CHIA SEEDS: NEW SOURCE OF OMEGA-3 FATTY

ACIDS, NATURAL ANTIOXIDANTS, AND DIETETIC FIBRE

Ricardo Ayerza (h) & Wayne Coates

Southwest Center for Natural Products Research & Comercialization

Office of Arid Lands Studies, The University of Arizona

(31/7/01)

EXTENDED SUMMARY

           Modern science has determined that chia seeds contain oil amounts varying between 32-39%, with the oil offering the highest natural percentage of α-linolenic acid known (60-63%) (Table 1). This essential fatty acid also has been shown to be of significant importance in a great number of industrial compounds such as varnish, paints, cosmetics, etc.

           Chia has been shown to hold significant potential in the food industry. It must be emphasized that an α-linolenic fatty acid is an unsaturated ω-3 fatty acid. Polyunsaturated fatty acids like α-linolenic are very important to human nutrition, but they must be supplied in food since they cannot be synthisized in the body. Oils containing a high amount of ω-3 fatty acids in the diet have been shown to reduce the risk of cardiovascular diseases.

           Alpha-linolenic fatty acid in the human body acts as a substratum for the transformation into DHA and EPA through the action of desaturation and elongation enzymes. Even though the conversion of α-linolenic acid into DHA and EPA has long since been determined, the mathematical relationship of ω-6 and ω-3 18-carbon fatty acids in the conversion to thier respective 20-carbon metabolites in the tissues has only been recently reported. In 1995, research projects funded by the Australian National Health and Medical Research Council showed that a higher content of α-linolenic acid in the diet increased the EPA content in human tissues in a predictable manner. A linear relationship was determined between the incorporation of vegetable based α-linolenlc acid and the EPA concentrations in plasma and cellular phospholipids. Also, research published in 1997 by the American Society for Clinical Nutrition which compared the effects of supplying vegetable based α-linolenic fatty acids with marine based DHA and EPA fatty acids in terms of the hemostatic factors in humans could not be proven to be statistically different

           Chia possess the highest percentage of the polyunsaturated fatty acids, α-linolenic and linoleic (i.e. 83.2%), of all crops. This is followed by safflower and sunflower, with 75% and 67% respectively. This difference is even more significant if one considers that safflower and sunflower lack α-linolenic acid. Rapeseed oil also offers a high degree of unsaturation (67%), but this arises because of a high oleic (monounsaturated) acid content, giving it a relatively low content (27%) of polyunsaturated fatty acids.

           Chia seed possesses 19-23% protein. This percentage compares favorably with other nutritional grains such as wheat (14%), corn (14%), rice (8.5%), oats (15.3%), barley (9.2%), and amaranth (14.8%). Unlike other grains, however, the amino acids of chia protein (Table 2) have no limiting factors in the adult diet. Other grains are limited in terms of two or more amino acids.

           Chia seed also is a good source of B vitamins (Table 3), calcium, phosphorus, potasium, zinc, and copper (Table 4).

           Water and methanol extracts of chia seed which has been pressed and the oil extracted have demonstrated a strong antioxidizing activity. The most important antioxidants are chlorogenic acid, caffeic acid, myricetin, quercetin and kaempferol flavonols (Table 5). The antoxidative, antiplatelet aggregation, anti-inflammatory, antimutagenic, anticarcinogenetic, and antiviral activities of flavonols have been demostrated in vitro. Epidemiological studies indicate that high level of consumption of flavonol-rich foods and beverages may protect against CHD , lung cancer, and stomach cancer.

           Since oxidation in chia is minimal to non-existant it holds great potential within the food industry compared to other α-linolenic fatty acid sources such as flax, which exhibit rapid decomposition due to a lack of antioxidants. Flax also contains toxic cyanoglycosides and a vitamin B6 antagonist compounds. Recent scientific findings shows that low blood levels of B vitamins are linked with an increased risk of fatal coronary heart disease and stroke.

           Once the oil has been extracted from chia seed, the material that remains contains 50-60% fiber. The seed possesses 5% soluble fiber, which appears as mucilage when it is placed in water, and is useful as a dietary fiber. The importance of chia then is not only from its nutritional value, but also because of its "thickening nature" which is important within the cosmetology industry, and for other applications.

           Chia biomass also has an abundance of essential oils which are of significant commercial importance in the flavors and fragrance industries. Of 52 different components detected, the dominant ones are: β-caryophyllene (13.3 - 35.7%), globulol (12.8 - 23.4%), γ-muurolene (4.4 - 17.6%), β-pinene (2.5 - 15.1%), α-humulene (3 - 6.1%), germacrene-Β (1.8 - 5%), and widdrol (1.3 - 2.4%); and in lesser amounts: β-Bourbonene, linalool, valencene, and τ-cadinol.

TABLES REFERENCES

1) Ayerza, R.(h), 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(9) 971-1090.

2) Ting, I.P., J.H. Brown, H.H. Naqvi, A. Estilai, J. Kummamoto, and M. Matsumura. 1990. Pages 197-202 in: H.H. Naqvi, A. Estilai, and I.P. Ting, eds., New Industrial Crops and Products. The University of Arizona and The Association for The Advancement of Industrial

3) Bushway, A.A., P.R. Belya, and R.J. Bushway. 1981. Chia seed as a Source of Oil, Polysaccharide, and Protein. Journal of Food Science, 46:1349-1356.

4) Taga, M.S., E.E. Miller, and D.E. Pratt, 1984. Chia seeds as a source of natural lipid antioxidants. Journal of American Oil Chemists' Society, 61:928-931.

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