0239–3006/$ 20.00 © 2012 Akadémiai Kiadó, Budapest Acta Alimentaria, Vol. 41 (3), pp. 351–362 (2012) DOI: 10.1556/AAlim.41.2012.3.7 ApplicAtion of ft-niR spectRoscopy on the deteRminAtion of the fAt And pRotein contents of lyophilized cheeses J. Lénárt, t. Szigedi, M. dernovicS and M. Fodor* department of Applied chemistry, corvinus University of Budapest, h-1518 Budapest, p.o. Box 53. hungary (Received: 9 december 2011; accepted: 15 may 2012) fourier transform near infrared spectroscopy (ft-niR) has been developed for determining the fat and protein contents of hard, semi-hard and processed cheeses. multivariate calibration models were carried out by partial least squares (PLS) regression. The diffuse refection spectra of different type of lyophilized cheeses were measured by ft-niR analyser in the 800–2500 nm spectral range. the calibration set of 62 samples were validated by leave-one- out cross-validation and by prediction set of 31 samples. the optimal result for fat content (root mean square error of cross-validation (RmsecV)=1.0; R 2 =99.1%, pls factor= 6) was obtained when the spectra were preprocessed by frst derivation (FD) combined with multiplicative scatter correction (MSC) and smoothing. The optimal result for protein content (RmsecV=1.4, R 2 =97.2%, PLS factor=6) was observed when the frst derivation combined with straight line subtraction (sls) and smoothing spectral preprocessing method was applied. Keywords: cheese, FT-NIR, fat, protein, lyophilisation, freeze-drying A wide variety of hard, semi-hard and processed cheeses are available on the market which products’ most important parameters are the fat and protein content. As a consequence of new nutritional trends recommending to consume less calories, cheeses of low fat content also become more popular but most of these types of cheeses contain large amount of fat (40–60 w/w%) which primarily determines the value of these products. the milk fat content shall be declared in a manner found acceptable in the country of sale to the fnal consumer, either as a percentage by mass, as a percentage of fat in dry matter, or in grams per serving as quantifed in the label provided that the number of servings is stated (codeX AlimentARiUs, 2007). Uncommonly there cannot be found any hints on the regulation of the protein content; however, it has a signifcant role in the balanced diet. the classical methods used in the standards on the determination of fat (iso, 2004) and protein (iso, 2008) have numerous disadvantages like they are time and energy consuming, have limited sample throughput and harmful effects on the environment mainly because of the large amount of chemicals required. developing a new method replacing the existent methods is a relevant problem. completing these requirements to avoid the mentioned disadvantages, the ft-niR method seems to be an appropriate solution (KaFFka, 2008). Advantage of this type of calibration is the amount of spectral information used, so that even minor differences in the sample spectra can be identifed (Zardetto, 2005). Because of the mentioned advantages of the ft-niR spectroscopy, it was already applied by several scientists on the determination of main components of dairy products like cheese (mcQueen et al., 1995; Rodriguez-otero et al., 1995; Karoui et al., 2006; GonzaLez-martin * to whom correspondence should be addressed. phone: +3614826165; fax: +3614664272, e-mail: marietta.fodor@uni-corvinus.hu