, dispersing cellular components and starch
polymers. Masa can be considered to be a network of solubilized starch polymers with
dispersed, uncooked and swollen starch granules, cell fragments and lipids8.
Production et fortification dans les petites industries agroalimentaires
739
According to Gómez et al.9, swollen and partially gelatinized starch granules in a
network of dispersed starch polymers, allows tortilla shaping during kneading and gas
retention (puffing) during baking. Protein bodies swell, lose their shape and in some
cases are physically destroyed during baking or drying6. After baking, starch granules
and endosperm pieces are glued together by amylose, protein, lipids and cell wall
components. During the 45-60 sec of baking time, water evaporates from the tortilla
surface. Granules on the surface are partially gelatinized and more dehydrated; those
in the middle are more gelatinized9. This results in stretchable and elastic tortillas that
are resistant to tearing and cracking.
Organoleptic changes brought about by nixtamalization are probably the most
important for consumers. Colour intensity, smell and flavour are affected by lime,
conferring desired organoleptic characteristics. Lime affects tortilla colour and its
intensity is related to carotenoid pigments, flavonoids and pH. The development of
colour during nixtamalization is more complex, as calcium hydroxide reacts with
different pigments10. Tortilla flavour is enhanced by Maillard browning reactions
occurring between reducing sugars and peptides and unsaturated fatty acids.
LIME-COOKING ALTERATIONS THAT RESULT IN NUTRITIONAL IMPROVEMENTS
Dry matter losses occur during lime cooking and steeping and this is a drawback of
nixtamalization. Total dry matter losses in commercially processed corn have been
reported to be 2.8 to 10.7% between cooking and steeping and 1.6-2.0% during
washing. The average composition of the suspended solids in “nejayote” (the cooking,
steeping and washing water, which is discarded) was: 64% non-starch
polysaccharides (mainly pericarp fiber), 20% starch and 1.4% solids washing11.
However, the alkaline process induces some significant favourable compositional
changes in maize:
Changes in protein content and quality
According to Bressani et al.12, the protein content of raw maize varies from 9.4 to
10.2%, of cooked maize from 10.0 to 10.6% and of tortillas from 9.5 to 11.0%.
Regarding lysine and tryptophan, which are the two most limiting aminoacids in maize,
the same authors reported that lysine content does not change significantly due to
processing (158-166 mg/g N in raw maize to 152-165 mg/g N in cooked maize, to 145-
175 mg/ g N in tortilla), but lime cooking and tortilla baking decrease tryptophan
content in maize from an average value of 38 mg/g of nitrogen in raw maize to 26
mg/g of N in tortillas. Another report2, indicates that there are considerable losses of
total nitrogen during the cooking process, but the relative amount of lysine in nixtamal
is increased 2.8 times, tryptophan is increased slightly and the isoleucine/leucine ratio
increases 1.8 times.
Regarding protein quality, Bressani et al.12 showed that rats fed a casein diet showed
weight gain, food intake and protein efficiency ratio (PER) significantly greater than
those for rats fed diets on raw and processed maize, confirming other reports on the
low quality of maize protein. However, the beneficial effect of lime cooking was
demonstrated, as animals consuming diets made from maize dough and tortillas
showed a weight gain and PER significantly (p < 0.01) greater than animals fed raw
maize diets.
Nixtamalization alters the solubility patterns of maize proteins. Lime cooking and
tortilla baking decrease the solubility of albumins and globulins (salt-water-soluble)
and prolamins (alcohol-soluble). This alters the molecular weight distribution of the
different protein fractions13. Bressani and Scrimshaw14 showed that cooking with lime
Small scale industrial food production and fortification
740
selectively enhances the nutritional quality of corn and that this probably results from a
relative decrease in the solubility of the zein portion (deficient in lysine and tryptophan)
of the corn proteins. This procedure selectively enhances the quality of the corn
protein that is available for enzymatic digestion.
Minerals
One of the most important contributions of nixtamalization is the increase in the
calcium content of tortillas. Serna-Saldívar et al.13 reported it increases 750%, which is
over 85% available15. This is relevant, as calcium intake from dairy products in
developing countries is limited by their high cost and problems associated with lactose
intolerance. Low calcium intake also causes osteoporosis, which affects mainly post-
and premenopausic women and elderly men. Nixtamalization also improves the
calcium/phosphorous ratio16. Martínez-Flores et al.17 studied the effect of calcium
absorption on physical properties and composition of rat femurs, comparing rats fed
with raw whole corn (RC), tortillas made from extruded masa with 0.25% lime content
(TEWL) and without lime (TE), and nixtamal tortillas (NT). The femurs of rats fed with
TEWL and NT were heavier, thicker, and longer, showed greater crystallinity and were
more resistant to fracture than the femurs of rats fed with RC and TE.
Phytic acid (myo-inositol hexaphospohoric acid), which reduces the bioavailability of
minerals, is found in relatively high concentrations in the germ (which is not eliminated
during nixtamalization). This is reduced from 8% (when low calcium concentration,
0.4%, is used to nixtamalize maize) to 30-45% (when high, 1.2% calcium
concentration is used). This reduction can be attributed to its lability to heat16. The
same authors reported that the amount of calcium in nixtamal is considerably greater
than the amount of phytic acid in the grain, so that this could be easily saturated by
calcium. This would prevent iron from binding to it and be available for absorption.
They showed that higher calcium concentrations used for nixtamalization led to higher
increments in ionizable iron. Soaking time did not affect these parameters.
Bressani et al.18 evaluated the composition of tortillas made by 5 different families and
the maize used to prepare them. Besides the increase in calcium content (from 48.3 ±
12.3 in maize to 216.6 ± 41.5 in tortilla), Ca:P balance improved and Fe (4.8 ± 1.9 in
maize to 7.0 ± 4.8 in tortilla), Cu (1.3 ± 0.2 in maize to 2.0 ± 0.5 in tortilla) and
Zn (4.6 ± 1.2 in maize to 5.4 ± 0.4 in tortilla) concentrations increased. They proposed
these minerals come from the lime or from the containers used to nixtamalize maize.
Vitamins
Maize is deficient in niacin, so a population whose diet consists mainly on maize
would be likely to develop pellagra if other dietary constituents were not present2. The
alkaline treatment releases bound niacin and makes it available19; this is the reason
why pre-Columbian civilizations did not suffer pellagra. On the other hand, Cravioto et
al.20 reported small losses of thiamin, riboflavin and niacin and a 40% loss in yellow
corn tortillas carotene during nixtamalization.
Dietary fiber and fat
The nixtamalization process helps to eliminate the pericarp, so insoluble dietary fiber
decreases from raw to nixtamalized maize; however the relatively high levels that
remain in the dough are of nutritional significance. According to Bressani et al.12, who
studied chemical changes during rural tortilla production in Guatemala, dietary fiber of
nixtamal dough (9.3 - 9.6%) is lower than that of raw maize (12.2 - 12.8%); however
total dietary fiber content of tortillas is higher (10.3 - 11.7%), possibly due to the
development of insoluble compounds when the maize dough is placed in the hot plate
Production et fortification dans les petites industries agroalimentaires
741
to bake tortilla. The same authors reported that total fat content decreases from 4.7%
(w/w) in raw maize to 2.8 (w/w) in tortillas, but the lime cooking process does not
cause changes in fatty acid distributions.
Mycotoxins
The maize grain is frequently invaded by moulds of the genera Aspergillus, Fusarium
and Penicillium. In addition to the nutritional benefits mentioned earlier, lime-cooking
has also been found to reduce significantly the amount of mycotoxins that are present
in maize21,22. Fusarium verticillioides and Fusarium proliferatum are capable of
producing fumonisins and frequently found in corn. Apart from causing animal
diseases, human esophageal squamous cell carcinoma has been linked with
consumption of fumonisin-contaminated corn. Dombrink-Kurtzman et al.21 reported
that tortillas made with naturally contaminated maize contained 18.5% of the initial
concentration.
The traditional nixtamalization process has been reported to reduce levels of aflatoxin
B1 by 94% and aflatoxin M1 by 90%22.
INDUSTRIALIZATION OF TORTILLAS
Tortilla elaboration has gone beyond the home-made procedure to become an
artisanal process, with small "nixtamal mills" and "tortillerías". About 100,000
establishments are dedicated to tortilla elaboration1. These are small family-type
shops, where most of the population goes everyday to get fresh tortillas. These places
are very important, because of the high preference for ready-made tortillas. Important
agroindustries have also developed to obtain dry nixtamal flour. In 1996, Torres
Salcido23 reported about 34% of tortillas was made in Mexico from nixtamal flour.
Although the use of maize in Mexican cooking has received international recognition,
its daily consumption for an important part of the population is a monotonous diet of
tortillas and beans, which does not provide enough nutrients for a good physical and
mental development. Fortification of foods that are generally consumed, as tortillas,
can benefit most of the undernourished population. In 1997 Mexico established the
addition of 7 micronutrients in nixtamal flour: vitamins A and C, riboflavin, niacin, folic
acid, iron and zinc, to counteract deficiencies in the diet of the rural population
especially. For this reason, fortified nixtamal flour is distributed by the government at
subsidized prices24.
NIXTAMAL FERMENTATION
Fermentation of nixtamal further enhances its nutritional properties. According to
Cravioto et al.25, after natural fermentation of nixtamal dough to obtain pozol (a
beverage prepared by suspending in water this acidified dough), riboflavin, niacin and
protein concentrations increase. Tryptophan and lysine concentrations increased from
0.46 g/100 g protein in maize to 0.71 g/100g in pozol and 3.05 g/100 g in maize to
3.96 g/100 g in pozol, respectively. The calculated biological value of pozol proteins
was 66.75%, compared to that of maize (55.60). In accordance with this, protein
efficiency ratio values for pozol and maize were 1.52 and 1.05 weight increase of
rats/g consumed protein, respectively.
Small scale industrial food production and fortification
742
CONCLUSION
The quality of maize is greatly improved by the ancient technology of nixtamalization.
It induces favourable modifications in its organoleptic attributes, rheological properties
and nutritional value. Being simple and inexpensive, conditions to promote the use of
this ancient technology to Africa could be assessed to contribute to improve the
nutritional quality of maize based foods. Furthermore, it would be interesting to
investigate if such a technology could apply for some other cereals (e.g. sorghum)
widely consumed in Africa.
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... Unfortunately, solely consuming corn as principal part of the diet has been partnered with issues of malnutrition, particularly in children (Katz et al., 1974;Maya-Cortes et al., 2010). Still, it cannot be denied that corn being a major staple did not pose any threat in providing proper nutrition in other countries, such as in Mexico (Wacher, 2003). Thus, it has been hypothesized that there must be a difference in the way corn is normally consumed or prepared in the Philippines as compared to other countries which might be the reason why Filipinos have not yet maximized the full nutritional potential and benefited from consumption of Philippine corn. ...
... Nixtamalization, a well-known pre-treatment technique in the tortilla industry, is an ancient method of processing corn and is widely used in various countries around the world, especially in Central America (Wacher, 2003). This process is said to enhance the nutritional value of maize by improving protein quality, increasing calcium and niacin bioavailability, and reducing phytic acid levels, thus also increasing iron digestibility and biovailability (Suri and Tanumihardjo, 2016). ...
... This process is said to enhance the nutritional value of maize by improving protein quality, increasing calcium and niacin bioavailability, and reducing phytic acid levels, thus also increasing iron digestibility and biovailability (Suri and Tanumihardjo, 2016). According to Wacher (2003), cooking maize in alkaline solution softens the kernels and alters its grain structure, thereby releasing bound nutrients to make them more available for use by the body upon consumption. To date, there are three types of nixtamalization processes being used, namely, traditional, classic, and ecological. ...
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Nixtamalization is an ancient method of processing corn that is said to enhance the nutritional value of maize by improving protein quality, increasing calcium and niacin bioavailability, and reducing phytic acid levels, thus increasing iron digestibility and biovailability. The main objective of this study was to determine the effect of different nixtamalization processes on the physicochemical and nutritional properties of quality protein maize (QPM) flour and evaluate its potential and acceptability as a flour substitute in Philippine salt bread baking, determined through sensory analysis. Three processes of nixtamalization were employed, namely, traditional, classic, and ecological. Nixtamalized QPM flours, combined with wheat flour in 30:70 ratio, were used in the product development and sensory evaluation of Philippine salt bread. Results revealed that nixtamalization contributed significantly in the pH, color, and particle size of nixtamalized QPM flours. There was a significant increase (P ≤0.05) in the moisture, crude protein, crude fiber, crude ash, calcium, iron, niacin, lysine, tryptophan, total starch, amylose, amylopectin, resistant starch, and soluble fiber contents and a significant decrease in the crude fat, nitrogen-free extract (NFE), phytate, and insoluble fiber contents of QPM flours after nixtamalization. No significant difference was found in the zinc and total dietary fiber contents among the samples. The Philippine salt bread produced using nixtamalized QPM flours had a high overall acceptability based on two-step sensory analysis. QPM is greatly improved by the ancient technology of nixtamalization and nixtamalized QPM flour showed desirable contributions in terms of the nutritional value and sensory attributes of Philippine salt bread when used as a flour substitute or blend.
... This process has been widely used for the treatment of many grainssuch as sorghum (Johnson et al., 2010) density, starch properties (thermal, pasting, and crystallinity, barley (Prakash et al., 2015), pearl millet (Ocheme, Oludamilola and Gladys, 2010), etc for the removal of their pericarp, thereby resulting in better pasting properties of the grain (Sefa-Dedeh et al., 2004). The agents used for the treatment are lime (Ca(OH) 2 ), wood ashes (KOH) and lye (NaOH) (Carmen, 2003). In addition, nixtamalization finds a wide application in the food industry (Rajeswari et al., 2015) (Santiago-Ramos et al., 2018). ...
... The role of lime is important, as it allows faster water absorption and distribution throughout the grain components. Similar results were shown by (Carmen, 2003) (Rajeswari et al., 2015) (Salazar et al., 2014). ...
... The process has been used, particularly for maize, to reduce the levels of mycotoxins. It has shown to reduce the content of aflatoxin B1 by 94% and aflatoxin M1 by 90% (Carmen, 2003). ...
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Nixtamalization is an age-old culinary technique used for Maize (corm) dated back to thousands of years back to the Meso-American era. It is a process in which dried grains are treated with alkaline agents by soaking them in alkaline solution (Doralinda 2010). Nixtamalization is an age-old culinary technique dated back to thousands of years back to the Meso-American era. It is a process in which dried grains are treated with alkaline agents by soaking them in alkaline solution. Alkaline agents mostly used for the treatment are lime, wood ash and lye. This treatment is widely used for the treatment of grains, especially maize in Mexico and Central America. Physical and chemicals changes occur during the treatment that help in increasing the nutritional value of the final product and there is a decrease in the anti-nutritional factors such as phytic acid and condensed tannins in case of cereals. Due to this, the bound niacin gets free as found in maize crops. Nixtamalizing the cereals is also found to be effective in increasing the sensorial characteristics of the final cooked product by increasing the crispiness of the finished product. The treatment has also shown positive effects in decreasing the acrylamide content in processed and fried foods made from nixtamalized treated grains.
... The aroma is formed during the frying process, in this process a milard reaction occurs which will form the flavor components. Carmen (2003) states that the aroma of frying products is obtained from the aroma of cooking oil (unsaturated fatty acids) and the aroma formed due to the Maillard reaction (reaction of reducing sugars with peptides) [17]. ...
... The aroma is formed during the frying process, in this process a milard reaction occurs which will form the flavor components. Carmen (2003) states that the aroma of frying products is obtained from the aroma of cooking oil (unsaturated fatty acids) and the aroma formed due to the Maillard reaction (reaction of reducing sugars with peptides) [17]. ...
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Fungal fermented foods, such as tempe, are nutritious, affordable, and a good source of protein. Nuggets are known as chicken-based ultra-processed food. However, Tempe as raw materials is rarely processed. The combination of Tempe nuggets and additional Okra could improve the nutritional content such as protein and fiber. The current study aimed to investigate the correlation between additional Okra in Tempe nuggets product and nutritional content, and sensory characteristics of fungal fermented food. Experimental design research was conducted from May to July 2019. A total of three treatments and three repetitions were carried out to develop this product including A1 (85% Okra and 15% Tempe flour), A2 (75% Okra and 25% Tempe flour), and A3 (65% Okra and 35% Tempe flour). Semi-trained panelists were selected to perform the sensory test. Protein and fiber of produce were assessed by the Kjeldahl method and the soxhlet method. The results indicated that Okra substitution was significantly liking of the color, taste, and aroma of the product (p<0.05), but not in texture indicator (p=0.06). The protein content of the product increased significantly in the A3 formulation. However, the fiber content had no significant difference between Tempe and Okra substitution (p=0.38). Okra has potential dietary food substitution to increase the protein of the fungal fermented food product. The combination formula of Tempe and Okra has a significant impact on the level of preference in color, flavor, and aroma of the Tempe nugget product. Future research is required to confirm this finding and contribute to the development of the Tempe nugget product.
... Tryptophan, a limiting essential amino acid (EAA), is a precursor for the synthesis of niacin in the human body (Carpenter, 1983;Friedman, 2018;Krehl, 1981;Park et al., 2000). Nixtamalization, a Mesoamerican ancient technology which involves the boiling of maize grains in alkaline solution (lime solution), is especially common in Mexico and most of Latin America, which aids in the liberation of proteins and also improves the bioavailability of calcium and niacin (Wacher, 2003). The Spanish explorers who took ...
... The nixtamal, as the maize is called once cooked this way, can cool in the cooking liquid for several hours, commonly overnight. Next, it is washed one or more times in water and milled into a dough known as masa [21]. It is thought that early nixtamalized maize was done with wood or seashell ashes [11,14]. ...
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Nixtamalization, which means cooking maize in alkaline water, is the central technique for the culinary use of maize in Mexico and Central America. Without this procedure, relying on maize as the basic starch staple is inadequate because of nutriment deficiencies. Mexico has more than 50 principal racial types of maize, and these differ in grain qualities that can require the adjustment of the nixtamalization process. Properties such as hardness and grain composition influence nixtamalization because they are related to the absorption of water that occurs during cooking and steeping. Some maize preparations, like tortillas and tostadas, can also require the adjustment of nixtamalization to obtain a high-quality foodstuff. We studied how women in three regions of the state of Chiapas, which differ in the prevalent maize race available, prepare their nixtamal and whether they make changes according to the type of food they prepare. Interviews of 30 women follow the measure of relevant variables when the women prepared nixtamal. We found that nixtamalization is adjusted for different grain hardnesses and for environmental conditions. Variations were found in the cooking time of the nixtamal, in the amount of time the nixtamal was steeped, and in a special process of double boiling of the nixtamal performed by some women for tostadas. Women that specialize in production for the market have developed variations preferred by consumers. As practiced by women in Chiapas, nixtamalization is a flexible technique that is adjusted for maize type and for food preparations.
... Pozol is suspended in water and consumed. A natural fermentation, without an intentional inoculum, but knowing that most microorganisms are introduced into the dough during the milling process, occurs [5]. Microbial groups, mainly lactic acid bacteria (LAB), enterobacteria, Bacillus spp., yeasts, and molds, have been detected [3,[6][7][8][9]. ...
Preprint
Pozol is a Mexican beverage prepared from fermented nixtamalized maize dough. To contribute to understanding its complex microbial ecology, the effect of inoculating on MRS-starch pure and mixed cultures of amylolytic Sii-25124 and non-amylolytic W. confusa 17, isolated from pozol, were studied on their interactions and fermentation parameters. These were compared with L. plantarum A6, an amylolytic strain isolated from cassava. Microbial growth, kinetic parameters, amylolytic activity, lactic acid production, and hydrolysis products from starch fermentation were measured. The population dynamics were followed by qPCR. L. plantarum A6 showed higher enzymatic activity, lactic acid, biomass production, and kinetic parameters than pozol LAB in pure cultures. Mixed culture of each pozol LAB with L. plantarum A6 showed a significant decrease in amylolytic activity, lactic acid yield, specific growth rate, and specific rate of amylase production. The interaction between Sii-25124 and W. confusa 17 increased the global maximum specific growth rate (µ), the lactic acid yield from starch (Ylac/s), lactic acid yield from biomass (Ylac/x), and specific rate of lactic acid production (qlac) by 15, 30, 30, and 40%, respectively compared with the pure culture of Sii-25124. Interactions between the two strains are essential for this fermentation.
... Nixtamalization generates significant changes in nutritional content and organoleptic characteristics of corn, such as: increases the calcium, iron, copper and zinc content, enhances niacin availability and lowers phytic acid content. [26] During nixtamalization, the phenolic content of the corn grain decreases [27,28] but baking the masa to obtain tortillas and frying tortillas has a small effect on the phenolic concentration and composition. [27] A slight increase of the free phenolics is observed when masa is transformed into tortillas and chips. ...
Article
Milpa is a traditional polyculture production system mainly composed of corn, beans and pumpkin, together with other edible plants. It represents an important food and nutrients supply, but also bioactive compounds source, such as phenols, anthocyanins, phytosterols, phytates, resistant starch, peptides, among others compounds that confer multiple health benefits. Therefore, the aim of this work was to gather the scientific evidence on the health effects of the bioactive compounds found in the plants that belong to the milpa. Although there are few studies that report the interaction between different biomolecules and crops in combination, as in meant to be at regular eating; evidence, here summarized, suggests that consumption of milpa vegetables has an active effect of biomolecules from these crops was found active, mainly on chronic non-communicable diseases. Thus, the main objective of this study was to summarize the scientific evidence on bioactive compounds found in the plants grown as part of the milpa and their health-related benefits.
... This work was supported by the Universidad Veracruzana through *Nixtamalization is a Mesoamerican process with great potential for improving the nutritional quality of maize-based foods. (Wacher, 2003.) ...
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In this case report, we present how we have approached the topic of the milpa in rural and indigenous contexts in Mexico as a basis for understanding the impacts of climate change, and as a traditional practice that can inform adaptation from a situated learning perspective in line with the curriculum. This research demonstrated effective ways to address climate change as a global problem that directly relates to local concerns and practices. This case used collaborative qualitative research to develop a training process in which teachers analyze learning progressions in their schools. The process included the design and implementation of relevant project materials.
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The HFE gene variant allele C282Y connected with hereditary hemochromatosis occurs at a frequency of about 10%–11% in Ireland, the highest known frequency in the modern global population. In this synthesis, we draw together an interdisciplinary literature to offer an agriculturally‐grounded, biocultural example of modern human adaptation and microevolution that addresses Ireland's comparatively high C282Y frequency. We argue that changing subsistence‐, diet‐, and nutrition‐related stressors framed under colonial governance played a role shaping the biology of Ireland's population historically, maintaining the C282Y variant. A population accustomed to challenges of poverty and difficult living conditions, the Irish fell under the influence of massive ecological stress with the fungus (Phytophthora infestans), the failed potato crops, and the Great Famine of 1845–52. From there, in the post‐Famine era, diet and nutrition altered further as the potato was exchanged for gluten‐rich wheaten bread and stewed black tea. With risks for iron deficiency anemia heightened by the cultural construction of diet and niche, an adaptive iron‐conserving advantage continued to be offered by the C282Y allele, influencing survival into the post‐Famine era. More recently, however, C282Y has been reframed as a potential risk in the context of contemporary, iron fortified diets.
Article
The nutritional composition of corn is relatively insufficient to sustain human growth and development. This study developed and characterized rice-nixtamalized corn blends to enhance the nutritional quality of rice-corn composites geared towards household consumption. Corn kernels of two Philippine corn varieties, IPB Var 6 (VK) and Lagkitan (LK), were nixtamalized using ecological method, processed into corn grits, and blended with locally available rice Sinandomeng. Out of the six rice-nixtamalized corn grits blends developed, three blends (30% VK, 70% LK, and 50% VK) were considered most acceptable based on sensory evaluation of consumer panelists. The blends required 210−290 mL cooking water and 20−25 minutes of cooking time. Microbial analysis showed that the blends had <1.0 × 10³ cfu/g yeast and mold count (YMC) after two months, indicating food safety upon storage. Both the IPB Var 6 and Lagkitan blends exhibited significant increase in calcium (2- to 3-folds), iron (4- to 7-folds), zinc, (1- to 2-folds), and phosphorus (1- to 2-folds) as compared to rice alone. Consuming 100 grams of the developed rice-nixtamalized corn grits blends can achieve an average healthy adult's daily calcium requirement by 4%, iron requirement by 7%, and as high as 35% zinc requirement.
Article
Alkaline cooking is an important aspect of corn preparation for human consumption. This review covers ingredients, traditional and current processing technologies, changes in physical and chemical properties during tortilla making, quality control, and the nutritional value of alkaline-cooked corn products. Subjects covered include products, shelf life, nuxtamalization, and others.
Article
Starches from corn and sorghum masas were solubilized in water and their molecular characteristics were studied with high‐performance, size‐exclusion chromatography (HPSEC). Rheological properties of masa (smoothness, plasticity and cohesiveness) that are developed during lime‐cooking, steeping and grinding of cereals were correlated to the starch solubility. Corn and sorghum were processed at different cooking times and grinding conditions; and the starch in masa was extracted with water at 85°C and 120°C for HPSEC analysis. Starches from corn and sorghum masas were affected in a similar way by the nixtamalization process; however, sorghum starch was more soluble than corn starch in flour and masa. Alkaline‐cooking, steeping and stone‐grinding did not depolymerize the cereal starch. All masas contained less than 10% soluble solids of which 30 to 50% was starch solubilized. Soluble solids increased with longer cooking time and finer grinding. About 50% of the insoluble starch, which remained in the particulate solids of masas was solubilized in water at 120°C. The remaining starch was indispersible because either the starch remained inside endosperm pieces or inside gelatinized and retrograded gels. Several granular and molecular forms of starch were present in masa as a result of partial gelatinization, i.e. uncooked, swollen, and annealed starch granules, and soluble and retrograded amylose. Retrogradationo f starch polymers occurred during steeping of cooked corn and during cooling of masa after grinding. Masa, a unique dough system, resulted from a network of starch polymers, uncooked and partially gelatinized starch granules supporting the rest of the kernel components into a continuous phase of water.
Article
Cereal Chem. 67(6):515-518 A total of eleven common maize cultivars and one variety of quality- results showed increases in Ca and Mg from raw maize to tortilla and protein maize (QPM) called "Nutricta" were processed into cooked maize a small decreases in Na and K. Total dietary fiber decreased from raw and tortillas by the method used in rural areas. Samples of raw and maize to masa, and then it increased in tortillas. Fatty acid composition cooked maize and their respective tortillas were analyzed for major nutrient was similar among the maize samples and distribution was not affected components, as well as for total dietary fiber, calcium, magnesium, sodium, by the lime cooking process. Protein quality was significantly higher and potassium. Four of the common maize samples, the QPM, and their (P < 0.03) in tortillas than in raw maize. In this respect QPM as a processing products were analyzed for fatty acid content, and were also raw grain and as tortillas was statistically significantly superior to common evaluated for protein quality. For both common maize and QPM the maize.
Article
Data show that the solubility of zein - alcohol-soluble fraction - is significantly decreased by the lime-heat treatment, which corn receives during the preparation of tortillas. Other nitrogen fractions also show a lower solubility but not to the same extent. The decreased solubility of zein should improve the biological value of the soluble proteins, as zein is the poorest of the corn proteins. The lime-heat treatment also increases the rate of release of most of the essential amino acids. These results suggest an explanation for the improved growth of rats fed tortillas as compared to corn.
Article
Scanning elecronmicroscopy (SEM) was used to study changes in corn kernel structure during the lime treatment of the tortilla making process. The outside surface of the alkali-treated kernels (nixtamal) showed substantial structural alteration, which facilitate its separation.The aleurone and some pericarp layers are retained in nixtamal. Most of the germ remains attached to the starchy endosperm, and greatly contributes to the nutritional quality of the product.The cell walls of the horny and floury endosperm appeared noticeably affected in the preparation of nixtamal. The functional and nutritional properties acquired by nixtamal might be related to the structural modification as shown by SEM.