Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2006
Publication Date: 1/1/2007
Citation: Moreau, R.A., Flores, R.A., Hicks, K.B. 2007. The composition of functional lipids in hulled and hulless barley, in fractions obtained by scarification and in barley oil. Cereal Chemistry Vol 84, No. 1, p.1-5.
Interpretive Summary: Barley kernels have been reported to contain several types of nutraceutical compounds that have health-promoting properties. These include two types of "functional lipids", phytosterols, which can lower serum cholesterol and tocopherols and tocotrienols, which are vitamin E analogues that are potent antioxidants and are thought to be important for cardiovascular health. Most barley that is used in food products is "pearled" or "scarified" to abrade and remove the fibrous hull, which improves the flavor and also creates pearled kernels that are enriched in starch, protein, and other nutrients. In this study we measured the levels of functional lipids in barley kernels and "abraded outer layers" removed by the scarifying process. The levels of tocopherols and tocotrienols in the recovered outer layers of the kernel were probably not high enough to justify their use directly as functional foods. However, the levels of both compounds in the "barley oils", obtained by extracting kernels or the recovered outer layers of the kernel, were sufficiently high to possibly justify the development of barley oils as new functional foods. In addition, because the levels of extractable oil is high (7-9%) in the abraded outer layers of two barley cultivars (Doyce and Merlin), obtaining barley oil from these milling products could be an economical process. These studies indicate the unique chemical composition of barley oil and the possibility of obtaining it by extracting abraded outer layers of kernels. These facts both suggest that barley oil could be developed into a valuable new functional food product that would benefit the health of consumers. This work also would benefit barley growers and new farmer cooperatives who are using barley as a feedstock for fuel ethanol production. Recovery and marketing of valuable nutraceutical co-products from a barley-to-ethanol plant would bring more revenue to the company and result in overall lower costs for the production of fuel ethanol.
Technical Abstract: Two cultivars of hulled barley (Thoroughbred and Nomini) and two cultivars of hulless barley (Doyce and Merlin), were scarified to abrade the outer layers of hull and/or pericarp. The resulting fine fractions were evaluated as potential sources of functional lipids (phytosterols, tocopherols and tocotrienols). The levels of total phytosterols and total tocotrienols in the barley scarification fine fractions were probably not high enough to justify their use as functional foods. However, the levels of total phytosterols and total tocotrienols in the oils prepared from both whole kernels and scarified fines were both sufficiently high to make it reasonable to consider their potential use as new "functional oils." Indeed, the levels of total tocotrienols in barley oils (2911 to 6126 mg/kh oil) are several-fold higher than those reported to occur in two other oils that are being marketed as "high in tocotrienols" - palm oil (530 mg/kg) and rice bran oil (770 mg/kg). The levels of total phytosterols in barley oils are also sufficiently high (0.18 to 1.44 g/15 g oil) to significantly lower LDL-cholesterol at reasonable dosages of 15 ml/day (1 tsp/day).