Corn kernels

Corn kernels, often simply called “corn”, are small yellow (or other colored) seeds that come from the corn plant. This plant grows on large fields and loves warmth and sun. Corn is one of the world’s most important cereals and is grown in many countries, for example the USA, Brazil, China, Argentina, South Africa, France, Hungary, Ukraine and also in Germany. Because corn is so popular and grown in many places, corn kernels are available in supermarkets almost year-round. Depending on the form – fresh, frozen, canned or dried – you will find corn kernels in different departments.

How does corn get to us?
The corn plant produces cobs that are equipped with many rows of kernels. When corn is harvested young, it is juicy and sweet – this is called “sweet corn.” These sweet kernels are enjoyed as a vegetable. If the corn matures longer and dries, the kernels become harder. This produces varieties better suited for milling (for flour, polenta or corn grits) or for popping (popcorn). Producers harvest, sort and process the kernels so they arrive in stores as fresh cobs, loose kernels, canned goods or frozen products.

Season and availability
Fresh corn cobs are usually in season here in late summer. Then they taste especially sweet. Outside the season you can still get corn easily as canned or frozen. Frozen and canned corn kernels are practical because they have a long shelf life and can be prepared quickly. Dried kernels (for example for popcorn) keep very well in well‑sealed bags.

Corn kernels are the botanical seeds of the cultivated species Zea mays L., belonging to the grass family (Poaceae). As endosperm‑based caryopses they combine structural, chemical and functional properties that make them versatile in both nutrition and industrial applications. The structure of a corn kernel includes pericarp (seed coat), endosperm, embryo (germ) and the aleurone layer. The pericarp is composed mainly of cellulose, hemicellulose and lignin and protects the inner matrix from physical and microbial influences. The endosperm is rich in starch and protein; it is divided into floury and vitreous zones characterized by different density and protein‑starch interactions. The embryo contains lipids, vitamins and enzymes that are essential for germination.

The chemical composition of corn kernels varies depending on variety, location, harvest year and post‑harvest maturation. Typical ranges (on a dry matter basis) are: Starch 60–75 %, Protein 7–12 %, Fat 3–5 %, Crude fiber 1–3 %, Ash 1–2 %. The protein profile is dominated by prolamins (zeins), which are low in lysine and tryptophan; quality protein maize varieties (QPM) have been bred to improve the essential amino acid balance. The lipid fraction is rich in unsaturated fatty acids, particularly linoleic acid (C18:2) and oleic acid (C18:1), with minor amounts of palmitic acid. Important micronutrients include B vitamins (B1, B3, B6, folate), vitamin E (tocopherols, especially in the germ), and minerals such as magnesium, phosphorus, potassium, zinc and iron. Carotenoids (lutein, zeaxanthin) are pronounced in yellow kernels and contribute to antioxidant capacity.