Pulses & Legumes
Soya Beans
1.1 Overview & Structure
The soya bean is widely regarded as the ultimate “protein engine” because it provides a complete plant protein, meaning it contains all nine building blocks the body cannot make itself¹, ¹⁸. Physically, the bean is constructed with a dense matrix of polyunsaturated fats and proteins protected by a sturdy outer hull made of cellulose and hemicellulose¹, ⁴. These tough cell walls are the reason the bean feels firm; they act as a structural cage that slows down the digestive process, allowing the body to absorb energy steadily over time¹, ¹⁴.
1.2 Physical & Culinary Performance
In its raw state, the soya bean is extremely hard and contains trypsin inhibitors, which are natural compounds that interfere with how we digest protein⁹. Cooking is essential because heat deactivates these inhibitors and softens the bean’s thickness, making the nutrients accessible⁹. When processed into tofu, the bean proteins form a soft curd, while fermentation into tempeh uses a friendly mould to break down the bean’s structure, making it even easier to digest¹⁸. Young green beans, known as edamame, are softer and are often steamed, whereas the mature beans are better suited for long boiling or pressure cooking¹², ¹⁸.
1.3 Storage & Life Hacks
Dried soya beans are very shelf-stable if kept in a cool, dry place away from light, which can cause the natural fats to spoil or go rancid¹. A powerful “life hack” for nutrition is sprouting the beans for four to six days, which significantly raises the levels of Vitamin C and makes the minerals easier to absorb¹². In the kitchen, using the beans to make home-made soya milk provides a fresh base for various recipes, while the leftover pulp, or okara, is a clever high-fibre addition to baked goods¹, ¹⁴.
1.4 Suitability & Ethics
Soya is one of the “top 14” major allergens, so it must be clearly labelled on food packaging¹⁶. While it is naturally gluten-free, some sauces made from soya, such as shoyu, often contain wheat⁷. Ethically, soya is a highly efficient crop because it fixes nitrogen into the soil, but global demand can drive land-use changes in sensitive areas¹⁰, ¹². Some sources describe choosing organic or locally grown soya as a way to ensure more sustainable farming practices¹.
1.5 Seasonality & Environment
Soya beans require warm soil and a long growing season of up to 120 days, typically reaching harvest in the UK during the late summer¹². Environmentally, soya is a champion; producing one kilogram of soya protein creates roughly 70 times less carbon dioxide than producing the same amount of beef¹¹. It also has a very efficient water footprint, using less water than many other pulse varieties¹⁵.
1.6 Safety & Consumption Context
Some sources describe soya as a food that should be eaten as part of a balanced diet, with traditional soy-heavy cultures typically consuming it in fermented forms like tempeh or miso¹, ¹⁸. It contains trace amounts of goitrogens, which are substances that might affect how the body takes up iodine, though this is usually only a concern for people who are already very low in iodine¹⁸. For most people, a few portions a day are considered a healthy way to meet protein needs¹⁸.
1.7 Health & Nutrition Superpower
The soya bean’s “superpower” is its immense concentration of Molybdenum, a mineral that helps the body process certain amino acids, alongside high levels of Folate and Copper³, ⁴. It is also rich in isoflavones, which are plant-based compounds that can help support bone density and keep cholesterol levels healthy¹⁸. Additionally, it provides a rare plant source of omega-3 fats, which are essential for heart and brain health¹, ⁴.
1.8 Microbial & Amino Profile
Fermenting soya beans to make tempeh completely changes their nutritional profile by using the Rhizopus mould to pre-digest the proteins¹⁸. This process deactivates phytic acid, which is a “mineral blocker” that otherwise stops the body from taking in zinc and iron⁹. The result is a food with superior digestibility and a rich array of amino acids, particularly tryptophan and serine, which support mood regulation and cellular repair⁴, ⁵.
1.9 Enzymatic Activity & Freshness
When soya is harvested early as edamame, it retains higher levels of natural enzymes and Vitamin C compared to the dried, mature seeds¹². These young beans are “living” structures where the sugars have not yet fully converted into complex starches, giving them a sweeter taste and a different enzymatic profile¹. Once the bean matures and dries, these enzymes become dormant until they are reactivated by soaking or sprouting in the kitchen¹, ¹².
Land-Use & Human Labour Efficiency & Scoring
Nutrients per Hectare (N/H) Scoring
- Traditional Production Score: 62/100. Soya is already one of the world’s most productive crops per hectare, providing massive amounts of protein compared to livestock. However, traditional monoculture farming consumes vast horizontal space and relies on single-season cycles¹⁰.
- Ultra-Efficient Production Score: 95/100. As the most efficient method of production isn’t traditional outdoor methods or indoor aeroponics, soya thrives in the proposed 8-storey model. Hidden underground storeys provide controlled environments for consistent root growth and nitrogen fixation, while the roof farm allows for natural maturation. This system multiplies the Total Nutrient Score (Nutrient Aggregate) by stacking production vertically, making it a cornerstone of global food security¹.
Human Labour Intensity (HLI) Scoring
- Traditional Labour Score: 31/100. While harvesting is mechanised, the “Labour Burden” is high due to the complex global supply chain, including the intensive processing required to turn raw beans into tofu, oils, and textured proteins¹.
- Automated Labour Score: 10/100. In the 8-storey model, soya is a ‘Labour Liberator’. Automation handles the monitoring of nutrient-rich aeroponic mists and the heavy lifting of the harvest. AI systems manage the “Zero Air-Loss” environment, reducing human intervention to high-level technical oversight and bringing the score towards ‘Labour Liberation’¹.
This audit provides a comprehensive nutritional and environmental profile for Raw Soya beans (Glycine max), including their young, green form, Edamame. Within the Pulse & Legume Power group, soybeans are the ultimate “protein engine”, providing a “complete” plant protein with all nine essential amino acids. They are the group’s champion for Molybdenum, Folate, and Iron, while offering a dense matrix of polyunsaturated fats and unique isoflavones. In a vegan diet, soybeans are the most versatile substrate, forming the basis for tofu, tempeh, and textured protein, supporting both muscle synthesis and metabolic health.
Data Tables
1. Main Nutrients Table
Strictly sorted in descending order by % Ref Value per 20g Protein Portion (54.95 g). All details provided are for Soybeans (Raw, Mature seeds).
| Nutrient | % Ref Value per 20g Protein Portion (54.95 g) | % Ref Value per 200 Cals | % Ref Value per 100g | Amount per 100g |
| Molybdenum | 185.0%² | 76.2%² | 336.7%² | 252.5 mcg³ |
| Copper | 76.0%² | 31.3%² | 138.3%² | 1.66 mg⁴ |
| Manganese | 74.4%² | 30.6%² | 135.5%² | 2.52 mg⁴ |
| Phosphorus | 55.2%² | 22.7%² | 100.4%² | 703.0 mg⁴ |
| Folate (B9) | 51.5%² | 21.2%² | 93.8%² | 375.0 mcg⁴ |
| Magnesium | 49.6%² | 20.5%² | 90.3%² | 280.0 mg⁴ |
| Protein | 44.4%² | 18.3%² | 80.9%² | 36.4 g⁴ |
| Vitamin B1 | 43.5%² | 17.9%² | 79.1%² | 0.87 mg⁴ |
| Vitamin B2 | 43.4%² | 17.9%² | 79.1%² | 0.87 mg⁴ |
| Iron | 29.3%² | 12.1%² | 53.4%² | 15.7 mg⁴ |
| Potassium | 28.2%² | 11.6%² | 51.3%² | 1797.0 mg⁴ |
| Zinc | 27.5%² | 11.3%² | 50.0%² | 4.9 mg⁴ |
| Vitamin B6 | 18.8%² | 7.8%² | 34.3%² | 0.38 mg⁴ |
| Fibre | 16.5%² | 6.8%² | 30.0%² | 9.0 g⁴ |
| Selenium | 16.3%² | 6.7%² | 29.7%² | 17.8 mcg⁴ |
| Total Fat | 14.0%² | 5.8%² | 25.5%² | 19.9 g⁴ |
| Energy (kcal) | 12.3%² | 10.0%² | 22.3%² | 446 kcal⁴ |
| Saturated Fat | 6.6%² | 2.7%² | 12.0%² | 2.88 g⁴ |
| Vitamin B3 | 6.5%² | 2.7%² | 11.9%² | 1.66 mg⁴ |
| Carbohydrate | 6.2%² | 2.6%² | 11.3%² | 30.2 g⁴ |
| Vitamin C | 3.3%² | 1.4%² | 6.0%² | 6.0 mg⁴ |
| Vitamin E | 3.1%² | 1.3%² | 5.7%² | 0.85 mg⁴ |
| Sodium | 0.1%² | 0.0%² | 0.1%² | 2.0 mg⁴ |
| Vitamin B12 | 0.0%² | 0.0%² | 0.0%² | 0.0 mcg⁴ |
2. Amino Acid Table
Strictly sorted in descending order by % Ref Value per 20g Protein Portion (54.95 g). All details provided are for Soybeans (Raw).
| Amino Acid | % Ref Value per 20g Protein Portion (54.95 g) | Amount per 100g |
| Serine | 129.1%² | 2.35 g⁴ |
| Tryptophan | 124.7%² | 0.59 g⁴ |
| Aspartic Acid | 117.4%² | 5.11 g⁴ |
| Arginine | 97.8%² | 3.15 g⁴ |
| Glutamic Acid | 97.4%² | 7.85 g⁴ |
| Histidine | 90.7%² | 1.09 g⁴ |
| Threonine | 87.7%² | 1.58 g⁴ |
| Proline | 84.7%² | 1.91 g⁴ |
| Isoleucine | 82.0%² | 1.97 g⁴ |
| Lysine | 75.3%² | 2.70 g⁴ |
| Alanine | 73.9%² | 1.91 g⁴ |
| Phenylalanine | 70.6%² | 2.12 g⁴ |
| Leucine | 70.5%² | 3.30 g⁴ |
| Valine | 65.2%² | 2.03 g⁴ |
| Tyrosine | 47.9%² | 1.44 g⁴ |
| Glycine | 38.8%² | 1.88 g⁴ |
| Cystine | 36.1%² | 0.65 g⁴ |
| Methionine | 30.0%² | 0.54 g⁴ |
3. Fatty Acid Table
Strictly sorted in descending order by % Ref Value per 20g Protein Portion (54.95 g). All details provided are for Soybeans (Raw).
| Fatty Acid | % Ref Value per 20g Protein Portion (54.95 g) | % Ref Value per 200 Cals | Amount per 100g |
| Polys (Total) | 25.8%² | 10.6%² | 11.26 g⁴ |
| Monos (Total) | 8.3%² | 3.4%² | 4.40 g⁴ |
| Saturated Fat | 6.6%² | 2.7%² | 2.88 g⁴ |
| Omega-3 (ALA) | 6.1%² | 2.5%² | 1.33 g⁴ |
4. Fibre Fractions Table
| Fibre Type | Description | Notes |
| Insoluble Fibre | Cellulose and Hemicellulose | ~80% of total fibre; promotes digestive regularity¹⁴. |
| Soluble Fibre | Galactans and Pectins | Stabilises lipids; fuel for beneficial bifidobacteria¹⁴. |
| Resistant Starch | Prebiotic Starch | Found in cooked/cooled soy; supports gut barrier health¹³. |
5. Anti-Nutritional Factors Table
| Factor | Level | Impact & Mitigation |
| Phytic Acid | High | Binds Zn, Fe, Ca. Mitigation: Fermentation (Tempeh) deactivates⁹. |
| Trypsin Inhibitors | Moderate | Interferes with protein digestion. Mitigation: Thermal cooking⁹. |
| Goitrogens | Trace | May affect iodine uptake in deficient individuals¹⁸. |
6. Phytochemicals Table
| Phytochemical Group | Specific Compounds | Notes |
| Isoflavones | Genistein, Daidzein | Phyto-oestrogens that may lower LDL and support bone density¹⁸. |
| Saponins | Soyasaponin | Anti-inflammatory and potentially anti-carcinogenic bioactive¹⁸. |
| Phytosterols | Beta-sitosterol | Competes with dietary cholesterol for absorption¹⁸. |
7. Allergen & Suitability Table
| Category | Status | Notes |
| Major Allergen | Yes | One of the ‘Top 14’ allergens; mandatory labelling required¹⁶. |
| “Low-FODMAP” (highly-digestible)? | No | High in GOS; Tofu/Tempeh are generally “Low-FODMAP” (highly-digestible)?¹⁷. |
| Gluten-Free | Yes | Naturally free; verify shoyu/soy sauce for wheat content⁷. |
8. Commercial Forms Table
| Form | Description | Notes |
| Edamame | Young soybeans | Higher in Vitamin C; usually steamed in the pod¹². |
| Tofu | Soy milk curd | Versatile; Calcium-set versions are a major mineral source¹⁸. |
| Tempeh | Fermented beans | Superior digestibility due to Rhizopus mould fermentation¹⁸. |
9. Environmental Indicators Table
Strictly sorted in descending order by Value per 20g Protein Portion (54.95 g). All details provided are for Soybeans (Raw).
| Indicator | Value (per 100g) | Value per 20g Protein Portion (54.95 g) | Notes |
| Water Footprint (L) | 415 L¹⁵ | 228.0 L¹⁵ | Efficient; lower than most other pulse varieties¹⁵. |
| Land Use (m²) | 0.8 m²¹⁰ | 0.44 m²¹⁰ | High yield; global demand drives land-use changes¹⁰. |
| Carbon Footprint | 0.08 kg¹⁰ | 0.04 kg¹⁰ | 1kg soy protein is ~70x lower than beef CO2e¹¹. |
10. Home Growing Feasibility Table
| Growing Method | Feasibility | Notes |
| Outdoor Garden | High | Requires warm soil and 80-120 days; nitrogen fixer¹². |
| Sprouting | Very High | Ready in 4-6 days; significantly higher Vitamin C¹². |
Sources & Endnotes – please see the References & Bibliography section for full details of all sources:
- Google AI internal knowledge.
- Google AI – Calculated portion size or percentage based on protein density and reference values.
- NIH – Molybdenum Fact Sheet – nih.gov
- USDA FoodData Central – Soybeans, mature seeds, raw – usda.gov
- FoodStruct – Soybean Amino Acid Profile – foodstruct.com
- MDPI – Nutrient Density of Legumes – mdpi.com
- Coeliac UK – Gluten-free diet and pulses – coeliac.org.uk
- NutritionValue.org – Soybeans raw mature seeds analysis – nutritionvalue.org
- Journal of Food Science – Anti-nutrients in Soy – wiley.com
- Our World in Data – Environmental Impacts of Food – ourworldindata.org
- CarbonCloud – Climate Reports for Soybeans – carboncloud.com
- RHS – Growing Soybeans and Edamame – rhs.org.uk
- The Gut Clinic UK – Resistant Starch – thegutclinicuk.com
- ScienceDirect – Dietary Fiber in Legumes – sciencedirect.com
- Water Footprint Network – Crop Database – waterfootprint.org
- Anaphylaxis UK – Soya Allergy Factsheet – anaphylaxis.org.uk
- Monash University – FODMAP levels in Soy Products – monashfodmap.com
- British Dietetic Association (BDA) – Soya Foods and Health – uk.com
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