Salvia hispanica (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

Salvia hispanica L.

Protologue: Sp. pl.: 25 (1753).

Family: Labiatae

Chromosome number: 2n= 12

Kiosmina hispanica (L.) Rafin. (1836), Salvia chia Sessé & Moc. (1893), S. schiedeana Stapf (1896).

• Chia (En). Chia (Fr)
• Indonesia: cuwing, salasi huma (Sundanese).

S. hispanica originates from southern Mexico and northern Guatemala. Its earliest cultivation and utilization was by the Aztecs in Central America. It was introduced and naturalized in the West Indies, Spain and West Java. It is grown commercially in central Mexico, Guatemala, United States (southern California, south-eastern Texas), northwestern Argentina and occasionally in West Java, Peninsular Malaysia and Singapore.

The oil obtained from the seed of S. hispanica is used in cooking, cosmetic preparations and, as it is a drying oil, in the industrial production of paints, varnishes and lacquer work. Traditionally the oil is utilized in Mexican lacquer work and as overgloss protection for paintings. The presscake is suitable as human food and animal feed.

Since pre-Columbian times the people of Central America have consumed S. hispanica seeds as food and medicine. The seed is also a source of a mucilaginous polysaccharide gum. When water or juice is added to the seeds, a gel-like preparation is produced which is nutritious and filling. In Mexico parched ground seed sometimes mixed with maize flour is made into loaves. Ground seed is also mixed with orange juice to make a breakfast drink, while in West Java it is made into a drink that is used as a substitute for "selasih", a drink made from Ocimum basilicum L. Seeds have also been used as thickening material e.g. in sauce preparation. The seeds are very nutritious and it is said that a teaspoonful would sustain a person on a forced march for 24 hours. The high content of anti-oxidants makes the seed a possible source for their commercial extraction. In herbal medicine chia seed is taken to adjust the secretion of bile particularly after emotional stress and as a remedy for constipation. Chia leaves contain an essential oil which is potentially useful in the production of flavours and perfumes and to reduce insect attack and damage in stored goods. S. hispanica has gained some importance as an ornamental in the United States. The seeds are placed on the surface of clay figurines. When wetted they germinate, covering the object with a coat of hairy sprouts.

Production and trade of chia seed is locally important in America but statistics are not available. In Mexico seeds are for sale in markets.

Per 100 g, the seed of S. hispanica contains: protein 23 g and fat 25-39 g. The oil is clear, does not turn yellow with time; its iodine value is 198. Its lipid fraction is composed of neutral lipids 97%, glycolipids 2% and phospholipids 1%. The fatty acid components are linoleic acid 17-26%, linolenic acid 50-57%, and small amounts of palmitic acid and oleic acid. For the glycolipids and the phospholipids the dominant fatty acids are palmitic acid and linoleic acid.

As the content of unsaturated fatty acids in the seeds is high, they also contain a relatively large amount of anti-oxidants, including flavonols, caffeic acid and chlorogenic acid. Caffeic acid is a potential anti-oxidant for foodstuffs because it has no mutagenic effect.

The mucilaginous gum of chia is contained in large cells in the seed coat. When placed in water these cells swell rapidly absorbing 5-6 times the weight of the seed in 3 minutes. The gum consists of long polysaccharide chains that comprise β-D-xylose, α-D-glucose and 4-0-methyl-α-D-glucuronic acid in a ratio of 2:1:1.

In the essential oil from chia leaves, 52 components have been identified. Major components are β-caryophyllene, globulol, τ-muurolene, β-pinene, α-humulene, germacrene-B and widdrol. The composition of the essential oil varies with growing area, climate and post-harvest handling of the leaves.

Erect or ascending herb, 0.5-1 m tall or more; stem and branches quadrangular, villous and hispid. Leaves opposite, thin; petiole slender, 1-6 cm long; blade oblong-lanceolate to ovate, 3-8 cm × 1-4.5 cm, base obtuse and abruptly attenuate, margin entire at base and elsewhere serrate or serrulate, apex acute or acuminate, both surfaces pubescent. Inflorescence consisting of verticillasters of 6-10 zygomorphic flowers, these congested in a dense, terminal false spike 5-25 cm × 1.5 cm; internodes 2-5 mm long; bracts ovate-acuminate, 6-8 mm long, persistent; calyx tubular but 2-lipped, slightly inflated below, 6-8 mm long, in fruit 8-11 mm, densely pilose, upper lip strongly keeled, sharply pointed, lower lip 2-toothed; corolla tubular, 2-lipped, blue or purplish-blue, the lips shortly exposed, tube 4.5-5.5 mm long, upper lip rounded, 3 mm long, sericeous outside, lower lip 3-lobed; 3.5-5 mm long; stamens 4, didynamous, hardly exposed, lower pair fertile, lower connective branch swollen; disk prominent; ovary superior, style 2-branched, upper branch long and slender, 2.5 mm long, pointed, lower one short, club-shaped; the main style articulate above the base. Fruit consisting of 4 schizocarpous nutlets, each one ellipsoid, 1.8 mm long, mottled with black and grey.

The growing period of S. hispanica is 4-6 months. In the United States it is grown as a summer annual. It is sown and germinates during the warm days of late spring, flowers during the shorter days of September and produces seed that matures in the autumn. In West Java it bears flowers the whole year. The flowers are much visited by bees. When the seeds ripen, the plant loses its leaves and fields then look much like those of sesame.

Salvia L. comprises about 500 species, widely distributed in temperate and subtropical areas, but less so in the tropics. About 20 species occur in South-East Asia, of which 1 is truly native, 5 are naturalized and 14 others occur only in cultivation mainly as ornamentals. A small group of Salvia species and the closely related Hyptis suaveolens (L.) Poit. are known as "chias". They all occur in the drier parts of Mexico and include, in addition to S. hispanica , the summer annuals H. suaveolens ("chia grande", "chan" or "conivari") and Salvia tiliaefolia Vahl (mostly a weed, but seeds are occasionally collected), and the winter annuals S. columbariae Benth. ("California chia" or "golden chia") and S. carduacea Benth. ("thistle sage"). In the United States the summer chias flower in late summer and produce seed in late autumn, the winter chias set seed in summer.

In its natural area, S. hispanica grows in moist or dry thickets, in open, often dry rocky slopes, sometimes on sandbars along streams and often as a weed, at altitudes 1150-2500 m. In West Java it can be found in open areas, road sides, fallow or weedy agricultural land and low brushwood at altitudes of 900-1700 m. In north-western Argentina it is grown at elevations of 300-1350 m, with maximum temperatures of about 30°C and minimum temperatures of 12.5°C. Rainfall in this region varies between 100-1000 mm per year. This is a species for the semi-arid areas.

S. hispanica is grown from seeds. The germination rate of good seed averages 98%, declining to 75% after 1 year. The seed rate is about 6 kg/ha. The seeds are sown in rows that are 70-80 cm. apart.

In commercial farms in north-western Argentina nitrogen fertilizer is applied at a rate of 25-50 kg/ha. S. hispanica is occasionally irrigated.

Few diseases and pests seriously affect S. hispanica . Charcoal rot ( Macrophomina phaseolina ) occasionally causes damage.

S. hispanica is harvested manually or with a modified combine harvester. In north-western Argentina, hand-harvesting gives higher yields than combine-harvesting.

Commercially grown S. hispanica in north-western Argentina yields an average of 540-600 kg seed per ha, although it can be as high as 1600 kg/ha. In Mexico, 1000-3000 kg/ha are obtained.

The oil of S. hispanica is obtained from the ground seed by heating and solvent extraction.

A few germplasm collections of S. hispanica exist, but the number of accessions is very limited. Breeding programmes are not known.

Interest in the oil of S. hispanica is growing both as a highly unsaturated food oil and as a non-yellowing, drying oil for varnishes and lacquer work. The current interest in traditional products and techniques is likely to strengthen this trend. Programmes have been established to expand production of S. hispanica in Argentina, while in the United States it is one of the crops promoted to diversify agriculture. There are no indications, however, that it will become more important in South-East Asia.

• Ayerza, R., 1995. Oil content and fatty acid composition of chia (Salvia hispanica L.) from five northwestern locations in Argentina. Journal of the American Oil Chemists Society 72: 1079-1081.
• Bushway, A.A., Wilson, A.M., Houston, L. & Bushway, R.J., 1984. Selected properties of the lipid and protein fractions from chia seed. Journal of Food Science 49: 555-557.
• Coates, W. & Ayerza, R., 1996. Production potential of chia in northwestern Argentina. Industrial Crops and Products 5: 229-233.
• Gentry, H.S., Mittleman, M. & McCrohan, P.R., 1989. Introduction of chia and gum tragacanth in the U.S. In: Janick, J. & Simon, J.E. (Editors): Advances in new crops. Timber Press, Portland, Oregon, United States. pp. 252-256.
• Keng, H., 1978. Labiatae. Salvia. In: van Steenis, C.G.G.J. (Editor): Flora Malesiana. Series I, Vol. 8(3). Sijthoff & Noordhoff International Publishers, Alphen a.d. Rijn, the Netherlands. pp. 356-360.
• Lin, K.Y. & Daniel, J.R., 1994. Structure of chia seed polysaccharide exudate. Carbohydrate Polymers 23: 13-18.
• Mukhtar Ahmed, Ting, I.P. & Scora, R.W., 1994. Leaf oil composition of Salvia hispanica L. from three geographical areas. Journal of Essential Oil Research 6: 223-228.
• Silvia Taga, M., Miller, E.E. & Pratt, D.E., 1984. Chia seeds as a source of neutral lipid antioxidants. Journal of the American Oil Chemists Society 61: 928-931.
• Standley, P.C. & Williams, L.O., 1970. Flora of Guatemala. Labiatae. Salvia. Fieldiana, Botany 42, part A: 273-301.
• Whistler, R.L., 1982. Industrial gums from plants: guar and chia. Economic Botany 36: 195-202.

B.E. Umali & L.P.A. Oyen