Ripening, cheese monitoring

Different authors used RP-HPLC and UV detection to monitor peptide formation during cheese ripening [174-178], providing valuable information about proteolysis. When large hydrophobic peptide need to be separated an lEC represents the best choice [179]. Nevertheless, the identification of these peptides is essential for the complete understanding of the proteolytic process. The peptides eluted from the LC column can be subjected to ESl-MS for molecular weight determination and MS/MS for amino acid sequence determination, which allow rapid peptide identification [172]. HPLC-ESl-MS and MS/MS techniques have been successfully used for peptide mass fingerprint purposes for sequence analysis of purified albumin from Theobroma cacao seeds [180,181]. 

Contents I. Introduction 168 II. Sampling Techniques 168 III. Compositional Analysis 169 A. Moisture and total solids 169 B. Fat 171 C. Protein 171 D. Ash 172 E. Salt and chloride content 172 F. Acidity and pH 172 G. Calcium and phosphorus 173 IV. Monitoring Cheese Ripening 173 A. Assessment of lactose, lactate, and citrate metabolism 174 B. Assessment of lipolysis 178 C. Assessment of proteolysis 180 D. Assessment of smaller breakdown products 194 V. Novel and Rapid Instrumental Methods 196 VI. Concluding Remarks 200 References 201... 

GC combined with mass spectroscopic (MS) detection provides very accurate identification and quantification of FFAs. Pinho et al. (2003) monitored changes in the FFA content during the ripening of ewe cheese. Sampling was done by headspace solid-phase microextraction (SPME). An excellent correlation was observed between the initial concentration of the sample and the amount absorbed on the SPME fiber. SPME sampling was done at 65 °C with a fiber coated with 85-p.m polyacrylate film. After equilibration at 65 °C for 40 min, the fiber was exposed to the sample headspace for 20 min and inserted into the GC port. Despite its accuracy, the GC-MS method is not widely used, presumably because of its cost and complexity. 

The ability of MIR to monitor fundamental vibrations of several functional groups provides a new tool for researchers to look at minor compounds in cheese. Some of its early applications were focused on the analysis of macromolecules in cheese such as fat, moisture, and protein (Chen et ah, 1998 McQueen et ah, 1995). More recently, the chemical parameters of cheese (Martfn-del-Campo et ah, 2007), composition (Rodriguez-Saona et ah, 2006), protein structure and interactions during ripening (Mazerolles et ah, 2001), and ripening of Swiss cheese (Martin-del-Campo et ah, 2009) were analyzed with improved techniques. Almost all attempts have been directed toward the determination of macromolecules in cheese. This is mainly because of difficulties in sampling procedures and the heterogeneous nature of cheese (McQueen et ah, 1995) that make analysis of minor compounds difficult. 

Chen, G., Kocaoglu-Vurma, N. A., Harper, W. J., and Rodriguez-Saona, L. E. (2009). Application of infrared microspectroscopy and multivariate analysis for monitoring the effect of adjunct cultures during Swiss cheese ripening. J. Dairy Sci. 92,3575-3584. 

Chin, H. W. and Rosenberg, M. (1998). Monitoring proteolysis during Cheddar cheese ripening using two-dimensional gel electrophoresis. J. Food Sci. 63,423-428. 

Kaiser, K. P., Belitz, H. D., and Fritsch, R. J. (1992). Monitoring Cheddar cheese ripening by chemical indices of proteolysis. Z. Lebensm.-Unters. Forsch. A 195, 8-14. 

Mazerrolles, G., Devaux, M. F., Duboz, G., Duployer, M. H., Riou, N. M., and Dufour, E. (2001). Infrared and fluorescence spectroscopy for monitoring protein structure and interaction changes during cheese ripening. Lait 81, 509-527. 

Subramanian, A. (2009). Monitoring flavor quality, composition and ripening changes of Cheddar cheese using Fourier-transform infrared spectroscopy. PhD Thesis, The Ohio State University, p. 121. 

Altemueller, A.G., Rosenberg, M. 1996. Monitoring proteolysis during ripening of full-fat and low-fat Cheddar cheese by reverse-phase HPLC. J. Food Sci. 61, 295-298. 

Danish blue cheese [24] Monitoring the ripening process 14 conducting polymers... 

J. Tiihaas, P.V. Nielsen, Electronic nose technology in quality assessment Monitoring the ripening process of Danish blue cheese. J. Food Sci. 70, E44-E49 (2005)... 

Karoui R, Dufour E, De Baerdemaeker J. Monitoring the molecular changes by front face fluorescence spectroscopy throughout ripening of a semi-haid cheese. Food Chem 2007 104 409-20. 

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