Acta Vet. Brno 2013, 82: 191-196

Rapid assessment of selected free amino acids during Edam cheese ripening by near infrared spectroscopy

Jiří Mlček1, Květoslava Šustová2, Otakar Rop3, Tünde Juríková4, Petr Humpolíček5, Štefan Balla4

1Tomas Bata University, Faculty of Technology, Department of Food Technology, Zlín, Czech Republic
2Mendel University, Faculty of Agronomy, Department of Food Technology, Brno, Czech Republic
3College of Business and Hotel Management, Department of Gastronomy, Brno, Czech Republic
4Constantine the Philosopher University, Faculty of Central European Studies, Institute of Natural and Informatics Sciences, Nitra, Slovakia
5Tomas Bata University, Centre of Polymer Systems, Polymer Centre, Zlín, Czech Republic

The study focuses on rapid determination of free amino acids produced during the ripening of cheese, by using near infrared spectroscopy. Analyses of 96 samples of Edam cheese (30% and 45% of fat in dry matter) were performed at monthly intervals up to the ripening age of 6 months. In total, 19 amino acids were analysed with infrared spectrometer using two different methods, either in the regime of reflectance in the integrating sphere of the apparatus or using a fibre optic apparatus with the fibre optic probe. Reference data based on high-performance liquid chromatography were used for calibration of the spectrophotometer. Calibration models were developed using a partial least square algorithm and tested by means of cross-validation. When measured with the integrating sphere and with the probe, the values of correlation coefficients ranged from 0.835 to 0.993 and from 0.739 to 0.995, respectively. Paired t-test did not show significant differences between the reference and predicted values (P < 0.05). The results of this new calibration method showed the possibility of near infrared technology for fast determination of free amino acids, which occur during the ripening of Edam cheese. The content of free amino acids allow us to prepare Edam cheese quickly and efficiently for sale or to prepare the material for processed cheese.


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