Monitoring the ripening attributes of Turkish white cheese using miniaturized vibrational spectrometers.

Monitoring the ripening process by prevalent analytic methods is laborious, expensive, and time consuming. Our objective was to develop a rapid and simple method based on vibrational spectroscopic techniques to understand the biochemical changes occurring during the ripening process of Turkish white cheese and to generate predictive algorithms for the determination of the content of key cheese quality and ripening indicator compounds. Turkish white cheese samples were produced in a pilot plant scale and ripened for 100 d, and samples were analyzed at 20 d intervals during storage. The collected spectra (Fourier-transform infrared, Raman, and near-infrared) correlated with major composition characteristics (fat, protein, and moisture) and primary products of the ripening process and analyzed by pattern recognition to generate prediction (partial least squares regression) and classification (soft independent analysis of class analogy) models. The soft independent analysis of class analogy models classified cheese samples based on the unique biochemical changes taking place during the ripening process. partial least squares regression models showed good correlation (RPre = 0.87 to 0.98) between the predicted values by vibrational spectroscopy and the reference values, giving low standard errors of prediction (0.01 to 0.57). Portable and handheld vibrational spectroscopy units can be used as a rapid, simple, and in situ technique for monitoring the quality of cheese during aging and provide real-time tools for addressing deviations in manufacturing.

A rapid method for detection adulteration in goat milk by using vibrational spectroscopy in combination with chemometric methods.

Because of the second place of milk adulteration in the food fraud lists, the study focused on the investigation of the cow milk as an adulterant in goat milk based on ß-carotene presence in cow milk as s rapid method by Raman and Infrared spectroscopy with chemometric techniques.t Partial least squares regression (PLSR) and the soft independent modelling of class Analogy (SIMCA) models have developed to for the prediction of adulteration ratio and ß-carotene content of mixtures on the spectral band at around 1373, 1454, and 956 cm-1 for infrared and 1005, 1154, and 1551 cm-1 for Raman spectroscopy respectively. The correlation coefficient for calibration (R2cal), standard error of calibration, standard error of performance, and correlation coefficient for validation (R2val) have calculated for mid-infrared and Raman techniques. The PLSR models showed excellent fit (R2 value > 96) and could accurately determine ß-carotene content and percentage of spiked milk in a short time. SIMCA results showed that 20% intervals of the mixture could be differentiated barely from other mixtures by mid-infrared spectroscopy; however, there could not found significant discrimination by Raman spectroscopy. ß-carotene could be considered as a biomarker of determination of adulteration concerning ß-carotene content and mixture percentage, and discrimination of spiked mixture for the differentiation of goat and cow milk.

Monitoring Turkish white cheese ripening by portable FT-IR spectroscopy.

The biochemical metabolism during cheese ripening plays an active role in producing amino acids, organic acids, and fatty acids. Our objective was to evaluate the unique fingerprint-like infrared spectra of the soluble fractions in different solvents (water-based, methanol, and ethanol) of Turkish white cheese for rapid monitoring of cheese composition during ripening. Turkish white cheese samples were produced in a pilot plant scale using a mesophilic culture (Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris), ripened for 100 days and samples were collected at 20-day intervals for analysis. Three extraction solvents (water, methanol, and ethanol) were selected to obtain soluble cheese fractions. Reference methods included gas chromatography (amino acids and fatty acid profiles), and liquid chromatography (organic acids) were used to obtain the reference results. FT-IR spectra were correlated with chromatographic data using pattern recognition analysis to develop regression and classification predictive models. All models showed a good fit (RPre ≥ 0.91) for predicting the target compounds during cheese ripening. Individual free fatty acids were predicted better in ethanol extracts (0.99 ≥ RPre ≥ 0.93, 1.95 ≥ SEP ≥ 0.38), while organic acids (0.98 ≥ RPre ≥ 0.97, 10.51 ≥ SEP ≥ 0.57) and total free amino acids (RPre = 0.99, SEP = 0.0037) were predicted better by using water-based extracts. Moreover, cheese compounds extracted with methanol provided the best SIMCA classification results in discriminating the different stages of cheese ripening. By using a simple methanolic extraction and collecting spectra with a portable FT-IR device provided a fast, simple, and cost-effective technique to monitor the ripening of white cheese and predict the levels of key compounds that play an important role in the biochemical metabolism of Turkish white cheese.