Strengthening the Parboiling Process: Reflections Beyond Chapter 4 of Rice Technology
While I discussed the fundamentals of the parboiling process in Chapter 4 of my book Rice Technology, I feel the need to further articulate my perspective—particularly in light of practical challenges and opportunities that still exist in the industry.
Early Work on Parboiling Upgradation (1993–1996)
Between 1993 and 1996, I had the privilege of assisting Dr. K. R. Bhattacharya in upgrading the conventional parboiling system. Over these three years of focused and intensive work, we examined nearly every critical parameter influencing parboiling performance.
Our work primarily involved Basmati rice parboiling, which presented a unique and demanding challenge:
the rice had to retain its superior cooking qualities, especially:
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2.5 times elongation
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Distinct ring formations along the grain length
While hygiene and process cleanliness were important considerations, preserving cooking quality remained the most critical and technically challenging aspect.
Process Optimization Through Controlled Experimentation
We conducted extensive permutations and combinations involving:
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Soaking temperature versus soaking time
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Residence time during steaming
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Steam intensity and exposure duration
Through systematic experimentation and commercial-scale trials, we successfully achieved our objective. The improved process was subsequently adopted by the rice milling fraternity, marking a significant milestone in practical parboiling technology.
However, I must emphasize that the industry has largely stagnated at this point of adoption, without sufficiently exploring further improvements required to meet present and future challenges.
Dry Heat Aging and the Need for Further Innovation
The introduction of Dry Heat Aging was a commendable advancement, primarily aimed at:
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Reducing working capital costs
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Minimizing long-term storage requirements
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Lowering interest burdens on inventory
Yet, while Dry Heat Aging addressed storage and financial concerns, parboiling itself still holds untapped potential, particularly in reducing power consumption.
Pressure-Based Soaking and Steaming: A Breakthrough
To address this, we explored methods to reduce soaking time, experimenting with:
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Vacuum-based soaking
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Pressure-based soaking
Our trials conclusively showed that soaking under pressure was significantly more effective, enabling us to reduce soaking time to just two hours—a result validated through full commercial-scale trials.
Encouraged by this success, I extended the concept to include:
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Soaking under pressure
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Steaming under pressure
The results were astonishing and exceeded expectations. This development challenged some long-held assumptions, including those of my revered Guru, Dr. K. R. Bhattacharya. His gracious acknowledgment and blessings for this achievement remain a deeply cherished memory for me.
The Way Forward: Continuous Parboiling and Energy Integration
The purpose of sharing these insights is not merely retrospective—it is a call to action for the rice milling fraternity.
I strongly believe that the future lies in making the parboiling process continuous, which would allow:
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Effective utilization of back-pressure steam
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Integration with steam turbines for captive power generation
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A drastic reduction in net power costs—potentially to negligible levels
Such integration would significantly enhance millers’ margins, improve energy efficiency, and ensure long-term sustainability in rice processing.