Soy sauce 
Soy (Glycine max L.; family Fabaceae)
Description
Annual legume valued for protein- and oil-rich seeds; used as whole foods (edamame, tofu, tempeh, miso), as functional ingredients (flours, TVP/textured vegetable proteins, lecithin), and as an oleochemical feedstock (soybean oil).
Sensory profile ranges from beany/leguminous to neutral (refined or fermented forms).
Caloric value (per 100 g)
Dry seeds: ~430–470 kcal; protein ~34–40 g, fat ~18–21 g, carbohydrate ~25–30 g (of which fiber ~9–15 g).
Cooked seeds: ~150–190 kcal (higher water).
Soybean oil: ~884 kcal.
Key constituents
Proteins: storage globulins 7S β-conglycinin and 11S glycinin (complete amino-acid profile; limiting methionine).
Lipids (seed oil ~18–21%): PUFA (polyunsaturated fatty acids) n-6 (linoleic), PUFA n-3 (ALA/alpha-linolenic acid), MUFA (monounsaturated fatty acids) oleic, SFA (saturated fatty acids) palmitic/stearic.
Carbohydrates: low starch; raffinose/stachyose oligosaccharides; soluble/insoluble fiber.
Phytochemicals: isoflavones (genistein, daidzein, glycitein), phytosterols, saponins, phytic acid.
Micronutrients: K, Mg, Fe, folate, vitamin K, choline/lecithins.
Antinutrients (raw): trypsin inhibitors (Kunitz/Bowman–Birk), lectins—inactivated by toasting/cooking or fermentation.
Production process
Primary processing: harvest → cleaning/dehulling.
Oil: pressing ± solvent extraction → refining (degum, neutralize, bleach, deodorize).
Flours/TVP: defatting, toasting (antinutrient inactivation), extrusion/texturization.
Fermented products: inoculation and aging (tempeh, miso, shoyu).
Tofu/soy drinks: hot grinding → filtration → coagulation (nigari/CaSO₄) → pressing.
Controls: moisture, urease activity/PDI, TIU (trypsin inhibitors), isoflavone HPLC, GMO identity-preserved traceability.
Sensory and technological properties
Lecithin + proteins: emulsification, foaming, water/oil binding, film forming.
Fermentation: reduces beany notes and FODMAP oligosaccharides; elevates umami.
Oil: good flavor carry, tenderizing in bakery; refined oil supports stable frying.
Food uses
Ingredients: flours/grits, protein concentrates/isolates, TVP, lecithin (E322), soybean oil.
Products: edamame, soy drinks/yogurt, tofu/tempeh, miso, natto, soy sauce, plant-based meats.
Typical inclusions: lecithin 0.1–1% (emulsifier), isolates 1–10% (bakery, meats, beverages); oil as required.
Nutrition and health
Provides high-quality protein and fiber; fat profile favorable for MUFA/PUFA (see lipid profile).
Isoflavones are phytoestrogens with dose- and context-dependent effects; avoid unauthorized health claims.
Oligosaccharides can contribute to FODMAP load; long cooking or fermentation reduces them.
Major EU allergen: avoid in soy-allergic individuals.
With thyroid disorders or hormonal therapies, discuss high intake of soy/isoflavones with a clinician.
Lipid profile (soybean oil, % of total fatty acids)
SFA (saturated fatty acids) ~14–16% (palmitic, stearic).
MUFA (monounsaturated fatty acids) ~20–30% (mostly oleic).
PUFA (polyunsaturated fatty acids) ~50–62%: linoleic n-6 ~45–55%, ALA n-3 ~5–9%.
TFA (trans fatty acids): avoid partially hydrogenated oils; natural trans negligible.
Health note: higher MUFA/PUFA vs SFA generally supports a better blood-lipid profile; balance overall n-6/n-3 intake. MCT (medium-chain triglycerides) are not characteristic of soy.
Quality and specifications (typical topics)
Seeds/flours: moisture, protein (N×6.25), ash, PDI/KOH solubility, TIU, urease activity, mycotoxins (e.g., aflatoxins), pesticides/metals.
Oil: FFA/acid value, peroxides/p-anisidine, phospholipids (degumming), color, oxidative stability (e.g., Rancimat).
Lecithin: acetone-insolubles, viscosity, color, acid value.
GMO: segregation/testing per regulatory labeling.
Storage and shelf-life
Seeds/flours: cool, dry, protected from light/oxygen; risk of rancidity; typical shelf-life 12–18 months in barrier packs (FIFO).
Oil: cool, dark, tight closure; consider antioxidants; shelf-life 6–18 months depending on refining.
Lecithin: hygroscopic—avoid high RH.
Allergens and safety
Soy is a major EU allergen (applies to flours, protein products, crude oil; some regions exempt highly refined oil).
Prevent cross-contact; manage allergen CCP under HACCP.
Ensure adequate toasting/process to reduce antinutrients (specs for TIU/urease).
INCI functions in cosmetics
Glycine Soja (Soybean) Oil (emollient, skin conditioning), Lecithin/Hydrogenated Lecithin (emulsifiers, delivery), Hydrolyzed Soy Protein/Soy Amino Acids (conditioning), Glycine Soja Sterols (stabilizers/lipid replenishment), Phosphatidylcholine (solubilizer).
Troubleshooting
Beany flavor: rapid heat inactivation of lipoxygenase; low-LOX cultivars; use fermentation.
Excess foam in beverages: optimize lecithin/protein ratio and homogenization.
Rancidity in seeds/flours/oil: improve O₂/light barriers, reduce metals/heat; use permitted chelators/antioxidants.
Weak TVP texture: adjust moisture/extrusion profile and particle size; add compatible protein binders.
Sustainability and supply chain
Nitrogen-fixing crop (reduces synthetic N) but watch deforestation/land use; prefer certified, traceable supply.
Manage processing effluents to BOD/COD targets; recyclable packaging; audits under GMP/HACCP.
Conclusion
Soy is a versatile, technical ingredient delivering proteins, lecithins, and oil with a favorable lipid profile. Proper processing (antinutrient inactivation), stringent allergen control, oxidative stability, and robust traceability ensure quality and safety across diverse food and cosmetic applications.
Mini-glossary
SFA — Saturated fatty acids: limit excess; higher intakes can raise LDL cholesterol.
MUFA — Monounsaturated fatty acids (e.g., oleic): generally favorable/neutral for blood lipids.
PUFA — Polyunsaturated fatty acids (n-6/n-3): beneficial when balanced; soy oil is rich in linoleic n-6 with ALA n-3.
ALA — Alpha-linolenic acid (n-3): plant n-3; precursor to EPA/DHA, with limited human conversion.
EPA/DHA — Long-chain n-3 fatty acids with cardiometabolic benefits; mainly from fish (not soy).
TFA — Trans fatty acids: avoid industrial TFA from partially hydrogenated oils; natural trans are negligible in soy.
MCT — Medium-chain triglycerides: not characteristic of soy.
PDI/KOH — Protein dispersibility index / KOH solubility: indicators of protein functionality in flours/isolates.
TIU — Trypsin inhibitor units: measure of antinutritional activity; must be low after adequate heat treatment.
LOX — Lipoxygenase: enzyme causing beany notes; inactivate by heat.
GMP/HACCP — Good Manufacturing Practice / Hazard Analysis and Critical Control Points: hygiene and preventive-safety frameworks with defined CCP.
BOD/COD — Biochemical/Chemical Oxygen Demand: effluent-impact indicators used in wastewater management.
FIFO — First in, first out: inventory rotation that uses older lots first.
References__________________________________________
Orts A, Revilla E, Rodriguez-Morgado B, Castaño A, Tejada M, Parrado J, García-Quintanilla A. Protease technology for obtaining a soy pulp extract enriched in bioactive compounds: isoflavones and peptides Heliyon. 2019 Jun 22;5(6):e01958. doi: 10.1016/j.heliyon.2019.e01958.
Abstract. This work presents a new bioprocess process for the extraction of bioactive components from soy pulp by-product (okara) using an enzymatic technology that was compared to a conventional water extraction. Okara is rich in fiber, fat, protein, and bioactive compounds such as isoflavones but its low solubility hampers the use in food and fertilizer industry. After the enzymatic attack with endoproteases half of the original insoluble proteins were converted into soluble peptides. Linked to this process occured the solubilization of isoflavones trapped in the insoluble protein matrix. We were able to extract up to 62.5% of the total isoflavones content, specially aglycones, the more bioactive isoflavone forms, whose values rose 9.12 times. This was probably due to the increased solubilization and interconversion from the original isoflavones. In conclusion, our process resulted in the formulation of a new functional product rich in aglycones and bioactive peptides with higher antioxidant potency than the original source. Therefore, we propose that the enzymatic extraction of okara bioactive compounds is an advantageous tool to replace conventional extraction.
González Cañete N, Durán Agüero S. Soya isoflavones and evidences on cardiovascular protection. Nutr Hosp. 2014 Jun 1;29(6):1271-82. doi: 10.3305/nh.2014.29.6.7047. Spanish.
Roccisano D, Henneberg M, Saniotis A. A possible cause of Alzheimer's dementia - industrial soy foods. Med Hypotheses. 2014 Mar;82(3):250-4. doi: 10.1016/j.mehy.2013.11.033. Epub 2013 Dec 7.
Seeley AD, Jacobs KA, Signorile JF. Acute Soy Supplementation Improves 20-km Time Trial Performance, Power, and Speed. Med Sci Sports Exerc. 2020 Jan;52(1):170-177. doi: 10.1249/MSS.0000000000002102.
Abstract. Introduction: Isoflavones, a chemical class of phytoestrogens found in soybeans and soy products, may have biological functions similar to estradiol. After binding with ERβ or perhaps independently of estrogen receptors, isoflavones may augment vascular endothelial relaxation, contributing to improved limb blood flow. Purpose: To determine if acute fermented soy extract supplementation influences 20-km time trial cycling performance and cardiac hemodynamics compared with a placebo. Methods: Subjects included 25 cyclists and triathletes (31 ± 8 yr, V˙O2peak: 55.1 ± 8.4 mL·kg·min). Each subject completed a V˙O2peak assessment, familiarization, and two 20-km time trials in randomized order after ingestion of a fermented soy extract supplement or placebo. The fermented soy extract consisted of 30 g powdered supplement in 16 fl. ounces of water. The placebo contained the same quantities of organic cocoa powder and water. Each trial consisted of 60 min of rest, 30 min at 55% Wpeak, and a self-paced 20-km time trial. Results: Soy supplementation elicited a faster time to 20-km completion (-0.22 ± 0.51 min; -13 s), lower average HR (-5 ± 7 bpm), and significantly greater power (7 ± 3 W) and speed (0.42 ± 0.16 km·h) during the last 5 km of the time trial compared with placebo. Analysis of the results by relative fitness level (<57 vs ≥ 57 mL⋅kg⋅min) indicated that those with a higher level of fitness reaped the largest performance improvement alongside a reduced HR (-5 ± 7 bpm). Conclusions: Ingestion of a fermented soy extract supplement improved sprint-distance performance through improvements in both power and speed. For those with great aerobic fitness, soy supplementation may help to decrease cardiac demand alongside performance improvement.
Sedaghat A, Shahbazian H, Rezazadeh A, Haidari F, Jahanshahi A, Mahmoud Latifi S, Shirbeigi E. The effect of soy nut on serum total antioxidant, endothelial function and cardiovascular risk factors in patients with type 2 diabetes. Diabetes Metab Syndr. 2019 Mar - Apr;13(2):1387-1391. doi: 10.1016/j.dsx.2019.01.057
Nachvak SM, Moradi S, Anjom-Shoae J, Rahmani J, Nasiri M, Maleki V, Sadeghi O. Soy, Soy Isoflavones, and Protein Intake in Relation to Mortality from All Causes, Cancers, and Cardiovascular Diseases: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies J Acad Nutr Diet. 2019 Jul 2. pii: S2212-2672(19)30362-4. doi: 10.1016/j.jand.2019.04.011
Woo HW, Kim MK, Lee YH, Shin DH, Shin MH, Choi BY. Habitual consumption of soy protein and isoflavones and risk of metabolic syndrome in adults ≥ 40 years old: a prospective analysis of the Korean Multi-Rural Communities Cohort Study (MRCohort). Eur J Nutr. 2019 Oct;58(7):2835-2850. doi: 10.1007/s00394-018-1833-8.
Abstract. Purpose: Although considerable attention has been paid to the potential benefits of soy protein and isoflavones for preventing metabolic syndrome (MetS) and its components, findings linking habitual consumption of these factors to MetS are limited. This study aimed to evaluate the association of MetS incidence with habitual intake of soy protein/isoflavones among Korean men and women aged ≥ 40 years old who did not have MetS at baseline (n = 5509; 2204 men and 3305 women). Methods: Dietary intake of soy protein/isoflavones at baseline and average consumption during follow-up were used. Results: A significant inverse association between dietary intake and incidence of MetS was found in women (incidence rate ratios, IRR = 0.60, 95% CI = 0.46-0.78, P for trend = 0.0094 for the highest quintile of average soy protein intake compared with the lowest quintile; IRR = 0.57, 95% CI = 0.44-0.74, P for trend = 0.0048 for the highest quintile of average isoflavones intake compared with the lowest quintile). A tendency towards an inverse association was also found in men, although it was not significant for the highest quintile (IRR = 0.80, 95% CI = 0.58-1.11, P for trend = 0.9759, comparing the lowest to the highest quintile of average soy protein intake; IRR = 0.73, 95% CI = 0.53-1.01, P for trend = 0.8956, comparing the lowest to the highest quintile of average isoflavones intake). In terms of individual abnormalities, a significant inverse association was found between soy protein and isoflavones and the incidence of low-high-density lipoprotein cholesterol in both men and women. Abdominal obesity and elevated blood pressure were inversely related to soy protein/isoflavones only in women, and an inverse association of elevated triglyceride appeared only in men. Conclusion: Our findings suggest that habitual intake of soy protein and isoflavones is inversely associated with the risk of MetS and its components. There is likely to be a reverse J-shaped association of average intake with MetS.
