Rice Core Heat-Cool Processing for Low-Glycemic Rice
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Solution Overview
Problem
Existing rice products, particularly white rice, have a high glycaemic index, which is associated with a higher risk of type 2 diabetes, and there is a need for a reliable and repeatable method to produce rice with a low glycaemic index and load.
Innovation Solution
A method involving humidification, controlled heating and cooling of husked brown rice using microwave or radiofrequency energy to create resistant starch RS3, which reduces the glycaemic index and load, while maintaining the natural flavor and aroma, by gelatinising only the rice core and promoting retrogradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If white rice is consumed, then it provides energy, but it has a high glycaemic index which increases diabetes risk
Solution Approach 1:
The patent applies parameter changes by controlling moisture content (18-22%), temperature (85-95°C), and time (3-5 minutes) during heating and cooling processes to transform starch structure. This creates resistant starch that lowers the glycaemic index from typical white rice levels (65-94) to below 40, reducing diabetes risk while maintaining energy provision
Solution Approach 2:
The patent creates a composite starch structure within the rice grain, combining gelatinized starch (from heated core) with retrograded resistant starch (formed during cooling). This composite structure maintains the rice's nutritional value and energy provision while significantly reducing the glycaemic response
2Object-affected harmful factors
If parboiled rice is used, then carbohydrate content is reduced and nutrients are preserved, but consistency becomes hard and tough making it unappealing
Solution Approach 1:
The patent applies local quality by heating only the core of the rice grain to gelatinize the starch, while the outer layers remain relatively unaffected. This localized treatment creates resistant starch in the core without overcooking the entire grain, maintaining appealing consistency while reducing carbohydrate availability
Solution Approach 2:
The patent uses periodic action through alternating heating and cooling cycles. The rice is heated to gelatinize starch, then rapidly cooled to promote retrogradation. This periodic thermal treatment creates resistant starch while preserving the rice's desirable texture and consistency
3Ease of operation
If heating is applied to gelatinise starch, then digestibility increases, but glycaemic index increases
Solution Approach 1:
The patent applies preliminary action by heating the rice to gelatinize starch before consumption, which improves digestibility. However, it immediately follows with rapid cooling to promote retrogradation, creating resistant starch that reduces glycaemic impact. This preliminary heating-cooling sequence modifies starch structure to achieve both goals
4Manufacturing precision
If moisture content is increased for processing, then gelatinisation is improved, but product quality may deteriorate
Solution Approach 1:
The patent precisely controls moisture content at 18-22% during processing, which is sufficient to enable starch gelatinisation in the grain core during heating but low enough to prevent excessive softening or deterioration of product quality. This optimized moisture parameter achieves both gelatinisation and quality preservation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively lowers the glycaemic index and load of rice to below 40, making it suitable for diabetic consumption, while enhancing gut health through resistant starch RS3 formation.
Implementation Method 1
The two heating steps are carried out in MW or RF apparatus, preferably for about 3 minutes. MW (microwave) means frequencies comprised between 300 MHz and 300 GHz
Implementation Method 2
RF (radiofrequency) means frequencies of less than 300 MHz and in particular use is made of frequencies of 27.12 MHz in Italy and the EU
Implementation Method 3
When gelatinised starch cools, it tends to return to a configuration similar to the initial one and this phenomenon is called 'starch retrogradation'. Resistant starch RS3 is retrograded.
Implementation Method 4
Initially, the rice is humidified until reaching a moisture content equal to 18-22%
Data Source
AI summary
A method for producing rice with a low glycemic index and a low glycemic load includes, in sequence, preparing husked brown rice, humidifying the rice with water at room temperature until reaching a moisture content equal to 18-22%, resting the rice for 24-60 minutes, heating the rice to a temperature of 80-85° C., cooling the rice in an environment at a temperature lower than the room temperature until the rice reaches a temperature of 10° C., reconstituting the rice for 24-72 hours, maintaining the moisture content, until the rice reaches the room temperature, heating the rice again until the rice externally reaches a temperature of 60-65° C., corresponding to an internal temperature greater than 70° C., cooling the rice to reach the room temperature, refining the rice having a moisture content equal to 18-22% and drying until reaching a moisture content equal to 12-13%.