How Much Protein Is in an Ear of Corn: Key Facts
An average medium ear of sweet corn (about 100 grams of kernels) provides roughly 3 to 4 grams of protein. This amount can vary with corn variety, ripeness at harvest, and how the kernels are measured (with or without cob). While corn is primarily a source of carbohydrate, it also contributes small but meaningful amounts of protein, especially in diets where corn is a staple. The following sections explain how protein content is measured, what influences it, and how it compares with other common foods.
Standard Serving Sizes and Typical Protein Values
Because portion sizes differ in real-world settings, it helps to see protein numbers for common units. A single medium raw ear of sweet corn (≈100 g edible kernels) supplies about 3–4 g protein. By contrast, a cup of sweet corn kernels (≈150 g) yields roughly 5–6 g. When estimating per 100 g of kernels, most sweet corn varieties deliver close to 3.5 g. As a point of reference, field (dent) corn used for livestock and processed foods shows similar protein per weight, though fewer people eat it directly as whole ears.
Quick Reference Table: Common Portions and Protein
| Portion | Approximate Weight (g) | Protein (g) | Notes |
|---|---|---|---|
| 1 medium ear, raw (kernels only) | ≈100 | 3–4 | Sweet or dent corn; values vary by variety and measurement method |
| 1 cup kernel pieces | ≈150 | 5–6 | Cooked or raw kernels; slight changes with moisture |
| 100 g kernels | 100 | ≈3.5 | USDA FoodData Central reference for raw sweet corn kernels |
| 1 large ear (heavier) | ≈150–180 | 5–6 | If measured with some cob; estimates for kernels only are slightly lower per gram |
Factors That Influence Protein Content
The protein in an ear of corn depends on genetic variety, growing conditions, and how the corn is harvested and prepared. Sweet corn bred for fresh eating tends to have slightly lower protein than some dent corns used industrially, but both are primarily carbohydrate sources. Ripeness at harvest matters: kernels picked earlier may have less protein than fully matured kernels, though the difference is modest. Cooking or boiling causes minor losses due to leaching into water, but most protein remains in the kernels. Weighing kernels separately from the cob ensures more consistent comparisons across sources.
Corn Variety and Maturity Effects
- Sweet corn: Typically 3–4 g protein per 100 g; bred for flavor and texture.
- Dent or field corn: Similar protein by weight, but different usage patterns (animal feed, milling).
- Early harvest vs. mature kernels: Mature kernels usually contain slightly more protein per unit weight.
- Processing: Wet milling and drying can concentrate or slightly alter protein measurements, but whole-kernel values remain in the 3–4 g per 100 g range.
How Corn Protein Compares to Other Foods
On a per-100-gram basis, the protein in corn is modest compared with many other staples. Cooked chicken breast, for example, provides about 30 g protein per 100 g, while canned tuna can exceed 25 g. Legumes such as cooked lentils offer roughly 9 g per 100 g, and soy products like tofu provide 8–10 g. Grains like cooked rice contribute only 2–3 g per 100 g, placing corn in a similar range but with slightly higher protein than many refined grains. As a component of a varied diet, corn adds meaningful protein alongside fiber and energy-providing carbohydrates.
Quick Comparison
- Corn kernels (100 g): about 3–4 g protein
- Cooked rice (100 g): about 2–3 g protein
- Lentils, cooked (100 g): about 9 g protein
- Chicken breast, cooked (100 g): about 30 g protein
Practical Tips for Measuring Corn Protein
To estimate protein from an ear of corn with reasonable accuracy, remove kernels when possible and weigh them. A standard medium sweet corn ear typically weighs about 100–130 g total, with roughly 70–80 g as edible kernels. Measuring kernel weight and applying the 3–4 g protein per 100 g rule gives a reliable estimate. If weighing is not practical, assume one medium ear without the cob contributes approximately 3–4 g protein. For meal planning, treat corn as a carbohydrate-rich side that also provides small protein contributions rather than a primary protein source.
Key Takeaways
A typical ear of sweet corn offers around 3–4 grams of protein per 100 grams of kernels, with medium ears yielding roughly 3–4 g total. Growing conditions, variety, and ripeness cause modest variation, while cooking causes minor losses. Corn’s protein complements its carbohydrate role and can meaningfully contribute to overall intake when eaten regularly as part of a balanced diet. For practical purposes, counting one medium ear as about 3–4 g of protein is a reasonable, evidence-based estimate.