Pea (Pisum sativum L. ssp. sativum) is an annual herbaceous plant from the legume family (Fabaceae). It has high nutritional value and, as a vegetable crop, is classified among grain legumes.
Peas have several centers of origin, with the most significant being Central Asia (northwestern India, Pakistan, and Afghanistan), followed by the centers in Asia Minor, Iran, the Mediterranean, and the mountainous areas of Ethiopia. Humans did not use wild peas for food, even though the oldest pea finds date back to the Neolithic period. Peas were found in ancient Greek tombs dating back 6,000 years before Christ, and in southern Russia in 5,000-year-old archaeological layers. Peas arrived in Europe at the beginning of the Middle Ages during the great migrations. Europeans in the 17th century enjoyed preparing their favorite dishes from peas.
Peas are an annual herbaceous plant. They contain proteins (legumin, legumelin, vicilin, trigonelline, etc.), sugar, starch, lecithin, and more. A higher amount of lecithin is found in varieties with wrinkled seeds, where chlorophyll is preserved longer, resulting in mature seeds of these varieties being distinctly green.
Nutritional Value of Peas
Pea seeds at technological maturity are used as food, prepared in various ways. Peas are preserved by sterilization and freezing.
As already mentioned, peas are a nutrient-rich food with a balanced ratio of proteins and carbohydrates. About 90% of the proteins are globulins, and at technological maturity, sugars and starch are in a 1:1 ratio. The nutritional value and mineral-vitamin composition of young and mature pea seeds are listed in the following tables.
| Nutrient | % in Young Seeds | % in Mature Seeds |
|---|---|---|
| Crude Proteins | 3.5 – 7.2 | 20 – 24.5 |
| Crude Fats | 0.37 – 0.53 | 1.1 – 2.1 |
| Carbohydrates | 12 – 16 | 52.5 – 61.7 |
| of which Sugar | up to 6.8 | |
| Fiber | 1.5 – 2.2 | 1.2 – 5.6 |
| Minerals | 0.85 – 1.1 | 2.4 – 2.8 |
| Water | 74 – 78 | 9 – 14 |
Table 1: Nutritional Value of Peas
| Mineral | mg/100 g in Young Seeds | mg/100 g in Mature Seeds |
|---|---|---|
| Sodium | 0.5 – 4 | up to 4 |
| Potassium | 228 – 370 | up to 810 |
| Magnesium | 22 – 43 | |
| Calcium | 20 – 34 | 74 – 146 |
| Phosphorus | 80 – 145 | 268 – 400 |
| Sulfur | up to 34 | |
| Iron | 1.7 – 3.4 | 4.7 – 6 |
Table 2: Mineral Composition of Peas
| Vitamin | mg/100 g in Young Seeds | mg/100 g in Mature Seeds |
|---|---|---|
| Carotene | 0.2 – 0.68 | 0.15 – 0.22 |
| E | 4 – 6 | 5 – 6 |
| K | 0.28 | 0.71 |
| B1 | 0.15 – 0.5 | 0.21 – 1.1 |
| B2 | 0.11 – 0.3 | 0.15 – 3 |
| B3 | 1.8 – 2.9 | 1.8 – 3.2 |
| B5 | 0.4 – 1 | |
| B6 | 0.093 – 0.19 | |
| C | 15 – 137 |
Table 3: Vitamin Content
Morphological Properties of Peas
The pea fruit is a pod. Depending on the cultivar, its length varies from 4 – 12 cm, and it can be flattened or cylindrical with a blunt or pointed tip. The pod contains 4 – 12 ovules, which, under favorable fertilization conditions, develop into seeds. The seed is round to slightly cylindrical at technological maturity and comes in various shades of green. Peas are a plant of temperate climates, and mild temperatures are most favorable for the growth and development of this crop. The optimal temperature for germination and emergence is 20°C, while the minimum is 5°C.
The main root of the pea sometimes reaches a depth of 1 m, but most lateral roots are found in the top 30 cm of the soil. Pea roots, like those of other legumes, have nodules that form a symbiosis with bacteria from the genus Rhizobium. These bacteria fix elemental nitrogen from the air, which is unavailable to the plant in its elemental form, converting it through biochemical processes into ammonium (NH4+), which is readily available to plants. Pink nodules indicate active bacteria and ongoing nitrogen fixation.
The stem is angular, hollow, light green, and more or less branched (depending on the plant’s density). It ranges in height from 30 – 200 cm. Tall cultivars require support to keep the stem upright.
The leaves are pinnate with one, two, or rarely three pairs of oval leaflets and end with a branched tendril. The leaf surface is covered with a waxy coating.
The pea flower is butterfly-shaped with five petals (2 forming a keel, 2 wings, and 1 standard) and is white in color. Peas predominantly self-pollinate.
Pea seeds can be round and smooth or irregularly round and wrinkled, with a yellow or green color.
