Table 1.
Main constituents of soybean, mature seeds, and raw dry soybeans.
| Nutritional value for 100 g | Comments | |
|---|---|---|
| Energy | 1,866 kJ (446 kcal) | |
| Protein | 36.49 g | |
| Essential amino acids: | Soy protein, although plant-derived, is a complete protein; it contains a great quantitative of lysine, while methionine is a limiting amino acid | |
| Histidine | 1.097 g | |
| Isoleucine | 1.971 g | |
| Leucine | 3.309 g | |
| Lysine | 2.706 g | |
| Methionine | 0.547 g | |
| Phenylalanine | 2.122 g | |
| Threonine | 1.766 g | |
| Tryptophan | 0.591 g | |
| Valine | 2.029 g | |
| Other proteins: | ||
| Enzymes | ||
| Lipo-oxygenase | The unpleasant bean flavor typical of soybeans is due to the content of lipo-oxygenase | |
| Urease | Urease is present in uncooked soybean and is progressively destroyed by heat, so it can be used as an indicator of adequate heat treatment | |
| Antinutritional factors: | ||
| Soy protease inhibitors | Soy protease inhibitors reduce protein digestibility | |
| Lectins | Lectins can interfere with micronutrient absorption | |
| Fatsa | 19.94 g | The fat content consists mainly of unsaturated fatty acids, with smaller amounts of saturated fatty acids and no cholesterol |
| Saturated | 2.884 g | |
| Monounsaturated | 4.404 g | Soy is high in polyunsaturated fatty acids, which are essential fatty acids with a hypocholesterolemic effect |
| Polyunsaturatedb | 11.255 g | Omega-3 ALA 0.72–2.16% Omega-6 LA 6.48–11.6% |
| Carbohydrates | 30.16 g | |
| Sugars | 7.33 g | Soluble sugars increase palatability, thus potentially causing flatulence |
| Dietary fiber | 9.3 g | Dietary fiber is a non-digestible portion of food. In soybean, it is composed of lignin, enzyme-resistant starch and oligosaccharides, and cell wall polysaccharides (cellulose, hemicellulose, and pectins) |
| Mineralsc | Although soybean's mineral content is high, bioavailability is slow since phytate reduces the absorption of dietary minerals, particularly for zinc and iron | |
| Potassium | 1.797 mg | |
| Calcium | 277 mg | |
| Magnesium | 280 mg | |
| Copper | 1.658 mg | |
| Iron | 15.7 mg | |
| Zinc | 4.89 mg | |
| Other constituents | ||
| Phytic acid | Phytic acid impairs mineral absorption and may promote mineral deficiencies | |
| Isoflavoned | Plant compounds have lower estrogenic activity than the human female hormone 17-β-estradiol and other estrogenic receptor-independent effects, which can play a role in normal sexual development and reproductive function | |