Malt: A Practical Guide From Field to Brewhouse (Brewing Elements) by John Mallett

Author:John Mallett
Language: eng
Format: mobi
Tags: Brewing
ISBN: 9781938469169
Publisher: Brewers Publications
Published: 2014-12-08T08:00:00+00:00

Fig. 8.3: Diagram of barley kernel components. Illustration: Alexander Smith

The starchy endosperm can be up to 80 percent of total grain weight, making it the largest structure in mature barley kernels. The internal structure of the endosperm consists of a mixture of large and small starch granules embedded within a protein matrix. The large starch granules are about 25µ (microns, or 1/1000th of a millimeter) in size and contain about 90 percent of the starch in the grain. The smaller granules measure roughly 5µ in diameter, and account for the other 10 percent.

The barley embryo rests at the proximal end of the barley kernel. In the quiescent state, the embryo is quite small; only about four percent of the total weight of the grain. During hydration and subsequent germination, the embryo enzymatically breaks down the reserves contained within the endosperm, using the energy to generate the new plant tissue.

Despite being self-pollinating, reproduction in barley requires two separate fertilizations; the first for the formation of the embryo and the second to give rise to the aleuronic layer and starchy endosperm. Interestingly, the cells are triploid, meaning they have three sets of seven chromosomes; two from the mother and one from the father. The cells of the embryo and the resultant barley plant are diploid, with a total of 14 chromosomes.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.