Introduction
People’s demands for rice quality and nutritional value are increasing. Both white rice and parboiled rice are popular in the market, each with its advantages and benefits. Choosing the right rice processing method for rice mills can help you secure a place in the market. I will compare the two in this article to help you make the right choice.
The Difference between Parboiled Rice and White Rice
Definition
White Rice
White rice is the product obtained after multiple refining steps on paddy. These steps include removing the outer husk, bran layer, and germ, leaving behind mostly the starchy endosperm.
Parboiled Rice
Parboiled rice is made from paddy that undergoes a series of hydrothermal processes while still retaining the husk. The process includes soaking, steaming, drying, and cooling. After these steps, the husk is removed, and the rice is milled to produce the final product.
Processing Steps
White Rice
Pre-cleaning
Before processing, the paddy needs to be cleaned using a grain cleaner and a vibrating screening machine. During harvesting and threshing, impurities like broken straw, soil, and stones can mix in. If you do not remove these impurities, they can damage the rice processing machines.
Rice dehusking
Cleaned paddy can be processed using a husker machine to remove the husk. The key part of the husker machine, the rubber rollers, separates the husk from the rice through friction. The result is known as brown rice.
Paddy separating
During the husking process, some paddy may not be fully husked. In this case, you need a paddy separator screen. This machine uses differences in weight, size, and friction between paddy and brown rice to gradually sort the mixture. Brown rice, which is heavier and smaller, sinks, while paddy, which is lighter and larger, floats to the top. The separator then allows the brown rice to flow out from the top and the paddy to flow out from the bottom.
Whitening
To make the rice look more attractive and marketable, brown rice needs to be polished using a rice whitener. In the rice whitener, the abrasive rollers remove the outer layer of the brown rice, taking off the light brown skin and germ, and turning it into white rice.
Grading
During rice processing, broken rice is produced. To sell it at a higher price, you need to grade it. A rod-type rotary grader solves this problem by using a clockwise motion to separate broken rice and whole rice as they pass through screens with different-sized holes in the grader.
Color Sorting
To improve the quality of the rice, you can use a color sorter to screen the processed rice. This machine removes discolored grains, moldy rice, and grains with spots, helping to increase the purity and overall quality of the rice.
Polishing
If you want to sell rice to customers who have higher quality demands, you can use a polishing machine. This machine makes the rice shinier and helps it stay fresh for a longer time.
Parboiled Rice
Compared to white rice, parboiled rice requires several additional parboiled rice machines before processing.
Soaking
First, place the cleaned paddy into a soaking tank with water heated to 80-90°C. Soak it for three hours to allow the paddy to absorb enough moisture. The water temperature should be maintained at 70°C during soaking, and the paddy should have a moisture content of over 40% after soaking to prepare for starch gelatinization.
Steaming
Place the soaked paddy into a machine with a steam distributor. High-temperature steaming helps to gelatinize the starch in the paddy, changing its physical structure and allowing the nutrients to be better retained in the rice grains.
Drying
After steaming, workers drain the paddy from the tank and transport it by a belt conveyor or bucket elevator to a fluidized bed for quick drying. They then move it into a drying tower, where it cycles to reduce the moisture content to 14%, preparing it for the next processing steps.
Appearance and Flavor
White Rice
White rice usually appears bright white because the milling process removes the bran and the outer layer, making the rice grains cleaner and giving them a higher shine.
Rice made from white rice is soft and delicate, easy to digest, and has a mild, slightly sweet taste that suits most people’s preferences.
Parboiled Rice
Parboiled rice has a natural, sparkling appearance with a golden amber color. This is due to its unique processing method, where the husk and germ are not removed during the hydrothermal process, giving the rice its distinctive color.
Rice made from parboiling has a better texture, with a chewier bite and a more robust, natural grain flavor. It has a richer taste compared to white rice.
Cooking
White Rice
Cooking white rice takes longer, usually about 20 minutes.
Parboiled Rice
The steaming process during processing makes parboiled rice cook faster, usually in about ten minutes. Additionally, when cooking the rice, you need to use a bit more water compared to cooking white rice.
Shelf Life and Storage
White Rice
During processing, the mill removes the outer layers of white rice, including the germ and bran, which lowers the fat content to just 0.2% per 100 grams of rice. This makes it less likely to go rancid. However, the environment, especially humidity and temperature, can affect white rice during storage. If not stored properly or for too long, it can spoil or develop insects. Therefore, it should be kept in a dry, cool place.
Parboiled Rice
Steaming parboiled rice stabilizes its internal structure, kills most microbes, and reduces insect damage. They also dry it, which lowers its moisture content. As a result, it has a longer shelf life compared to white rice. Because of these qualities, it doesn’t require strict storage conditions and can withstand various climate conditions.
Health Benefits
White Rice
Since white rice has had its bran and germ removed, it is easier to digest. It also raises blood sugar quickly, providing energy after physical activity. Additionally, white rice has a low fiber content, making it suitable for people who need a low-fiber diet.
Parboiled Rice
During the steaming process, water and heat cause natural vitamins, minerals, and dietary fiber from the husk and bran of the paddy to move into the endosperm. This helps retain the nutrients from the husk, germ, and endosperm. Additionally, it has a low glycemic index, which helps stabilize blood sugar levels.
Market Appeal and Use Cases
White Rice
White rice processing technology is well-established and cost-effective. In countries where rice is a staple food, such as China, Japan, South Korea, and India, people often prefer traditional white rice for its appearance and taste.
Parboiled Rice
As living standards improve, people are looking for healthier food options. Parboiled rice, with its high nutritional value and low glycemic index, is becoming more popular among consumers. As health awareness continues to grow in the future, people are expected to increase their consumption of parboiled rice, leading it to gain a larger market share and become an important part of daily diets.
Wrap Up
As I mentioned earlier, both white rice and parboiled rice have their advantages. Whether you choose to process traditional white rice or modern parboiled rice depends on your target market and consumer needs. Whatever you choose, ANON offers the right equipment for both. Feel free to reach out for more information!
FAQ
Can diabetics eat parboiled rice?
During processing, parboiled rice has an optimized starch structure, a lower glycemic index, and slower sugar absorption, making it a suitable staple food for diabetics. Additionally, parboiled rice provides a stronger feeling of fullness, helping diabetics manage hunger during dietary control.
