Cereals & Grains Association
Log In

Lipase Activity and Lipid Metabolism During Oat Malting

January 1999 Volume 76 Number 1
Pages 159 — 163
David M. Peterson 1

Department of Agronomy, University of Wisconsin-Madison, and Cereal Crops Research Unit, Agricultural Research Service, USDA, 501 Walnut St., Madison, WI 53705, and Phone 608/262-4482. Fax 608/264-5528. E-mail: dmpeter4@facstaff.wisc.edu Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by USDA implies no approval of the product to the exclusion of others that may also be suitable.

Go to Article:
Accepted October 16, 1998.

Experiments were conducted to determine the relationship, if any, between lipase activity and the metabolism of lipids during malting (germination) of oat (Avena sativa L.) seed. During the course of malting, concentration of the free fatty acid fraction increased markedly at the expense of the neutral lipid fraction (predominantly triacylglycerides), while the initially high lipase activity (most of which is located in the surface layers of the grains) decreased by ≈40%. The fatty acid compositions of total and neutral lipid fractions were stable during malting, but there were marked changes in the free fatty acid and phospholipid fractions. In a comparison among 12 hulled and hull-less genotypes, there were no significant regressions between the quantitative changes in lipid fractions and lipase activities. Brief treatments with chemicals or hot H2O that partially or completely inhibited lipase activity had various effects on subsequent quantitative changes in lipid fractions, but these changes were not consistent with the inhibitions in lipase activity observed. It was concluded that the degradation in triacylglycerides and increase in free fatty acids observed during oat malting were not controlled by the level of total lipase activity. Rather, it was suggested that oat may have another lipase present in the cells where the oil bodies are located that hydrolyzes triacylglycerides from the oil bodies during germination. Further research is needed to substantiate this hypothesis.

This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. American Association of Cereal Chemists, Inc., 1999.