Agriculture Reference
In-Depth Information
underdeveloped kernel are also very important for assessing the quality of rice. An
inspector usually evaluates visually the components of the rice as an official inspec-
tion when brown rice is shipped after hulling.
An automatic method to measure protein content, moisture content, and percent-
age of sound whole kernel rice has been developed in order to grade rice upon receiv-
ing the rough rice and on shipping of brown rice according to the quality criteria
(Kawamura et al., 2003). Figure 14.2 shows a flowchart of an automatic rice quality
inspection system. The system consists of a rice huller (an impeller-type huller), a
rice cleaner (a thickness grader), an NIR instrument, and a visible-light (VIS) seg-
regator. Many researchers have reported that the precision and accuracy of the NIR
instrument and the visible-light segregator are sufficiently high to enable accurate
classification of rice (Delwiche et al., 1996; Kawamura et al., 1999, 2002; Natsuga
and Kawamura, 2006; Fujita et al., 2010; Li et al., 2011).
Each rough rice sample (about 2 kg) taken after the weighing machine at reception
is automatically carried from one apparatus to the next one through tubes by pneumatic
conveyors, bucket elevators, or by the force of gravity. In this system, rough rice samples
are hulled at first so as not to get stuck in the grain path and also to enable measurement
of percentage of sound whole kernels of brown rice. The rough rice sample is passed
through a huller and a rice cleaner in a room above the inspection room, and the brown
rice sample drops down through the ceiling into the inspection room. A computer (a
local computer) controls all apparatuses and receives information from each apparatus
through serial interface (RS-232C). The local computer is connected to a local area net-
work in the rice grain elevator. Based on the information of quality aspects (protein con-
tent, moisture content, and percentage of sound whole kernel), rough rice transported to
the rice grain elevator can be classified into six qualitative grades: three protein content
levels times two sound whole kernel levels. A host computer of the rice grain elevator
automatically decides which damp holding bin or dryer should be used for the received
rough rice according to the quality information.
Rough rice
Huller
Brown rice
Cleaner
NIR instrument
VIS segregator
Protein content
Moisture content
Sound whole kernel
ratio
FIGURE 14.2
Flowchart of automatic rice quality inspection system.
