Abstract
The difference of fermentation types, homo-and hetero-types, is one of the most important key to classify the genus of lactic acid bacteria. The new method which can discriminate correctly both fermentation types of homo-or hetero-type by using near infrared spectroscopy has been investigated. Spectral data (raw and second derivative) of supernatants of 10 lactic acid bacterial type strains (calibration set) were subjected to discriminant analysis with Mahalanobis distances principals. A discriminant function with second derivative absorbance at the wavelengths of 2272nm and 2311nm was derivated, which produced a sum of inverse squared distance of 0.06. This function could be successfully used to discriminate between homo-type and hetero-type of validation set of lactic acid bacteria and of strains isolated from Miso-paste products. It was suggested that 2272nm was key wavelength associated with lactic acid and ethanol. By this method, the fermentation types could be classified using a little amount of culture supernatant (5ml) within 5 min.
