The chemical composition of oats I. The oil and free fatty acid content of oats and groats

Abstract

The petroleum-ether extractable oil content of native oats (dry-weight basis) ranges 3·0–8·5%, and is chiefly dependent upon variety and kernel content (which is itself a varietal characteristic). That of the kernel, which comprises 64–81% of the grain by weight, is 4–11% with a spread of about 2·5% within the variety. The kernel contains in addition about 2·5% of more complex insoluble fatty material which is released on acid hydrolysis. The husk, on the other hand, contains only a few tenths of one per cent of petroleum-ether soluble oil together with about 1% of more complex material that can be released by acid hydrolysis. Certain environments favour higher levels of oil content within all varieties whereas others favour lower levels; Scottish samples tend to be slightly higher in oil content than English samples of the same variety. The free fatty acid content of the oil in the kernel ranges 3–10% for sound, viable grain; the value for any sample is more dependent on environment during cultivation, harvest and storage than on the variety. After the grain is milled or pulverized the free fatty acid content rises to much higher levels within a few days.