MUSTARDS

Family: Cruciferae

Genera: Brassica, Sinapis

Species: B. juncea, B. nigra, S. alba (old syn. B. hirta)

(i) General background on the plant

Annual plants which are deep-rooted with slender taproots and erect stiff stems. Mustards reach 1-2 metres in height and bear a terminal inflorescence with axillary primary branching, and secondary and tertiary branching at lower plant populations. The flowering and podding is racemose, from the base of the racemes upwards, some 3-5 flowers opening each day for a 14-28 day period according to location. Flowers are 4-petaled, cruciform and bright yellow in colour, when they fall they leave a developing 2-valved linear siliqua. The siliqua of B. juncea, is smooth walled with 15-25 seeds in 2 rows, and that of S. alba, hairy and rough, with strongly veined valves and a pronounced flat veined beak, there are usually 5-8 seeds in the locules. Pollination by wind is invariably highly effective, with no need for bees

The most interesting usage of these species is for the production of their seeds as spice items, especially for the manufacture of condiments. They are amongst the oldest recorded spices in history (6000 BC), the largest volume spice in international trade, and unusual as a spice of temperate origin, produced fully by mechanical methods of agriculture. The tastes of mustards arises from sulphur-based essential oils from glucosinolates contained in the meal. As with most other cruciferous species, erucic acid is contained in significant amounts in the fixed oils of the seed.

For this usage, B. juncea in either its brown-seeded ("Brown") or yellow-seeded ("Oriental") forms is the predominant species contributing volatile, ie. nasal pungency, and S. alba ("White" or in N America "Yellow") contributes a mouth sensation of heat and sweetness. B. juncea replaced B. nigra in the 1950s as the plants of the latter species were dehiscent, so could not be mechanically harvested, and B. nigra is now very rarely grown and of no economic significance in the trade. Over 90% of world production of these species for condiment purposes is concentrated in the prairie provinces of Canada and just south of the border into N Dakota and Montana, where the crops benefit from long days, temperate conditions and large-scale fully-mechanised operations.

(ii) Details of quality characteristics

Seeds of B. juncea are, as above, either dark brown or golden yellow in colour, and have a mean diameter of 1.63mm, 408,000 seed per kg, whereas S. alba is yellow-buff, mean diameter 2.22mm. and 148,000 seed per kg. Both types are of fully rounded shape and high uniformity of size, which are important aspects for the milling operation; they are easily cleaned of most contaminants by standard equipment. Purity and cleanliness are of paramount commercial importance, and the presence of green or weathered seed, and of specific inseparable seeds such as rapeseed or wild mustard (S. arvensis) are the main causes of down-grading within the official grades of the Canadian Grain Commission, under which most world trading is conducted. Storage, handling and shipping are normally in large volumes of bulk, through elevator bins, rail cars and bulk shipping holds, with bulk lorries or barge cargoes in Europe. Below 10% moisture the seed is inert and not prone to infestation, but care must be taken with drying temperatures when reducing to this humidity, or enzyme damage may occur.

Gross composition of mustard seed

Ranges of variation in contents of common fatty acids in fixed oils

(Variations under genetic control have been identified, but are not utilised as they appear to have deleterious effects on condiment product quality.)

(iii) Current production and yields

The North American prairie provinces annually average 170,000-200,000 ha of mustard cropping for condiment purposes, producing some 140,000 tonnes with an export value of $US 38-40 million. Yields are of the order of 1200-1500kg/ha of B. juncea and 600-950 kg/ha of S. alba. European production in Hungary, Poland, Eastern Germany and England total annually 10-15000 tonnes. Other production in Argentina, Australia, Balkan countries, Sweden, France and Italy is on a smaller, local scale, and does not enter world trade.

Where B. juncea is grown as an oilseed crop for edible oil, it is often as a part of a total rapeseed/mustard cropping; the total production of mustard in India has been of the order of 4.5 million tonnes. Production in Pakistan and Bangladesh is not quantified, but in recent years Bangladesh has also been importing 40-70,000 tonnes of B. juncea annually from Canada for expelling. The total for the small scale domestic acreages in China is not known, but Southern Ukraine annually grows 100,000 tonnes for local consumption. Meals after the expelling have a high glucosinolate content and may require steam treatment before feeding to livestock.

(iv) Constraints

The only constraint to increased European production is to attain seed at a value and quality to match the relatively cheap bulk-produced North American produce, despite the higher yields in Europe with its longer season of growth. There are no legislative restrictions, nor are there any support payments applicable to mustard seed. The preponderant part of world production of mustard seed is under contract to trading companies who clean, dry, grade, sell and ship, or in some cases contracted direct to condiment manufacturers, so that it is wise to make clear arrangements for disposal of the crop before sowing. This includes the choice of the appropriate variety for local adaptation and for the quality needs of the ultimate user for his processing and products.

B. juncea easily cross-pollinates with other Brassica species, it therefore requires isolation when grown for seed.

(v) Markets and market potential

As an edible oilseed, the scope for B. juncea world usage is limited only by its value against that of rapeseed/canola, at somewhat higher oil contents. Recent work in Canada and Australia seems to be developing an "oilseed juncea mustard" with oil and meal quality to match canola, able to be grown in drier areas of land.

Growth of demand for mustard seeds for condiment manufacture has been sustained at 3-4 % annually over many years. A part of this is into condiment products, but also the flour of S. alba is a valuable food ingredient, in sauces, ketchups and mayonnaises, where in addition to flavour, colour and mild preservative action it also acts as an emulsifying agent and stabiliser. There is growing demand also for flour, crushed or ground seed of S. alba in which the enzyme myrosinase has been inactivated as a taste-free inclusion in other prepared foods and especially as an additional source of protein (30%) in products of the processed meat industry in North America.

B. juncea is also grown extensively in the Indian subcontinent, China and the Ukraine as an oilseed for edible oil as its seeds have oil contents in excess of 40%, there is also some usage as a salad leaf, as a cooked vegetable and as fodder. S alba is rarely used for oil production, as its content in the seed is only of the order of 30%, but its oil has the attraction of a high-erucic acid content 40-50% if this is required for the use of the oil as a plasticiser or industrial lubricant.

The mucilage in the seedcoat of S. alba is currently of increasing interest as besides its value in stabilising condiments and other prepared foods, it has been found to have unique other properties, but specific outlets have not yet been established.

(vi) Other information

Mustards are planted and harvested similarly to oilseed rape and are spring sown arable crop plants which fit in well as breaks in cereal rotations, without any need for specific machinery. The mustards do not normally require additional P or K fertilisation but are very responsive to added nitrogen. Adequate magnesium is necessary, but no other trace elements or sulphur addition seem to be needed. Most soil types are suitable except the heaviest of clays, on which it may be difficult to attain a sufficiently fine firm seedbed in the spring.

The plant populations and row spacings are very elastic, with little effect on yields. In Europe with a season March to early September, crop yields are more than double those in north America, where the season is restricted only May - August. Neither species is affected by light frosts, B. juncea is drought tolerant, and both will withstand rough preharvest weather without dehiscing.

Neither species is prone to high losses to insect pests and they are very rarely affected by plant diseases. Adequate herbicides are cleared for safe usage, without residue problems.

Breeding of varieties of B. juncea for enhanced yield and oil content has proceeded in India, Pakistan and China. For condiment, the ranges of varieties produced at the principal breeding centres of Colmans of Norwich, UK and AgCanada Research Centre, Saskatoon, Canada of both types of mustard, have given higher crop yields and full mechanisation, and include varieties with particular processing attributes such as lower contents of seed hulls and fixed oils, higher essential oils, proteins and seed mucilage content (in S. alba).

(vii) Contacts

The IENICA project gratefully acknowledges contribution of this information from John Hemingway, Consultant in Speciality Crops.

John S Hemingway Consultancy, 18 Postwick Lane, Brundall, Norfolk, NR13 5LR. UK. Tel & fax: + 44(0)1603 713154

AgCanada Research Centre, 107 Science Place, Saskatoon, S7N OX2. Canada. Tel: + 1 306 956 7200, Fax: + 1 306 956 7247

Mustard Association, c/o United Grain Growers, Box 6600, Winnipeg, R3C 3A7. Canada. Tel: + 1 204 944 2224 Fax: + 1 204 947 1779

Richard Zoellner GmbH & Co, Moorfleeter Deich 131, 2000 Hamburg, Germany. Tel: + 49 407 891 7113, Fax: + 49 407 891 7117

van Gelder/de Jong Pz, Oostzijde 193, 1500 BD Zaandam, The Netherlands. Tel: + 31 75 631 1211, Fax: 75 670 1570

Springdale Crop Synergies Ltd,
Mr Clifford Spencer, Springdale Crop Synergies Ltd, Rudston, Driffield, East Yorkshire, YO25 4DJ
Telephone: +44 (0) 1262 421100
Website: www.springdale-group.com

(viii) References

ISO Standard 1237-1981 (E) UDC 633 844 0041

Mustard Association (1996) Mustard Growers Manual

Colmans of Norwich (1988) Mustard Seed Crop Husbandry

Cui, W; Eskin NAM; Billiaderis, CG (1993) Chemical and physical properties of yellow mustard mucilage. Food Chemistry, 46, 169-176.

Hemingway, JS (1976 and 1995) Mustards. In Simmonds NW and Smart J (eds) Evolution of Crop Plants. Longman, London. pp82-86

Hemingway, JS (1993) Mustard and Condiment Products. In Encyclopedia of Food Science, Food Technology and Nutrition, Academic Press, London. pp 3178-3182.

Hemingway, JS (1995) The Mustard Species: Condiment and Food Ingredient Use and Potential as Oilseed Crops. In Kimber D and McGregor DI (eds) Brassica Oilseeds, Production and Utilisation. CAB International, Wallingford, UK. pp 373-383.