A New Germinative Classification Model of Barley for Prediction of Malt Quality Amplified by a Near Infrared Transmission Spectroscopy Calibration for Vigour “On Line” Both Implemented by Multivariate Data Analysis
Lars Munck 1 and Birthe Møller
1Corresponding author. E-mail: lmu@kvl.dk, bm@kvl.dk
Web page: www.models.kvl.dk
J. Inst. Brew. 110(1), 3–17, 2004 | VIEW ARTICLE
ABSTRACT
A new germinative two-dimensional classification plot fully
compatible to the current EBC analyses (EBC methods 3.5–3.7)
is proposed for malting barley based on separate estimates
for “vigour” (24 h germination) as abscissa with limits at
70% and 30% and for “viability” (72 h germination) as ordinate
with limits at 98% and 92%. Early detection of germination
by image analysis was improved by utilising the auto fluorescence
of the root cap. The seven hierarchical germinative classes
visualise the quality differences in a consistent way, ordering
classes according to falling extract % and increasing wort
β -glucan (mg/L).
It was surprising to discover that significant barley Near Infrared Transmission (NIT) spectroscopy based Partial Least Squares Regression prediction models for “vigour” and “viability” were obtained after removing the PLSR outliers. The majority of these were found to be low in vigour.
It was concluded after experimental validation that the physical- chemical structure of the seed, reflected by the correlation of the barley NIT spectral fingerprints to germination speed, is connected to the availability of substrate for germ growth. This is another aspect of the speed of malt modification.
An automated combination instrument for measuring physicalchemical and seed germination parameters is suggested for quality control and to establish an on-line NIT calibration network for integrated germinative and malting quality classification.
Key words:
Germinative classification, malting barley, seed vigour,
seed viability, malt quality, near infrared transmission spectroscopy.
Publication no. G-2004-0317-204 ©2004 The Institute & Guild of Brewing