Abstract
Starchy foods are a major staple in human nutrition, with rice alone regularly consumed by more than half of the global population. Starch is a branched glucose homopolymer that when ingested undergoes a complex series of physical and biochemical digestion processes to breakdown the polymer to generate glucose. Starch is prevalent in many configurations which can influence the release of its sugars. The digestibility of starch has important implications for an individual’s health such as maintaining blood glucose levels to reduce the risk of type 2 diabetes. Understanding starch digestion is an important field of study for the development of foods with desired digestibility characteristics.
Several methods exist to monitor glucose release. The glucometer, for example, is a quick and easy method that can be directly used to analyse blood glucose. While suitable for monitoring glucose in blood, its narrow working range is not suitable to more complex applications. Other methods for detecting and quantifying sugars such as high-performance liquid chromatography (HPLC) are effective, however, require tedious sample preparation. There is an opportunity to develop a highly discriminative, robust method capable of accurate and precise identification and quantification of sugar molecules.
Capillary electrophoresis (CE) has increasingly garnered wide interest for the application to food analysis largely due to its cost-effectiveness while retaining a high level of molecular separation and efficiency. CE has been demonstrated to be highly robust and requiring little to no sample preparation. These characteristics make CE an ideal instrument for the separation and quantification of sugar molecules released from starch digestion.
This study evaluated the ability of CE to monitor sugar release during in vitro digestion reactions of rice starch. CE was first shown to separate and quantify rice starch metabolites: glucose but also maltose and maltotriose. Resolution between maltose and maltotriose was obtained with valley-to-peak ratio ≤5% at 2 g.L-1. The throughput was increased using continuous sequential injection (CSI). The enhanced throughput method was used to analyse increasingly more complex samples including rice starch standards and rice grains.
Implementing sequential continuous injections increased overall throughput by a factor of four. Sugars can be identified with ≤1% RSD on corrected electrophoretic mobility and can be quantified with ~10% RSD on peak area and concentration. The CE method when compared against GO-POD was considered reproducible on same samples. Analysis data generated from CE was able to be used to distinguish between rice varieties with different digestibility properties when monitored online and offline.
This type of method may find application in industrial and research settings which stand to benefit from better understanding starch digestion.
The method could be complementary to in vivo digestibility monitoring protocols as a lower cost alternative to screen the digestibility of starchy foods. Also, the technique could be useful for other applications where accurate separation and quantification of sugar molecules is required.
Several methods exist to monitor glucose release. The glucometer, for example, is a quick and easy method that can be directly used to analyse blood glucose. While suitable for monitoring glucose in blood, its narrow working range is not suitable to more complex applications. Other methods for detecting and quantifying sugars such as high-performance liquid chromatography (HPLC) are effective, however, require tedious sample preparation. There is an opportunity to develop a highly discriminative, robust method capable of accurate and precise identification and quantification of sugar molecules.
Capillary electrophoresis (CE) has increasingly garnered wide interest for the application to food analysis largely due to its cost-effectiveness while retaining a high level of molecular separation and efficiency. CE has been demonstrated to be highly robust and requiring little to no sample preparation. These characteristics make CE an ideal instrument for the separation and quantification of sugar molecules released from starch digestion.
This study evaluated the ability of CE to monitor sugar release during in vitro digestion reactions of rice starch. CE was first shown to separate and quantify rice starch metabolites: glucose but also maltose and maltotriose. Resolution between maltose and maltotriose was obtained with valley-to-peak ratio ≤5% at 2 g.L-1. The throughput was increased using continuous sequential injection (CSI). The enhanced throughput method was used to analyse increasingly more complex samples including rice starch standards and rice grains.
Implementing sequential continuous injections increased overall throughput by a factor of four. Sugars can be identified with ≤1% RSD on corrected electrophoretic mobility and can be quantified with ~10% RSD on peak area and concentration. The CE method when compared against GO-POD was considered reproducible on same samples. Analysis data generated from CE was able to be used to distinguish between rice varieties with different digestibility properties when monitored online and offline.
This type of method may find application in industrial and research settings which stand to benefit from better understanding starch digestion.
The method could be complementary to in vivo digestibility monitoring protocols as a lower cost alternative to screen the digestibility of starchy foods. Also, the technique could be useful for other applications where accurate separation and quantification of sugar molecules is required.
Original language | English |
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Qualification | Doctor of Philosophy |
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Place of Publication | Australia |
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Publication status | Published - 2023 |