Flavour stability

The disadvantage of the dilution of extracts is that the flavour concentration is lower and the flavour dose has to be increased. Significant heat treatment can influence the flavour stability in a negative way because oxidation and Maillard reactions are enhanced and the flavour might be less stable. Owing to the fact that flavours are mainly complex mixtures, their rheological properties, particularly in presence of hydrocolloids, fibres or other macromolecules, are often not Newtonian. This can cause problems in the production process. In order to simplify... 

The low total polyunsaturation of canola oil, about 30% versus 58% for soybean oil, along with the high content of monounsaturates, about 60% versus about 25% for soybean oil, are responsible for the good flavour stability of this oil, despite the presence of linolenic acid. Additional minor, but important reasons, for better oxidative stability of canola oil compared with soybean oil are as follows ... 

Whenever we want to understand flavouring stability, we have to know something about ... 

The order of importance of these factors will vary from one type of beer to another and from brewery to brewery. Some consideration has already been given to selection of yeast strain in Chapter 18. It will be appreciated that the choice depends on many parameters. The requirements can be summarized as a yeast which will produce a beer of desired taste, aroma, flavour stability and brilliance, within an acceptable period of time in the equipment available, and without undue losses of beer during processing. 

The modification processes which will be described are hydrogenation, fractionation and interesterification. These processes are used to widen the applicability of oils and fats and also, in the case of hydrogenation, to make products of acceptable oxidative and flavour stability from unstable or relatively unstable raw materials. 

Enhanced flavour stability Elevated sulphur dioxide Over-expression of MET14 and SSUl Donalies and Stahl (2002)... 

Figure 4 EPR/lagtime time course of a beer sample (see text). Plotted is the peak-to-peak intensity of the spin adduct. The longer the lagtime value, the better the flavour stability. The converse is true for the T150 value.

Electron Paramagnetic Resonance (EPR, ESR) spectroscopy is a unique tool to answer specific questions evolving radical processes in both research and development (R D) as well as quality control (QC). Key QC examples comprise the food irradiation control for customer care according to European Union (EU) norms and the flavour stability and shelf life assessment on fresh beer. For the first time, an automated DPPH-assay to measure the effectiveness of antioxidants by CW-EPR is reported. 

Dufour, J.P. (1991) Influence of industrial brewing and fermentation working conditions on beer SO2 level and flavour stability. Proc. Eur. Brew. Conv., Lisbon, pp. 209-216. 

Hashimoto, N. (1981) Flavour stability of packaged beers. In Brewing Science, (ed Pollack, J.R.A.) pp. 348-401. 

Wheeler, R.E., Pragnell, M.J. and Pierce, J.S. (1971) The identity of factors affecting flavour stability in beer. In Proc. Congr. 13th Eur. Brew. Conv., Estoril, pp. 423-436. 

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