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Abstract: The use of near infrared spectroscopy (NIRS) technology employing a remote reflectance fibre-optic probe (with a 5cm×5cm quartz window) for the analysis of the hydrophilic (HI) and hydrophobic (HO) peptides and the ratio HO/HI was assayed. To do so, cheeses with known and varying percentages of cow’s, ewe’s and goat’s milk were elaborated (112 samples). Ripening controls were performed over 6 months, and the chemical data obtained by reversed-phase high performance liquid chromatography used as reference. The regression method employed was modified partial least squares (MPLS). The multiple correlation coefficients (RSQ) and prediction corrected standard errors (SEP (C)) obtained 0.879 and 1.83% for hydrophilic (HI) and 0.879 and 1.83% for hydrophobic (HO) peptides, respectively, and 0.890 and 0.03% for the ratio HO/HI. The method allows immediate control by direct application of the fibre-optic probe to the cheese without prior sample treatment or destruction. [Copyright &y& Elsevier]

Abstract: In the present work we studied the use of near infrared spectroscopy (NIRS) technology employing a remote reflectance fibre-optic probe (with a 5cm×5cm quartz window) for the analysis of the percentage of milk (cow''s, ewe''s and goat''s) used in the elaboration of cheeses with different ripening times. To do so, cheeses with known and varying percentages of cow''s, ewe''s and goat''s milk were elaborated (112 samples with milk collected in winter and 112 samples with milk collected in summer) and used as reference material, and ripening controls were performed over 6 months. The method allows immediate control of the cheese without prior sample treatment or destruction by direct application of the fibre-optic probe to the sample. The regression method employed was modified partial least squares (MPLS). Of all the samples (224), 200 formed to so-called calibration set and the other 24 were used for external validation. The calibration results obtained using 200 samples of cheese allowed the percentage of cow''s, ewe''s and goat''s milk to be measured. The multiple correlation coefficients (RSQ) and prediction corrected standard errors (SEP(C)) obtained were respectively, 0.834 and 11.6% for cow''s milk; 0.871 and 9.8% for goat''s milk; 0.880 and 10.6% for ewe''s milk. The ratio performance deviation (RPD) values obtained indicate that the NIRS equations can be applied to unknown samples. [Copyright &y& Elsevier]

Abstract: The objective of this work is to evaluate by near infrared reflectance (NIR) spectroscopy different attributes, visual (presence of holes), taste (salty, buttery flavour), texture (hardness, chewiness, creamy), rancid flavour and other sensations (pungency, retronasal sensation), in cheeses elaborated with milk of variable composition (cow, ewe, goat), collected in winter and summer and subject to ripening times of 4 and 6months, taking as reference data the evaluation of the sensorial properties obtained by a panel of eight trained experts. The sensorial properties are quantified by NIR spectra with a remote reflectance fibre optic probe applying the probe directly to the cheese samples and the calibration equations are developed by using modified partial least-squares (MPLS) regression for 50 samples of cheese. The robustness of the analytic method is confirmed by applying it to 14 samples of unknown cheeses. [Copyright &y& Elsevier]