Identity Confirmation of a Branded, Fermented Cereal Product by UV Spectroscopy: A Feasibility Study Involving a Trappist Beer

Jittima Weeranantanaphan¹ and Gerard Downey^2,*
¹ Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland.
² Teagasc, Ashtown Food Research Centre, Dublin 15, Ireland.
^* Corresponding author. E-mail: gerard.downey@teagasc.ie.

J. Inst. Brew. 116(1), 56–61, 2010 | VIEW ARTICLE

ABSTRACT
Brand protection is important for a food processor; trust in brand identity is essential for consumer confidence. In this study, the combination of UV spectroscopy and multivariate mathematics was investigated to confirm the identity of a processed cereal product—a Trappist beer. Samples (52) of Rochefort 8, other Rochefort and non-Rochefort beers, diluted 1:100 with distilled water, were analysed by UV spectroscopy (220–400 nm). Partial least squares discriminant analysis (PLS-DA) and soft independent modelling of class analogy (SIMCA) multivariate methods were applied separately to confirm the identity of Rochefort 8 beer. Spectral data were analysed in both raw and standard normal variate (SNV) pre-treated forms. Using PLS-DA, a twostage modelling procedure was applied involving initial classificatio nas either Rochefort or non-Rochefort followed by classification within the Rochefort class as Rochefort 8 or non-Rochefort 8. Correct classification rates for these two steps were (a) 100 and 94.4% and (b) 90.9 and 100% respectively. Applying the 3 principal component SIMCA model to the 8 test Rochefort and all of the non-Rochefort (n = 36) samples, 6 of the 8 Rochefort beers were correctly classified (75%; p = 0.05) but only two of the 36 non-Rochefort beers were wrongly classified as Rochefort (correct classification rate of 94.4%).

Key words:
beer, chemometrics, identification, Trappist, UV spectroscopy.