Predicting moisture content during maize nixtamalization using machine learning with NIR spectroscopy

Michael J. Burns, Jonathan S. Renk, David P. Eickholt, Amanda M. Gilbert, Travis J. Hattery, Mark Holmes, Nickolas Anderson, Amanda J. Waters, Sathya Kalambur, Sherry A. Flint-Garcia, Marna D. Yandeau-Nelson, George A. Annor, Candice N. Hirsch

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


KEY MESSAGE: Moisture content during nixtamalization can be accurately predicted from NIR spectroscopy when coupled with a support vector machine (SVM) model, is strongly modulated by the environment, and has a complex genetic architecture. Lack of high-throughput phenotyping systems for determining moisture content during the maize nixtamalization cooking process has led to difficulty in breeding for this trait. This study provides a high-throughput, quantitative measure of kernel moisture content during nixtamalization based on NIR scanning of uncooked maize kernels. Machine learning was utilized to develop models based on the combination of NIR spectra and moisture content determined from a scaled-down benchtop cook method. A linear support vector machine (SVM) model with a Spearman's rank correlation coefficient of 0.852 between wet laboratory and predicted values was developed from 100 diverse temperate genotypes grown in replicate across two environments. This model was applied to NIR spectra data from 501 diverse temperate genotypes grown in replicate in five environments. Analysis of variance revealed environment explained the highest percent of the variation (51.5%), followed by genotype (15.6%) and genotype-by-environment interaction (11.2%). A genome-wide association study identified 26 significant loci across five environments that explained between 5.04% and 16.01% (average = 10.41%). However, genome-wide markers explained 10.54% to 45.99% (average = 31.68%) of the variation, indicating the genetic architecture of this trait is likely complex and controlled by many loci of small effect. This study provides a high-throughput method to evaluate moisture content during nixtamalization that is feasible at the scale of a breeding program and provides important information about the factors contributing to variation of this trait for breeders and food companies to make future strategies to improve this important processing trait.

Original languageEnglish (US)
Pages (from-to)3743-3757
Number of pages15
JournalTheoretical and Applied Genetics
Issue number11
Early online dateAug 3 2021
StatePublished - Nov 2021

Bibliographical note

Funding Information:
This work was funded in part by NSF IOS-1546272 to CNH and MDY-N, PepsiCo, Inc. to CNH, the Iowa Agriculture and Home Economics Research Station Project IOW03649 to MDY-N, and USDA-ARS base funds to SF-G.

Funding Information:
The authors acknowledge the Minnesota Supercomputing Institute (MSI) at the University of Minnesota for providing resources that contributed to the research results reported in this paper.

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.


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