Estimation of Alpha Amino Nitrogen

Raising the temperature from 16°C to 20°C or 25°C for prolonged periods during steeping or germination reduces HWE and TSN and slows down wort separation in laboratory mashes. When the higher temperatures are applied only during the last steep or the first two days of germination the initial rate of modification is accelerated, as is the development of a-amylase and endopeptidase. After four or five days germination the levels of enzyme activity are substantially lower than in the control malt. However, some barleys give malts with acceptable standard analyses after 4 rather than 5 days of germination.

Section: Methodsmentioning

confidence: 99%

Effects of Raised Temperatures During Steeping and Germination on Proteolysis During Malting

Baxter¹,

O'Farrell²

1980

“…Fatty acids were estimated as their methyl esters by the method of Buckcc and MacPherson. 5 The general findings of the study may be sum marized in terms of the vector diagram in Fig. 1.…”

Section: Resultsmentioning

confidence: 95%

Caprylic Flavour as a Feature of Beer Flavour

Clapperton

Brown

1978

Self Cite

Caprylic flavour is part of the distinctive overall flavour of a large proportion of beers in trade. The flavour occurs in the majority of lager beers and in about 20% of ales. It is correlated with the levels of octanolc acid and decanoic acid present in beer. Lager yeasts (S. uvarum) tend to liberate larger amounts of these two fatty acids during fermentation than do ale yeasts (S. cerevisiae). The flavour significance of these acids has been determined by correlating the results of sensory and instrumental analyses and also by adding the purified acids to beer. Implications of these two methods for assessing the flavour significance of chemical constituents of a complex product are discussed.

Sterol Synthesis in Relation to Growth and Fermentation by Brewing Yeasts Inoculated at Different Concentrations

Aries¹,

Kirsop²

1977

The sterol contents of brewing yeasts harvested from an anaerobic fermentation and inoculated into air-saturated wort rise rapidly from ca. 1 mg/g dry yeast to ca. 10 mg/g and remain at this level until the oxygen is absorbed. After all oxygen is removed from the medium, sterol synthesis ceases and the concentration in the cells declines as growth occurs until a limiting value is reached, when reproductive growth ceases. In the presence of oxygen, sterols are present primarily as sterol esters; free sterols accumulate after oxygen uptake is complete. The total quantity of sterol which is synthesized in the presence of oxygen determines the extent of subsequent yeast growth. It is shown that the magnitude of sterol synthesis in the yeast population as a whole is influenced by the pitching rate.