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Updated: May 6, 2026
Rapid High Throughput Amylose Determination in Freeze Dried Potato Tuber Samples
Published on: October 14, 2013
Rapid high throughput amylose determination in freeze dried potato tuber samples
Diego Fajardo1, Sastry S Jayanty, Shelley H Jansky
1USDA-ARS and Department of Horticulture, University of Wisconsin - Madison.
Insights
A new colorimetric method uses iodine to quantify starch components, amylose and amylopectin, in potato clones. This inexpensive, high-throughput assay is reliable for evaluating large plant populations.
Area of Science:
- Agricultural Science
- Biochemistry
- Analytical Chemistry
Background:
- Starch composition, specifically the amylose/amylopectin ratio, significantly impacts crop quality and industrial applications.
- Accurate and efficient methods are needed to assess starch profiles in large plant populations, particularly for crop breeding programs.
Purpose of the Study:
- To develop and validate a high-throughput, colorimetric assay for determining the amylose and amylopectin content in starch samples.
- To establish a reliable and cost-effective method for the routine evaluation of starch composition in potato clones.
Main Methods:
- A colorimetric method based on the complex formation between iodine and starch (amylose and amylopectin).
- Spectrophotometric measurement of absorbance at specific wavelengths (620 nm for amylose, 550 nm for amylopectin).
- Quantification using a standard curve derived from known concentrations of starch components.
Main Results:
- The method accurately quantifies amylose and amylopectin based on distinct absorbance maxima.
- The ratio of absorbance at 620 nm to 550 nm correlates with the amylose/amylopectin ratio.
- The protocol demonstrates high throughput, reliability, and reproducibility.
Conclusions:
- This iodine-based colorimetric assay provides an efficient and inexpensive means to determine starch composition.
- The method is suitable for the large-scale evaluation of potato clones, facilitating breeding efforts.
- The protocol offers a valuable tool for researchers and breeders working with starch-rich crops.
Abstract:
This protocol describes a high through put colorimetric method that relies on the formation of a complex between iodine and chains of glucose molecules in starch. Iodine forms complexes with both amylose and long chains within amylopectin. After the addition of iodine to a starch sample, the maximum absorption of amylose and amylopectin occurs at 620 and 550 nm, respectively. The amylose/amylopectin ratio can be estimated from the ratio of the 620 and 550 nm absorbance values and comparing them to a standard curve in which specific known concentrations are plotted against absorption values. This high throughput, inexpensive method is reliable and reproducible, allowing the evaluation of large populations of potato clones.
