Cereals processing technology

88 Cereals processing technology
When rapid results are needed, properly calibrated electronic moisture meters
are sufficiently accurate for most control work.
Color and milling requirements
For milled rice, United States Standards for Rice (Table 5.4) specifies:
US No. 1 grade shall be white or creamy, and shall be well milled. US
No. 2 may be slightly gray, and shall be well milled. US No. 3 may be
light gray, and shall be at least reasonably well milled. US No. 4 may
be gray or slightly rosy, and shall be at least reasonably well milled. US
No. 5 and No. 6 may be dark gray or rosy and shall be at least slightly
milled.
Degree of milling
Extent of bran layer and germ removal from the endosperm is referred to as
degree of milling. United States Standards for Rice (Table 5.4) specifies three
degrees of milling: well milled, reasonably well milled, and lightly milled.
Dockage
According to United States Standards for Rice (USDA, USDA 1982 with
changes 1982–1990): 30,31
dockage shall be any matter other than rice which can be readily removed
from rough rice by use of appropriate sieves and cleaning devices,
and underdeveloped, shriveled, and small pieces of kernels of
rough rice removed in properly separating dockage and which cannot be
recovered by properly rescreening and recleaning.
Other impurities difficult to remove because of size, shape, and density similar
to rice are classed as objectionable materials, including glass fragments and
certain weed seeds.
Damaged kernels
United States Standards for Rice 31 defines damaged kernels as whole or broken
kernels of rice which are distinctly discolored or damaged by water, insects,
heat, or any other means, and whole or large broken kernels of parboiled rice in
nonparboiled rice.’ ‘Heat-damaged’ kernels are defined as whole or large broken
kernels of rice which are materially discolored and damaged as a result of
heating, and whole or large broken kernels of parboiled rice in nonparboiled rice
which are as dark as, or darker in color than, the interpretive line for heatdamaged
kernels. 30,31 Visual inspection by trained inspectors is the only reliable
method available for determining amounts of damaged kernels in rice.
Odors
Off-odors in rice severely affect grade. 31 Rice that is musty or sour, or that has
any commercial objectionable foreign odor, shall be graded US sample grade.
According to the Rice Inspection Handbook (USDA 1982 with changes 1982–