Table of Contents
The parboiling rice process plays a crucial role in rice production, offering significant benefits such as improved rice yield and reduced grain breakage during milling.
Furthermore, there are four fundamental parboiling methods, each contributing to distinct cooking characteristics and textures. The key difference between these techniques lies in the time-temperature combinations used during the soaking and steaming stages.
With that in mind, let’s take a closer look at each stage in detail.
Types of parboiling rice process
Sella process
● Kachi Tank Pre-Steaming:
Once the paddy is de-stoned and cleaned, the storage bin is fed into the Kachi tank for pre-steaming where the grains steam sufficiently to enable gelatinization upon subsequent heating at 3-bar pressure.
This pre-steaming process reduces the soaking time of the paddy and increases the capacity of the rice to absorb water during cooking.
● Soaking:
The steamed paddy is then soaked in water for moisture saturation and generalization.
● Pakki Steaming System:
The soaked paddy is drained and then transferred to a final steaming at 3-bar pressure.
● Tapered V Dryer:
The paddy is dried using a specialized drying mechanism to evaporate moisture content from approximately 36% to 12%.
● Transported to Rice Mill:
The processed paddy is then cooled down to room temperature and transported to the rice milling area for final rice production.
Boiled Rice Process
● Soaking:
In this process, the cleaned paddy is first soaked and circulated in hot water at 70 degrees Celsius.
● Online Cooker:
The soaked paddy is mechanically elevated by an automated conveyor system and fed into an online cooker, where it undergoes high-pressure steaming at 3 bars to enhance gelatinization.
● Tapered V Dryer:
The paddy is dried using a specialized drying mechanism to evaporate moisture content from approximately 36% to 12%.
● Transported to Rice mill:
The processed paddy is then cooled down to room temperature and transported to the rice milling area for final rice production.
Half-boiled Rice Process
● Soaking:
In half-boiled rice process, the cleaned paddy is soaked and circulated in cold water at ambient temperatures to increase the moisture content and enhance the gelatinization process.
● Online Cooker:
The paddy is mechanically elevated by an automated conveyor system and fed into an online cooker, where the soaked paddy undergoes continuous steaming at 0.8 – 2 bar pressure.
● Tapered V Dryer:
The paddy is dried using a specialized drying mechanism to evaporate moisture content from approximately 36% to 12%.
● Transported to Rice mill:
The processed paddy is then cooled down to room temperature and transported to the rice milling area for final rice production.
Steamed Rice Process
● First-pass Drying:
In this process, the paddy is directly fed into the dryer system, where the moisture content is brought down to 18%-20%.
● Online Cooker:
The dried paddy is fed into an online cooker for final steaming at 0.8 – 1.5 bar pressure.
● Second-pass Drying:
The steamed paddy is again dried to reduce the moisture content from 32% to 12%.
● Transported to Rice mill::
The processed paddy is then cooled down to room temperature and transported to the rice milling area for final rice production.
Conclusion
Each of these parboiling techniques follows a unique combination of soaking, steaming, and drying. Carefully monitoring temperature and pressure at each stage will ensure better texture, nutritional retention, and market value.
FAQ
Q1: What is the main purpose of parboiling process?
A: To reduce grain breakage and increase the total rice yield during milling operation.
Q2: Can all types of rice be processed in a paddy parboiling plant?
A: Yes, but the machinery might be adjusted or specialized for different rice varieties.
Q3: What happens to the by-products of rice processing?
A: Husks can be used for energy, bran for oil, and broken rice for animal feed or brewing.
Q4: Is there an environmental impact from paddy processing plant operations?
A: There can be; proper waste management and energy-efficient machinery reduce this impact.
