Mustard seeds have been used for their flavor and functional properties seemingly since the beginning of time. Mustard predates Biblical history and has long been enjoyed as a spice, herb, cooked vegetable and salad green. Its versatility lends itself to chefs and food scientists alike. These tiny seeds are all muscle. The hearty seed coat (bran) preserves the inner enzymes and oil. When mustard is cracked or ground, it can be used as a natural emulsifier, binder, antimicrobial and organoleptic ingredient. It’s also been used for medicinal aids and, as a cousin to canola, is even being explored for use as a biodiesel fuel.
Mustard is part of the Brassica genus, which includes cabbage, broccoli and Brussels sprouts. B. hirta and B. juncea yield three significant commercial mustard varieties: yellow, brown and oriental. The three seed varieties are cultivated in cool, temperate climate zones. Today, commercial crops are grown in the prairie providences of Canada, primarily Saskatchewan, with a much smaller volume in the United States in North Dakota and Montana.
Mustard seed is an annual crop with planting season in the spring and harvest at summer’s end through the beginning of fall. Unlike certain other commercial crops, mustard has never been genetically modified, making mustard a “family crop." The lower yields—compared to canola, especially GMO canola—are less desirable, thus family tradition is many times the deciding factor for farmers to plant mustard. Canada has set the precedent and is the world’s largest exporter of this crop. The United States is the largest importer, receiving more than half of Canada’s exported mustard seeds.
Not all mustard seed is created equally. Various grades have been established to differentiate the percentage of defective seed and dockage. Number 1 grade carries the highest quality. A number of factors contribute to the overall quality of the seed. These quality attributes cannot be modified, whereas dockage can be addressed with further separation of field stones, weed seed and other foreign material from the lot to improve the grade.
The appearance of mustard seed is most telling of the final quality once processed. Grading specialists look at the seed color, shape and surface texture. Green mustard seed is immature and can give an overall greenish hue to prepared mustard. Don’t be fooled, seed can appear to be mature on the outside yet still an immature green on the inside. The crush method has been developed to manage the accuracy in determining the percentage of green seed. Heat-, frost- and mold-damaged seed likewise underdeliver on the seeds' full functional potential.
What's inside
An oilseed, mustard is comprised of about one-third oil and is primarily differentiated by the flavor components from the oil present in the seed. Brown and oriental mustard seeds (B. juncea) contain sinigrin, a bitter glucoside. In contrast, sinalbin, another glucoside, is present in yellow mustard seed (B. hirta). These glucosides are enzymatically converted to isothiocyanates by myrosinase. It is the isothiocyanates that deliver the characteristic flavor of mustard.
The fierce pungency and strong aroma of brown and oriental seeds comes from the volatile oil, allyl isothiocyanante (AIT). AIT is stable, maintaining the spiciness of brown mustards well after manufacture. Yellow mustard loses its mild pungency quickly, as the formed p-hydroxylbenzyl significantly dissipates after only a couple of weeks. (To preserve mustard’s spiciness, keep it refrigerated; cold temperatures reduce the half-life of the compounds.)
Naturally occuring compounds in mustard’s oil serve as a natural antioxidant and preservative. Containing 93% allyl isothiocyanates, mustard oil helps to inhibit the growth of molds, yeast, Listeria, E.coli and several other foodborne pathogens. Mustard also stops the propagation of the free radical oxidation chains in much the same way as Butylated hydroxyanisole (BHA). Beyond adding heat and subtle flavor to foods, mustard serves as a functional ingredient. The seed coat (bran or hull) holds the binding power and is unique to B. hirta. Yellow mustard bran can hold up to 9 times its weight in water. The macromolecule arabinogalactan in mustard bran is also the major component of many gums, like gum arabic.
However, mustard mucilage exhibits thixotropic, or shear thinning, properties like xanthan gum. When paired with guar, locust bean or carboxymethylcellulose, mustard mucilage has a synergistic effect. What separates mustard as an ingredient choice from other gums is the mucilage’s ability to reduce surface tension and perform like gelatine, making mustard (the whole seed, as well as the bran on its own) a good choice for emulsified meat products, sauces and dressings.
In action
Prepared mustard first hit the map in the 13th century when Dijon France became the mustard capital of the world, and later a designated region. Dijon mustard is primarily made from the more-pungent brown and oriental mustard seed. It was not until 1904 that yellow mustard seed gained fame when the R.T. French Company debuted classic yellow mustard at the St. Louis World’s Fair. Today, French’s® Classic Yellow Mustard is the No. 1 brand in North America. These two well-known styles of mustard have very different flavor profiles, but originate from the same base principle of mixing ground mustard seed with a low-acid unfermented grape juice, called "must." The name "mustard" comes from the Latin mustum (must, or young wine) and adrens (burning).
Today, prepared mustards are made with water and vinegar in place of the must, but much of the traditional process still applies. Mustard can be manufactured from wet- or dry-milled formulas. The difference lies in the desired visual and organoleptic attributes. Wet-milled prepared mustards start with the whole intact seed and are freshly stone ground with the water and vinegar mix.
This process activates the inherent enzyme, myrosinase, in the seed to create the pungent heat, and releases the natural oil that gives mustard its glossy sheen. Mustard seed can be further processed as ground mustard, mustard flours and mustard bran. Prepared mustard can be made from ground mustard, but does not use the traditional stone-ground process. The ground mustard is simply mixed with the water and vinegar.
Mustard’s distinct flavor complements fatty foods and blends well with sweet ingredients, like honey, and a range of herbs, including dill, tarragon, basil and lavender. Mustard’s water-soluble heat compounds provide spiciness without the lingering heat, as with capsicum.
Sauces with mustard and other subtle flavors are wonderful on oily fish, as well as pork or beef that is well marbled or ground with a reasonable level of fat. Whether used topically on food, as part of a recipe, or as an ingredient in a new product, mustard’s flavor and functional properties far exceed its common name.
