Near infrared hyperspectral imaging of blends of conventional and waxy hard wheats

Jianwei Qin,Moon Kim,Robert Graybosch,Stephen Delwiche,Steven Rausch

doi:10.1255/jsi.2018.a2

Abstract

Recent development of hard winter waxy (amylose-free) wheat adapted to the North American climate has prompted the quest to find a rapid method that will determine mixture levels of conventional wheat in lots of identity preserved waxy wheat. Previous work documented the use of conventional near infrared (NIR) reflectance spectroscopy to determine the mixture level of conventional wheat in waxy wheat, with an examined range, through binary sample mixture preparation, of 0–100% (weight conventional / weight total). The current study examines the ability of NIR hyperspectral imaging of intact kernels to determine mixture levels. Twenty-nine mixtures (0, 1, 2, 3, 4, 5, 10, 15, …, 95, 96, 97, 98, 99, 100%) were formed from known genotypes of waxy and conventional wheat. Two-class partial least squares discriminant analysis (PLSDA) and statistical pattern recognition classifier models were developed for identifying each kernel in the images as conventional or waxy. Along with these approaches, conventional PLS1 regression modelling was performed on means of kernel spectra within each mixture test sample. Results indicated close agreement between all three approaches, with standard errors of prediction for the better preprocess transformations (PLSDA models) or better classifiers (pattern recognition models) of approximately 9 percentage units. Although such error rates were slightly greater than ones previously published using non-imaging NIR analysis of bulk whole kernel wheat and wheat meal, the HSI technique offers an advantage of its potential use in sorting operations.

Highlights

Waxy starches in cereal grains arise from the near complete absence of the linear chain [a-(1→4)-linked glucan units] macromolecule amylose, causing the starch to be composed exclusively of the branched [a -(1→6)-linkages] chain macromolecule amylopectin
The parent samples, with each in its own canvas bag, were placed in a 50 L polyethylene sealed container for a one-month moisture equilibration period, whereupon mixture laboratory samples for each pair were prepared by weighing out precisely defined portions to the nearest kernel
The authors’ earlier study using diffuse reflectance spectroscopy (1100–2500 nm) of ground meal demonstrated the advantage of spectral preprocessing to reduce physical effects, especially with respect to the wavelength region beyond 2000 nm.[15]

Summary

Introduction

Waxy starches in cereal grains arise from the near complete absence of the linear chain [a-(1→4)-linked glucan units] macromolecule amylose, causing the starch to be composed exclusively of the branched [a -(1→6)-linkages] chain macromolecule amylopectin. In hexaploid wheat (Triticum aestivum L.), the waxy condition arises from the simultaneous presence of null mutations at each of the three genetic loci (Wx-A1, Wx-B1 and Wx-D1) that. This licence permits you to use, share, copy and redistribute the paper in any medium or any format provided that a full citation to the original paper in this journal is given. Hyperspectral Imaging of Waxy Wheat encode for the enzyme granule bound starch synthase (GBSS) which controls amylose synthesis. Such wheats may offer unique uses for shelf life extension, ethanol production and non-food applications.[4,5,6]

Methods

Results

Conclusion