Rapid Spectrophotometric Measurement of Soluble Nitrogen in Micromalts From a Barley Breeding Programme

Abstract

A spectrophotometric method for determining soluble protein has been applied to the measurement of soluble nitrogen (SN) in micromalts from a barley breeding programme. A regression equation between wort SN values, measured by the KJeldahl method, and the absorbance difference (A21B-A22B|) of diluted wort samples was prepared and then used to predict SN levels of 353 worts produced from breeding material from a diverse genetic background. These data were highly correlated with those obtained from the Kjeldahl method (r = 0.952***). A second calibration equation relating wort absorbance at a single wavelength (A21B) to Kjeldahl nitrogen data was able to predict wort SN values with equal accuracy compared with the relationship based on absorbance difference (A21B-A22b)-Here, the correlation between the two data sets was r = 0.953*** (n a 353). The spectrophotometric method is a rapid and simple means of measuring wort SN in the large numbers of samples generated by barley breeders and the single wave-length measurement offers a particularly efficient method of screening the very small wort volumes produced from test tube-scale mashes.

A model of the genetic differences in malting quality between European and North American barley cultivars based on a QTL study of the cross Triumph × Morex

“…The soluble nitrogen content of the wort (SOL N) was measured using a spectrophotometric method (Haselmore and Gill 1995) and expressed as a percentage. It was then used to calculate the Kolbach Index as a proportion of the total nitrogen content.…”

Analysing the contribution of component cultivars and cultivar combinations to malting quality, yield and disease in complex mixtures

“…PSY is a measure of the amount of alcohol obtainable from a tonne of malt. The soluble nitrogen content of the wort (filtered extract) was measured using a spectrophotometric method and expressed as a percentage (SN%) 22. These parameters were chosen not to provide a comprehensive measurement of malting quality, but because the study was concerned with the extent and evenness of modification.…”

“…The soluble nitrogen content of the wort (filtered extract) was measured using a spectrophotometric method and expressed as a percentage (SN%). 22 These parameters were chosen not to provide a comprehensive measurement of malting quality, but because the study was concerned with the extent and evenness of modification. Fermentability values peak at an earlier stage of modification than do values for HWE 23 and soluble nitrogen content provides a useful means of understanding the relationship between them.…”

The influence of steep regime and germination period on the malting properties of some hull-less barley lines

“…In addition, to provide a measure of filtration rate, the volume of wort collected after a 10 min filtration was recorded for each sample. Soluble nitrogen content of the wort was determined by a spectrophotometric method (19). The percentage soluble nitrogen was then used to calculate the soluble nitrogen ratio (SNR) as a proportion of the total nitrogen content (16).…”