A Reappraisal of the Differences Between Scandinavian and Spanish Barleys: Effect of β-Glucan Content and Degradation on Malt Extract Yield in the cv.Scarlett

Abstract

Forty one samples of the malting barley cultivar Scarlett were collected from both Scandinavia (15 from Finland and 10 from Denmark) and the Iberian Peninsula (15 from Spain and 1 from Portugal), during the harvest years of 1998 and 1999. These samples were subjected to grain analyses, comprising protein content, hordein fractions by high performance liquid chromatography (HPLC) and b-glucan content. The samples were micro-malted and the malts were analysed to determine different patterns in the influence of grain composition on malt extract development linked to the two contrasting environments. The most obvious difference found between the Scandinavian and Iberian barleys was the effect of the total and insoluble barley bglucans. They were an effective barrier of malt extract in the North, but appeared to increase extract in the South. A conclusion was that the positive effect of b-glucans in the Iberian barleys was a consequence of their greater capacity to synthesise and release b-glucan hydrolases during germination.Key words: Barley, b-glucans, malting quality. -2863(9'8-32The environmentally induced differences in barley and malt composition observed between samples from such contrasting regions of Northern and Southern Europe as NE Spain and E Scotland, have been analysed for different characteristics and barley genotypes 2,[8][9][10]17,18 . These studies addressed different aspects, but had a common disadvantage in attempting to analyse genotypic differences when the environmental effects were considerably greater 2,9,16 . In an early study by Molina-Cano and coworkers a pair of near-isogenic barley lines were used, and the data for both genotypes showed a positive effect of the B/C hordein ratio and the water-soluble fraction of b-glucans on water uptake during steeping 9 . Additionally, the capacity of the Spanish barleys to give equivalent extracts to their Scottish counterparts, despite higher levels of protein and b-glucans, was attributed to their different hordein composition and their greater ability to produce bglucanases during germination 2 .Subsequent studies focused on comparing environments, using barleys from the North and South of Europe 8 . However, when samples of the variety Alexis grown both in Scandinavia and the Iberian Peninsula were analysed, B-hordeins showed a strong negative effect along with barley protein content on the extract development of the Nordic (Scandinavian) samples 8 . In an attempt to clarify these apparently inconsistent results, we have studied the malting behaviour of the barley variety Scarlett, presently widely accepted by the brewing industry and successfully grown in many European regions. 1%8)6-%07 %2( 1)8,3(7 &EVPI] QEXIVMEPForty one samples of the malting barley variety Scarlett were collected in Scandinavia (25 samples) and the Iberian Peninsula (16 samples) in 1998 and 1999 (Table I). The Scandinavian samples were from Denmark (10 samples) and Finland (15 samples) and those of the Iberian Peninsula were from Spain (14 samples) and Portugal (1 sample)....

Importance of Endosperm Modification for Malt Wort Fermentability1

“…The effect of under modification on fermentability is not well understood even though it is often referred to in the literature 2,11,[13][14][15]22 . Results from the present study suggested several factors were involved in restricting fermentability.…”

Malting Behaviour of Barleys Grown in Canada and Spain as Related to Hordein and Enzyme Content

“…In previous studies on Spanish-vs. Scottish-grown barleys 5,9,17 , South-European vs. North-European grown barleys [11][12][13] and Spanish-vs. Scandinavian-grown barleys [12][13][14] , the Spanish-grown barleys showed a higher capacity to develop degrading enzymes during germination, so circumventing their inherent high-protein drawback. In the present case, whereas BPT exerts a negative influence on Cana- dian FEX and CEX, it did not have a significant influence on these parameters in barley grown in Spain (Table IV).…”

“…Once a good malting variety is identified and its range of geographical adaptation defined, it emerges that the environmental influence (seasons and sites) on its final malting quality is of paramount importance, as shown by recent studies carried out to assess the different patterns of malt extract development in different European regions [11][12][13][14] .…”

“…Two subsequent studies 12,14 focused on a single cultivar in each case, namely Alexis and Scarlett, and the two contrasting regions studied were Scandinavia and the Iberian Peninsula. In these cases the influence of the differential hordein composition in barleys from both regions on malt quality was studied.…”

A study on malt modification, used as a tool to reduce levels of beer hordeins

“…This could again be influenced by the increased breakdown of β ‐glucan during germination, which may increase access for amylolitic enzymes to the endosperm. Also, hydrolysis of β ‐glucan yields glucose which adds to the fermentable sugars and increases fermentability . In conclusion, the overall quality of the worts from all malts was high and extending the period of germination did not negatively affect the results of our tests.…”