📊 Full nutrition facts — per 100g
| Nutrient | Amount | % Daily value | Level |
|---|---|---|---|
| Calories | 508 kcal | 25% | |
| Carbohydrates | 28.1g | 9% | |
| Dietary fibre | 12.2g | 44% | |
| Protein | 26.1g | 52% | |
| Total fat | 36.2g | — | |
| GI | ~35 — Low | — | |
| Selenium | 208µg | 378% | |
| Calcium | 266mg | 27% | |
| Magnesium | 370mg | 93% | |
| Iron | 9.21mg | 51% | |
| Glucosinolates | high — anti-cancer | — | |
| Omega-3 (ALA) | 5.9g | — |
Based on Australian NRV. Source: FSANZ and USDA Food Composition Databases.
📈 Glycaemic index (GI)
💊 Key vitamins & minerals
✅ Health benefits
Mustard seeds contain glucosinolates — the same class of sulphur-containing phytochemicals that make broccoli, kale, cabbage and all Brassica family plants medicinally potent. When cells are damaged (by chewing or grinding), the enzyme myrosinase converts glucosinolates to isothiocyanates (including sinigrin → allyl isothiocyanate in brown/black mustard, and sinalbin → p-hydroxybenzyl isothiocyanate in yellow mustard). These isothiocyanates have demonstrated anti-cancer activity against breast, colon, lung, prostate and bladder cancer cell lines in extensive laboratory research, primarily via induction of Phase II detoxification enzymes and apoptosis. Regular Brassica family consumption is one of the most consistently cancer-protective dietary patterns in epidemiological research.
Mustard seeds provide 208µg of selenium per 100g — 378% of the daily requirement, making them one of the richest plant-based selenium sources after Brazil nuts. At typical culinary serving sizes (5–15g), mustard seeds contribute 10–25% of daily selenium — meaningful when accumulated over daily use. Selenium is essential for thyroid function, glutathione peroxidase antioxidant defence, DNA repair and immune cell function. The selenium in mustard is primarily in the organic selenomethionine form with high bioavailability.
Mustard seed oil contains significant alpha-linolenic acid (ALA omega-3) — approximately 5.9g per 100g of whole seed (or 5–11% of mustard oil depending on variety). Brown and oriental mustard varieties have higher ALA content than yellow. Regular use of mustard seeds and mustard oil as a cooking medium (common in Bengali, Kashmiri and Punjabi cooking) provides a meaningful plant-based omega-3 contribution that supports heart health and reduces the omega-6:omega-3 ratio in diets heavy in other cooking oils.
Mustard's characteristic heat comes from allyl isothiocyanate, which has a well-documented thermogenic effect — temporarily raising metabolic rate and heat production. This has driven research into mustard compounds for weight management. A small UK clinical trial found that consuming 5g of mustard seeds daily for 3 months was associated with meaningful metabolic benefits. The traditional use of mustard poultices for respiratory conditions and mustard baths for muscle soreness reflects the compound's vasodilatory and thermogenic properties.
⚠️ Who should limit or avoid
Mustard is classified as a major food allergen in the European Union, the UK and Canada — meaning it must be declared on food labels. Mustard allergy can cause anaphylaxis and is more prevalent than commonly recognised in Australia, where it is not yet in the mandatory declaration list. People who react to mustard condiment or spice should treat mustard seeds with the same caution as peanuts or tree nuts and read ingredient labels carefully. Mustard cross-reacts with other Brassica family plants in some individuals.
Mustard seeds (like all Brassica family plants) contain goitrogenic compounds that can interfere with thyroid iodine uptake in very large quantities. At culinary use levels (5–15g per meal), this is not a concern for people with adequate iodine intake. People with diagnosed hypothyroidism consuming very large daily quantities of mustard seeds or mustard oil should discuss with their endocrinologist, particularly if iodine intake is low.
The allyl isothiocyanate in brown/black mustard seeds (the compound responsible for the sharp, sinus-clearing heat) is a genuine mucous membrane irritant at high doses. Eating very large quantities of whole mustard seeds can cause gastric irritation, diarrhoea and oesophageal burning. Culinary amounts (up to 20g) are well-tolerated by most people. The heat is released by grinding and contact with water — whole toasted mustard seeds are much milder than ground or wet mustard.
🛒 How to source & use mustard seeds
Yellow/white mustard (Sinapis alba): largest, mildest heat, used in American yellow mustard, pickling, European whole-grain mustard. Lowest glucosinolate content. Brown mustard (Brassica juncea): medium size, much sharper and more pungent heat, used in Indian tadka (tempering), Bengali cooking, English and Dijon mustard. The most common variety in Indian grocery stores. Black mustard (B. nigra): smallest, most pungent, most traditional Indian variety — harder to find commercially as the plant shatters when harvested by machine. For Australian home cooking, brown mustard seeds from Indian grocery stores provide the best flavour-to-price ratio.
The fundamental Indian cooking technique of tadka (tempering) unlocks mustard seed flavour by frying whole seeds in hot oil until they pop and release their aroma. Heat 1–2 tablespoons of oil in a heavy pan until very hot. Add mustard seeds — they will sputter and pop loudly within 20–30 seconds. As soon as most seeds have popped and the popping slows, add other aromatics (curry leaves, dried chilli, onion). The popped mustard seeds add a nutty, slightly pungent base note to any dish. This technique is essential for South Indian dal, sambar, chutneys and vegetable dishes.
Home-made whole-grain mustard takes 5 minutes and is superior to commercial products. Soak 3 tablespoons yellow mustard seeds and 2 tablespoons brown mustard seeds in 80ml apple cider vinegar overnight. Add 1 teaspoon honey, 1/2 teaspoon salt. Blend to desired consistency (rough for whole-grain, smooth for Dijon-style). The flavour develops over 24–48 hours as glucosinolates convert to isothiocyanates. Store refrigerated for up to 3 months. The heat compounds are fully released by grinding and moisture contact — adjust water or vinegar for heat intensity.
🧊 Storage tips & shelf life
Whole mustard seeds are among the most shelf-stable spices — the intact seed coat protects the glucosinolates and oils from degradation. Store in a sealed glass jar away from heat and light. Quality check: crush a few seeds between fingers — they should release a sharp, pungent smell immediately. Seeds that have lost their aroma have lost most of their glucosinolate potency. Whole seeds keep far longer than ground mustard powder.
Ground mustard powder degrades far more rapidly than whole seeds — the glucosinolates become isothiocyanates on grinding (when moisture is added) and the volatile compounds dissipate. Store in a sealed container away from heat. The familiar sharp smell when mixing mustard powder with water confirms active glucosinolates are still present. Stale mustard powder has almost no heat or flavour.
Prepared mustard (condiment) is preserved by its acidity and salt content and keeps well. Refrigerate after opening to maintain flavour — unrefrigerated prepared mustard gradually loses its heat. Home-made whole-grain mustard: refrigerate and use within 3 months for peak flavour.
📖 About mustard seeds — complete guide
Mustard (Brassica juncea, B. nigra, Sinapis alba) is one of humanity's oldest cultivated plants, with evidence of use as food and medicine dating to at least 3000 BCE in the Indus Valley civilisation. The Sanskrit text Charaka Samhita (approximately 600 BCE) describes mustard in detail as a medical remedy. Mustard appears in the New Testament in the parable of the mustard seed (Matthew 17:20, Mark 4:30–32) — 'the kingdom of heaven is like a mustard seed, which is the smallest of all seeds on earth' — a passage reflecting the seed's cultural ubiquity in 1st-century CE Palestine. The Greek word for mustard (sinapi) and Latin (sinapis) are the origin of the genus name Sinapis for white mustard. Prepared mustard as a condiment was documented in ancient Rome — the recipe of mixing mustard seed paste with wine appears in the Roman cookbook Apicius. French Dijon mustard production began in the 14th century CE and remains the world's most prestigious prepared mustard category.
The global mustard market is driven predominantly by the condiment industry — prepared mustard is one of the world's highest-volume spice condiments by value after black pepper and chilli. Canada is the world's largest mustard seed producer (approximately 35% of global supply), followed by Nepal and Russia, with Australia as a significant secondary producer. The Dijon mustard industry in France imports most of its mustard seed from Canada and Eastern Europe, while the yellow mustard industry in the US sources primarily from domestic production (North Dakota, Montana). Australia's mustard seed production is centred in South Australia, Victoria and Western Australia, where it serves as a valuable break crop in wheat and barley rotations — fixing nitrogen, breaking disease cycles and diversifying farm income. Australian mustard seed is exported primarily to Europe for the food industry. The glucosinolate content of Australian-grown mustard seed is regulated — varieties with very high erucic acid content (from the oil fraction) are subject to food safety controls similar to those applied to early rapeseed varieties.