Maize Testing

Maize is the world's most important crop and a cereal grain that was domesticated in Central America. It is one of the most adaptable and versatile emerging crops. Maize is known as the "Queen of Cereals" due to its high genetic yield potential. Maize is the only cereal crop that can be grown in a variety of seasons, ecologies, and applications. Other types of maize include regular yellow/white grain, sweet corn, baby corn, popcorn, waxy corn, high amylase corn, high oil corn, quality protein maize, and so on. Aside from that, maize is an important industrial raw material with a lot of potential for value addition. Maize is a member of the grass family Poaceae's tribe Maydeae. The name "Zea" was derived from an old Greek name for a type of food grass. The genus Zea contains four species, the most important of which is Zea mays L. The other Zea sp., teosinte, is primarily a wild grass native to Mexico and Central America.

Nutritional importance

Depending on the variety, maize may contain folic acid, provitamin A, Vitamin C, and a number of crucial B vitamins (i.e., precursor to vitamin A). Besides being high in potassium and calcium, maize is also a good source of phosphorus, magnesium, manganese, zinc, copper, iron, and selenium. While being very low in fat and sodium, maize is a great source of dietary fiber and protein (salt). Maize has a wide range of carotenoids, or various colored pigments, in both content and composition (see also Carotenoids). Notably, normal metabolic processes in the body convert the carotenoid beta-carotene (or provitamin A) to vitamin A. In particular for vision and as an antioxidant, vitamin A is crucial to human health. Therefore, maize can be particularly crucial for those who cannot always access fresh produce.

Types of maize

1.Dent corn (Zea mays var identata sturt): The most common type grown in South Africa. Dents form on the top of the kernel and are yellow or white in color. The depression or dent in the seed corn is caused by rapid drying and shrinkage. Of the soft starch variety.

2.Flint maize (Zea mays var indurate sturt): In India, it is widely grown and cultivated. The kernel's endosperm is soft and starchy in the center, and it is completely surrounded by a very hard outer layer. The top of the kernel is rounded. It could be white or yellow. Produced in Europe, Asia, Central and South America. Flint corn is a popular crop in India.

3.Popcorn (Zea mays var. verta sturt): It possesses exceptional characteristics. The kernels are small, but the endosperm is tough. When heated, the pressure buildup within the kernel causes an explosion, and the grain is turned out. Grains are consumed by humans and form the basis of popcorn confectionery. Its cultivation is mostly limited to the new world.

4.Corn flour (Zea mays var. anylacea sturt): It has a soft endosperm. The kernels are soft, and while all colors of corn are grown, white and blue are the most common. They have the shape of fruit kernels. Grown in the United States and South Africa.

5.Sweet corn (Zea mays var Saceharata sturt): Sugar and starch are the main components of the endosperm, which results in the sweetish taste of the kernels before maturity and wrinkled kernels after maturity. Green corn is picked up for canning and table use. Grown primarily in the northern half of the United States.

6.Pod corn (Zea mays var tunicate kulesh): Each kernel is contained within a pod. It is a primitive type of corn and thus has no significance.

7.Waxy corn (Zea mays var ceratina Kulesh): The endosperm of the kernel has a waxy appearance when cut or broken. It produces starch that is similar to tapioca starch and is used to make adhesive for articles.

Maize authentication

Maize adulteration can take many different forms, including using GMOs or less expensive varieties, mislabeling, or using maize to make more expensive cereals. Furthermore, when geographical origin claims are made, scammers can find cheaper or more easily accessible content and present it as local or genuine. From the perspective of food quality and safety, maize makes a great substrate for the growth of mycotoxins. It is crucial that appropriate steps be taken and established techniques for routine quality control and inspection. Mycotoxins like aflatoxin, vomitoxin (DON), fumonisin, zearalenone, and ochratoxin could be present in corn or maize. The maximum permitted levels of mycotoxins in maize are capped at 2 parts per billion (ppb) for aflatoxin B1, 750 ppb for deoxynivalenol (DON), 200 ppb for fumonisin, 3 ppb for ochratoxin A, and 60 ppb for zearalenone, according to international regulations. Eurofins provides screening and quantitative solutions for mycotoxin detection in the lab and on-site.

Regulations and standards:

Unless otherwise specified below, the Codex Alimentarius last edition standard applies to all aspects of the product, including packaging.

• The product must be fit for human consumption and of good, reasonable, and marketable quality.
• The Cartagena Protocol (a biosafety protocol added to the Convention on Biological Diversity) requires exporters/producers to indicate whether food items contain GMOs (Genetically Modified Organisms) or not
  
  

MAIZE (corn), GRAIN

General specifications applicable worldwide

MAIZE (corn), FLOUR

General specifications applicable worldwide

Specifications as per communication 2000/C312/01

On December 14, 2017, the FSSAI issued a notification on Food Safety and Standards (Food Product Standard and Food Additives) Amendment Regulation pertaining to standards for all pulses, whole and decorticated Pearl Millet grains, Degermed Maize flour and Maize Grit, Couscous, Tempe, Textured Soy Protein, Sago flour, Honey, Bee Wax & Royal Jelly, and Steviol glycoside. ⁽⁷)

• Degermed maize (corn) flour and maize (corn) grits have new standards. Degermed maize (corn) kernels of Zea mays L. are prepared into flour through a grinding process in which the kernels are fully mature, cleaned, and free from mould.
• Grain is removed from bran and germ after it has been sufficiently finely ground. The coarse pieces of the ground maize kernel can be separated, reground, and combined with the entire substance from which they were separated during preparation.
• Degermed maize (corn) grits are made from fully mature, cleaned, mold-free kernels of maize (corn), Zea mays, through a grinding process that reduces the grain's size to an appropriate level while removing the majority of the bran and germ.
• Degermed corn (maize) flour and grits must be free of unnatural tastes, odors, living insects, and filth (impurities of animal origin, including dead insects)
  
  

Testing methods

In research and industry, genetic markers, chromatographic and spectrometric techniques, lipidomics, and more sophisticated methods assessing changes at the molecular level have been used to determine maize varieties and genetic modification, verify geographical origin, detect contamination with toxins, and determine whether irradiation was used. More research is expected to focus on lowering the costs of these methods, simplifying them, and developing new improved methodologies to verify maize authenticity and detect fraud.

For geographical identification, cultivar differentiation, and authenticity regarding farming practices (organic vs. conventional) of rice samples, IRMS and ICPMS offer useful information. Similar to this, spectroscopic techniques demonstrated tremendous promise for cultivar discrimination and the veracity of organic rice. Omic analysis was particularly successful in identifying adulterants from rice samples, while DNA-based approaches offer useful insights in detecting adulteration and cultivar discrimination. The most popular unsupervised approaches for multivariate analysis are PCA and HCA, which are used to visualize and break down enormous data matrices into smaller variables before data processing. Additionally, the most popular supervised techniques used to handle the data acquired from various analytical techniques for rice authentication included ANN, KNN, LDA, PLS-DA, SIMCA, and SVM. ⁽⁸⁾

The following control methods are applicable as per the Codex Alimentarius

• ISO 6540 Maize moisture content determination (for milled grains and whole grains).
• ICC 105 Crude protein determination in cereals and cereal products for food and feed.
• ISO 2171 Cereals and milled cereal products - total ash determination
• AOAC 14022, ISO 7305 Fat acidity determination in milled cereal products.
• AOAC 7070, ICC 113 The value of crude fiber is calculated.
• ISO 5223. Cereal test sieves with 4.5mm sieve
  
  

Eurofins' analytical offer for authenticity testing

Authenticity analyses are "made-to-measure" for each product and include basic methods and specific tests, selected to check for likely adulteration practices.

Eurofins' specific expertise is in the use of isotopic techniques and in particular a method of reference in authentication: SNIF-NMR® (Site-Specific Natural Isotope Fractionation Studied by Nuclear Magnetic Resonance). This is one of the most powerful techniques for detecting the adulteration of natural products.

In addition, Eurofins uses a variety of traditional physical, chemical, and biological procedures, such as liquid or gas chromatography, spectroscopy (atomic absorption, ultraviolet), and a wide array of analytical tools to check the validity of the products.

Due to the fact that fraud is frequently created to circumvent the tests in use, it is getting harder and harder to identify using simple analyses. To find non-compliant items, therefore, sophisticated analytical methods must be used. With a significant investment in research and development, Eurofins can use the best techniques for each unique situation for determining the authenticity of a product.

Additionally, Eurofins provides the option of establishing a focused analytical strategy and particular data banks to assist in defending producers against imitative goods or false claims of geographic origin, particularly in the case of PDO (Protected Denomination of Origin) certification.

References

1. https://iimr.icar.gov.in/maize-biology/
2. http://maize.teacherfriendlyguide.org/index.php
3. http://agropedia.iitk.ac.in/content/classification-maize-types
4. https://www.taylorfrancis.com/chapters/edit/10.1201/97804290529417/authenticity-maize-corn-
5. https://www.vicam.com/markets/corn-maize
6. CODEX STANDARD FOR MAIZE (CORN) CODEX STAN 153-1985
7. https://foodsafetyhelpline.com/fssai-drafts-standards-pulses-honey-food-grains/
8. https://www.sciencedirect.com/science/article/pii/S0924224421004167

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