The Effect of Nitrogen Level on the Performance of Malting Barley Varieties during Germination

Abstract

The malting characteristics of high and low nitrogen barleys were compared. Results confirmed that low nitrogen facilitates malting rate and extract development. Modification rate was not related to (3-glucan content. In general, these low nitrogen barleys and high nitrogen barleys had similar levels of a-amylase but high nitrogen barleys tend to have higher levels of fi-amylase.Since barleys of similar nitrogens had different levels of a-amylase and p-amylase, nitrogen may not be a reliable indicator of the potential of the grain to develop amylolytic enzymes.

Malting Performance of Normal Huskless and Acid-Dehusked Barley Samples

“…The lower level of amylolytic enzymes developed in the barley samples, which contained small percentages of ungerminated grains, resulted in lower levels of b-amylase when the grain was malted. As reported previously 6,15,23 , b-amylase development is more correlated with malt modification than with nitrogen levels alone. The higher FAN products in the wort of the higher nitrogen (normal huskless) barley suggest that there is a good correlation between barley nitrogen and a-amino nitrogen production.…”

“…When malted for 5 days, and mashed in a similar way, the normal huskless barley produced 30% more FAN products in the wort than the aciddehusked barley (Table IV). Such differences in soluble nitrogen production were not correlated with differences in the development of amylolytic activity 6 .…”

“…It is important to note that both types of barley malts developed high extract yield on day 5 germination. The higher extract yield of the malt of aciddehusked Halcyon barley over the same period of germination could have resulted from a difference in the total nitrogen content as well as varietal difference of both samples 6 (Table I). The higher residual b-glucan in the malt of the normal huskless barley reported in Table II is further reflected in both the higher wort viscosity and wort b-glucan shown in Table IV.…”

“…This may be because barley with a lower total nitrogen content may achieve a more uniform and greater degree of modification than barley which is higher in total nitrogen. This results in higher soluble nitrogen ratios 6,25,28 . With regard to the work reported here, another interesting observation was found in the relationship between total nitrogen content of barley and level of FAN products of the malt.…”

Pattern of Nitrogen Distribution in Barley Grains Grown in the Field

“…One of the most important parameters is the nitrogen content of the grains of malting barley 1,2 . Grain size distribution is another important factor because grains of different sizes will absorb differing amounts of water during steeping and hence modify at different rates during malting.…”