Rice Resistant Starch Preparation via Multi-Enzyme Modification
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Solution Overview
Problem
Rice starch is easily digested and absorbed, leading to high postprandial blood glucose levels, and existing methods for increasing resistant starch content, such as using pullulanase, result in limited formation of short linear chains and lower resistant starch levels due to insufficient chain length and crystallization.
Innovation Solution
A green preparation method using β-amylase, glucoside transferase, and pullulanase below the gelatinization temperature to modify rice starch, producing short linear chains that can effectively recrystallize at 4°C, forming high-resistant starch content without disrupting the inherent crystal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pullulanase is used to modify starch, then the starch is debranched and transformed into shorter linear glucan, but the chain length ranges from 6 to 60 resulting in limited formation of short linear chains with double helix crystals and lower resistant starch level
Solution Approach 1:
The patent segments the enzyme modification process into three distinct stages using different enzymes: β-amylase for initial hydrolysis, glucoside transferase for chain transfer and shortening, and pullulanase for final debranching. This segmentation allows each enzyme to perform its optimal function, producing a concentrated range of short linear chains (DP 6-15) that efficiently form resistant starch crystals.
Solution Approach 2:
The patent changes the chain length parameter distribution by using a multi-enzyme system that specifically generates short linear chains with degree of polymerization 6-15. This parameter optimization enables more efficient formation of double helix crystals compared to the broader chain length distribution (6-60) produced by pullulanase alone, thereby increasing resistant starch content.
2Manufacturing precision
If starch is treated above gelatinization temperature, then the starch granules collapse completely and crystalline area disappears, but this is not conducive to the formation of resistant starch and increases energy consumption
Solution Approach 1:
The patent applies preliminary enzymatic modification to the starch at or below gelatinization temperature before any heat treatment. The multi-enzyme system pre-forms short linear chains and modifies the starch structure in advance, so that subsequent cooling can directly induce resistant starch crystallization without requiring high-temperature gelatinization, thus saving energy and preserving crystalline structure.
Solution Approach 2:
The patent changes the temperature parameter from above gelatinization temperature to at or below gelatinization temperature during enzymatic modification. This parameter change prevents complete collapse of starch granules and disappearance of crystalline areas, maintaining the structural foundation necessary for resistant starch formation while reducing energy consumption.
3Productivity
If gelatinization is applied to rice starch, then the starch granules collapse completely, but the inherent crystal structure inside the starch granules is disrupted which is not conducive to resistant starch formation
Solution Approach 1:
The patent performs preliminary enzymatic chain modification and shortening before any gelatinization or heat treatment. By pre-forming the appropriate chain length distribution and structure at lower temperatures, the starch is prepared in advance to facilitate resistant starch crystallization upon cooling, eliminating the need for high-temperature gelatinization that would destroy the crystal structure.
Solution Approach 2:
The patent inverts the conventional processing sequence by performing enzymatic modification and chain shortening before gelatinization rather than after. This reversal allows the starch to maintain its crystalline structure during modification, and the modified chains can then spontaneously recrystallize into resistant starch form upon cooling, preserving structural integrity throughout the process.
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 significantly increases resistant starch content and improves digestibility, reducing energy consumption and maintaining the inherent crystal structure, resulting in a product with enhanced nutritional benefits and industrial feasibility.
Implementation Method 1
BA hydrolyzes the α-(1→4) glycosidic bond in the rice starch from the non-reducing end of the chain
Implementation Method 2
TG further catalyzes β-glucan through hydrolysis and transfer reactions to produce more β, T-glucans with short branched α-(1→6) glycosidic bonds
Implementation Method 3
PUL cleaves the α-(1→6) glycosidic bond of β, T-glucan and produces a greater amount of short linear chains of appropriate length
Implementation Method 4
resulting in a number of short linear chains which are effectively arranged, aggregated, and recrystallized at 4° C. to form modified rice starch with high resistant starch content
Data Source
AI summary
Green preparation methods of rice resistant starch are disclosed. In some embodiments, a green preparation method of the rice resistant starch is characterized in that, at a temperature lower than the gelatinization temperature, the rice starch is sequentially modified by enzymes using β-amylase, glucosidase, and pullulanase to obtain the modified starch. In other embodiments, a green preparation method of the rice resistant starch is characterized by using: rice starch as a substrate; and in turn using: (a) β-amylase (BA, EC 3.2.1.2) from barley (Hordeum vulgare); (b) glucoside transferase (TG, EC 2.4.1.24) from Aspergillus niger; and (c) pullulanase (PUL, EC 3.2.1.41) from Pullulanibacillus konaensis below a gelatinization temperature to modify a chain structure of the rice starch, resulting in a number of short linear chains which are effectively arranged, aggregated, and recrystallized at 4° C. to form modified rice starch with high resistant starch content.