Methods for predicting the malting quality of barley based on assessment of cell wall digestibility
HGCA PROJECT REPORT 218
Methods for predicting the malting quality of barley based on assessment of cell wall digestibility
by
R E Muller
Brewing Research International, Surrey
March 2000
Abstract
Aims
The general aim of this project was to develop procedures for predicting the digestibility of the barley based on the assessment of soluble and insoluble beta-glucan, and the levels of the enzymes involved in beta-glucan solubilisation. In particular we were searching for small-scale analyses that could be used at a very early stage of breeding to enable selection of varieties most suitable for malting and thereby speed up the selection process.
The aim of the first year was to assess the levels of soluble and insoluble beta-glucan in endosperm cell walls in a wide range of barley varieties varying in malting grade and provenance.
In the second year the microstructure of the cell wall in terms of the degree of cross-linking between the cell wall components was investigated.
The final year concentrated on the relationship between the structure of the endosperm cell wall material, the development of hydrolytic enzymes and the rapidity of beta-glucan removal.
Conclusions and Implications
There are three ways in which properties of the cell wall structure may be used as an indication of malting quality:
1. Variation in quality of beta-glucan (good malting barleys are less variable).
2. Cross-linking of the cell wall structure (good malting barleys generally have few cross-linking agents in the endosperm although some non-malting varieties may also be low).
3. Digestion of the cell walls and beta glucan at G2.
Of these the beta-glucan content at day 2 of germination is likely to be the most useful indicator of malting quality.
The test is based on a commercially available test kit but the quantities of material required have been minimised.
Thus the test is ideal for:
Barley breeders
Barley quality assessors
Maltsters
HGCA Project Number: 1188
Price: £5.50
