Chapter 11 - Cold pressed amaranth (Amaranthus tricolor) oil

Abstract

The amaranth plant is a resistant, fast-growing pseudocereal that was used as the main crop by the Aztecs in Mexico, and cultivated by other Mesoamerican civilizations. Amaranth is rich in fiber, magnesium, calcium, protein, and lysine. It is a productive crop with nutritious potential for both developing and industrialized countries. In addition, amaranth seeds contain approximately 5.7%–9% oil, showing a high degree of unsaturation. This oil contains 25% oleic acid, 50% linoleic acid, and 1% linolenic acid. Other reported lipid fractions are phospholipids, glycolipids, sterols, and squalene. Amaranth oil contains between 6% and 11.2% squalene, considerably more than the amount in other cereal oils, and is a 30-carbon polyunsaturated, triterpenic hydrocarbon (2,6,10,15,19,23-hexamethyltetracosa-2,6,10,14,18,22-hexaene) with various valuable nutritional, cosmetic, pharmaceutical, and medical applications. Amaranth oils have been shown to possess multiple advantages, such as superior antioxidant, nutraceutical, antiaging, antiinflammatory, antimicrobial, and emollient properties. Most plant oils are obtained by mechanical pressing or by chemical extraction with organic solvents. Nonetheless, chemical solvents and application of heat are generally used to extract oil from seeds, but trans-fatty acids are generated during this process. In order to avoid the use of toxic solvents like hexane and exposure of the oil to high temperatures for long periods, “green extraction technology” is currently preferred, such as cold pressing, supercritical fluid extraction, and ultrasound-assisted extraction, among others. Oils extracted in this way are characterized by a higher content of native substances than refined oils.