There are two industrial microwave applications for rice mills: Rice weevils disinfestations and rice bran stabilization.

The Problems Statement of Rice Weevils

Weight Lost:

It is estimated that annual losses of cereal grains due to insects and rodents are approximately 10% in North America and up to 50% in Africa and Asia

Reduced quality of rice：

These pests/insects not only reduce the product quality by direct damage through feeding and indirectly by producing webbing and frass.

Food safety issues：The traditional treatment is chemical fumigation due to low cost, fast speed in processing and ease of use. However, there are some disadvantages of chemical fumigation.

–Consumer health hazards

–Methyl bromide (Ozone layer depletion)

–Aluminium phosphide (Increasing pest resistance)

–Methyl bromide will be global phase-out

–Under Montreal Protocol by 2015.

The idea of using microwave energy for controlling insects was used in insect control. There are some advantages of industrial microwave insect disinfection.

One of the most important advantages of using industrial microwave heating is that rice or other grain absorb microwave energy directly and internally and convert it into heat and adopt the idea of killing insects by microwave on the dielectric heating effect produced in grain which is a relatively poor conductor of electricity.

Completely mortality of adult Weevil and Larvae

Very low processing cost 

Rapid and uniform heating (disinfection time less than 3 min)

Microwave conveyor process allows large throughput

Safe and competitive alternative method to chemical fumigation

Food safety and non-environmental pollution

Instant on/off operation; no thermal inertia

Saves installation foot-print

Automatic control of temperature/power

24 hours non-stop operations

Improve the sensory quality of cooked rice

Free Fatty Acid increases less in microwave-treated than in non-treated rice

Microwave treatment may reduce lipase activity

Rice keeps a better freshness after microwave treatment

Rice bran stabilization

Primary reason of underutilized of rice bran is due to the rapid onset of hydrolytic rancidity. Unextracted oil will be hydrolyzed into free fatty acid (FFA) by active lipase enzymes rapidly (about 5-7% per day, up to 70% in a month). FFA > 10% is unfit for human consumption; due to high refining loss, make it unprofitable. Immediate rice bran stabilization by microwave heating (100-110oC) to deactivate lipase enzymes and to suppress growth of FFA, is therefore potential for commercialization. Microwave stabilized rice bran can be stable for up to one month in storage. Growth of FFA stabilized by microwave treated lower than control samples throughout storage. Microwave treatment may suppress lipase activity. Microwave treated rice bran keeps three weeks without off-odour.