Cereal Chem 61:105 - 108. | VIEW
Lipase Activity in Oats During Grain Maturation and Germination.
A. A. Urquhart, C. A. Brumell, I. Altosaar, G. J. Matlashewski, and M. R. Sahasrabudhe. Copyright 1984 by the American Association of Cereal Chemists, Inc.
Lipase activity (glycerol tri[l-14C]oleate hydrolysis) was assayed in developing oat (Avena sativa L.) grains from 2 to 44 days postanthesis. In three cultivars (Hinoat, Sentinel, OA 424-1), activity was detected throughout kernel development. On a dry weight basis, a first peak of lipase activity was found during the first nine days postanthesis in all three cultivars. Sharp drops in activity per gram, reflecting rapid changes in kernel dry weight, followed. A second peak occurred at 23 days (Hinoat) and at 30 days (Sentinel, and OA 424-l). Lipase activity per 100 kernels increased as the grains matured, and reached maximum levels between 23 (Hinoat) and 30 days (Sentinel and OA 424-l). Peaks of activity coincided with maximum fresh and dry weights. Activity declined as the grains dried to harvest maturity. Final activities were 11.1 (Hinoat), 14.8 (Sentinel), and 3.4(OA 424-1) micro-mol/min per 100 grains; final levels per gram of dry weight were 5.0, 7.6, and l.1 micro-mol/min g, respectively. OA 424-1 had significantly lower levels. In Hinoat grans, classified into six groups of uniform developmental stage, lipase activity per 100 kernels was maximum in late dough, but was moderately high in milky and early dough stages. During germination of Hinoat, a 60% increase in activity occurred in the first 12 hr following the start of imbibition. Activity in the embryo, negligible at 24 hr, increased during the next three days. Activity in the rest of the kernel decreased gradually.