Use of microscopy to assess bran removal patterns in milled rice |
| |
| Authors: | Wood Delilah F Siebenmorgen Terry J Williams Tina G Orts William J Glenn Gregory M |
| |
| Institution: | Agricultural Research Service, United States Department of Agriculture (USDA), Western Regional Research Center, Albany, California 94710, United States. de.wood@ars.usda.gov |
| |
| Abstract: | During rice milling, the bran and germ are successively removed from the caryopsis (kernel). Because bran and germ contain large quantities of lipid, the amount of lipid remaining on the kernel surface may be used as a method for the assessment of milling quality. Bulk samples of rice pureline varieties and an experimental hybrid were milled for 0, 10, 20, 30, and 40 s. Scanning electron microscopy (SEM) revealed that brown rice kernels had large contours of linear protuberances and depressions running lengthwise along the kernel surface. The protuberances were abraded successively during milling, but varying amounts of material remained in the depressions. Light microscopy combined with the lipid-specific probes Nile Blue A or Sudan Black B demonstrated that the material in the depressions observed with SEM was lipid. Sections of whole, milled rice kernels, prepared using a modified sectioning technique and stained with Nile Blue A, showed that portions of the embryo remain after milling and that lipid is located on or near the surface of the kernel. Differences in quantity and distribution of residual lipid as milling duration increased were documented photographically to indicate the extent to which the bran and embryo components were removed during milling. This paper provides proof of concept that residual lipid is a robust measure of the degree of milling. |
| |
| Keywords: | |
| 本文献已被 PubMed 等数据库收录！ |
|
