蛍光分光法を用いたビール酵母活性のモニタリング

抄録

    The activity of beer yeast greatly influences the quality of beer. It is necessary to measure the activity of beer yeast rapidly and accurately. Fluorescence spectroscopy can be used to measure activity of a substance easily, rapidly, and nondestructively. The purpose of this study was to evaluate the activity of beer yeast by using fluorescence spectroscopy. We investigated the relationship between beer yeast activity and the peaks of fluorescence emission intensity spectra obtained by fluorescence spectroscopy performed on mash samples. We found that the best excitation and detection wavelengths for investigating beer yeast were 425 and 635 nm, respectively. The fluorescence may have been induced by beer yeast because no fluorescence peaks were detected from mash from which the beer yeast had been removed. Furthermore, this peak was not affected by differences in the concentrations of glucose and alcohol or by the different strains of beer yeast. Then we examined the relationship between the curvature degree of the fluorescence peak and the viability of the beer yeast. A positive correlation was observed between the degree of curvature of the peak and the number of live cells. In addition, a positive correlation was observed between the number of live cells and ATP production in beer yeast. Therefore, it was suggested the degree of curvature of the peak is also related closely with ATP production of beer yeast. Thus, our study shows that fluorescence spectroscopy is a suitable method for evaluating the degree of activity of beer yeast easily, rapidly, and nondestructively.