Development of a Single Kernel NIR Barley Protein Calibration and Assessment of Variation in Protein on Grain Quality

Abstract

In this paper, we describe results from a preliminary experiment on the development of a near infrared reflectance (NIR) calibration for single kernel (SK) % protein content in barley. The SKNIR calibration was developed using kernels from breeding lines and commercial barley varieties with a range in protein content of 7.3% to 16.6% "as is" . The calibration model produced an R 2 = 0.903, while the validation set had a R 2 = 0.837 with a standard error of cross validation and a standard error of prediction of 0.8% for both the calibration and validation sets respectively. The calibration was then used to estimate the variation in % protein of 4,000 single kernels from a commercial variety (Gairdner at 9.3% protein) by segregating kernels into six sub-groups (<7.8%, 7.9-8.3%, 8.4-9.0%, 9.1-9.7%, 9.8-10.4%, >10.5% "as is" ). These sub-groups then had additional grain quality tests carried out including grain size, thousand kernel weight and NIR estimates of % protein, starch, hardness and barley hot water extract (HWE). The results showed an increase in grain size, and a decrease in HWE from the low to high % protein sub-groups. While only a single variety was used in the SKNIR protein segregation study, the results suggested SKNIR could be used to screen for the variation in grain quality traits based on variation in protein content.

Infrared spectral analysis of sugar profiles of worts from varying grist to liquor ratios using infusion and ramping mash styles

“…The production of wort and its subsequent analysis is time consuming so less expensive and rapid predictive methods have been utilized. Near‐infrared spectroscopy has been used for decades to predict barley malt traits associated with improved quality including in single grains of barley and starch, proteins and lipids in barley grain, malt and wort . Near‐infrared spectroscopy has been used to predict malt and wort quality and beer quality but its use in breeding programmes is where is has the greatest value .…”

The Brewing Industry and the Opportunities for Real-Time Quality Analysis Using Infrared Spectroscopy

“…Typical analysis of barley protein content is on bulk samples with 1000 s of grains in the sample tested. However, several studies have shown NIR has the capacity to scan and predict single grains and from that data show the distribution of protein content in a sample [21][22][23]. These studies showed variation between single kernels within a spike of barley as well as variation in other quality parameters based on grains sorted into sub-groups of protein content.…”

Applications of single kernel conventional and hyperspectral imaging near infrared spectroscopy in cereals

“…SK‐NIR calibrations for protein content in wheats have shown similar levels of accuracy in other grains, including maize protein content and amino acid content in maize . In barley, protein content of individual kernels varied within a spike . In addition, one study reported sorting 4000 barley kernels into five protein sub‐samples; those sub‐samples (20–30 g) were then used to predicted other barley traits using conventional bulk NIR calibrations …”

“…24 In barley, protein content of individual kernels varied within a spike. 25,26 In addition, one study reported sorting 4000 barley kernels into five protein sub-samples; those sub-samples (20-30 g) were then used to predicted other barley traits using conventional bulk NIR calibrations. 25 One of the key aspects in developing NIR calibrations are the reference methods.…”