Chemical and instrumental approaches to cheese analysis

Chemometrics-driven monitoring of cheese ripening: a multimodal spectroscopic and scanning electron microscopy investigation

The integration of spectroscopic techniques with chemometrics offers a means to monitor quality changes in dairy products throughout processing and storage. This study employed Attenuated Total Reflectance-Mid-Infrared Spectroscopy (ATR-MIR) coupled with Independent Components Analysis (ICA), and 3D Front-Face Fluorescence Spectroscopy (FFFS) paired with Common Components and Specific Weight Analysis (CCSWA). The research focused on Cheddar cheeses aged for 1, 2, 3, and 5 years, alongside Comté cheeses aged for 6, 9, and 12 months. The adopted approach offered valuable insights into the intricate cheese aging process within the food matrix. The ICA proportions and CCSWA scores highlighted the significant impact of biochemical transformations during maturation on the aging process. The extracted independent components (ICs) revealed variations in the vibration modes of amides, lipids, amino acids, and organic acids, facilitating the distinction between different cheese age categories. Additionally, CCSWA outcomes identified age-related differences through shifts in tryptophan fluorescence characteristics as the cheeses aged. These results were consistent with the observed alterations in the microstructure of cheese samples over time, corroborated by Scanning Electron Microscopy (SEM) imagery. The introduced multimodal methodology serves as a significant asset for determining the ripening stage of various types of cheese, offering a detailed perspective of cheese maturation beneficial to the dairy industry and researchers.

Elemental Fingerprinting of Pecorino Romano and Pecorino Sardo PDO: Characterization, Authentication and Nutritional Value

Sardinia, located in Italy, is a significant producer of Protected Designation of Origin (PDO) sheep cheeses. In response to the growing demand for high-quality, safe, and traceable food products, the elemental fingerprints of Pecorino Romano PDO and Pecorino Sardo PDO were determined on 200 samples of cheese using validated, inductively coupled plasma methods. The aim of this study was to collect data for food authentication studies, evaluate nutritional and safety aspects, and verify the influence of cheesemaking technology and seasonality on elemental fingerprints. According to European regulations, one 100 g serving of both cheeses provides over 30% of the recommended dietary allowance for calcium, sodium, zinc, selenium, and phosphorus, and over 15% of the recommended dietary intake for copper and magnesium. Toxic elements, such as Cd, As, Hg, and Pb, were frequently not quantified or measured at concentrations of toxicological interest. Linear discriminant analysis was used to discriminate between the two types of pecorino cheese with an accuracy of over 95%. The cheese-making process affects the elemental fingerprint, which can be used for authentication purposes. Seasonal variations in several elements have been observed and discussed.

The effect of milk fat substitution on the rheological properties of Edam-type cheese

In cheese-like products, milk components (in particular fat) are partially or completely replaced with non-dairy substitutes. An attempt was made in this study to determine whether Edam-type cheese can be distinguished from its substitute, where milk fat was replaced with palm oil, based on rheological properties. The rheological properties of Edam cheese and its substitute were analyzed during a 16-week ripening period, based on the results of a stress-relaxation test. The values of the rheological parameters were estimated with the use of the generalized Maxwell model and a non-linear model proposed by the authors, which accounted for the plastic deformation of the analyzed samples. The study revealed that both methods were equally effective in describing the stress relaxation process; therefore, they can be regarded as equivalent. Excluding the initial stage of ripening (which is not important from the consumers’ point of view), the replacement of milk fat with palm oil did not influence the rheological properties of Edam-type cheese and the cheese-like product. In subsequent stages of ripening, no significant differences were found in the rheological properties of both products, which could only be used to evaluate their ripeness.

Effect of composition and storage time on some physico-chemical and rheological properties of probiotic soy-cheese spread

Probiotic soy-cheese spread was prepared by fermenting soymilk with specific probiotic starter culture, and there after processing the coagulated mass. Soy cheese spread samples had more than 109 cfu/g of viable probiotic count at the time of preparation; and had around 17.6% protein, 25.3% fat and 19.8% total soluble sugar. Compared to commercially available dairy cheese spread, probiotic soy cheese spread had significantly higher protein and anti-oxidant activity. Soy cheese spreads, prepared from pure soymilk as well as by mixing with dairy milk, were studied with respect to the differences in their rheological behavior during storage at refrigerated conditions. A dynamic oscillatory test was used to measure the viscoelastic properties of spreads at 0, 7, 14, 21 and 28 days of storage. It was observed that the storage modulus (G') was higher than the loss modulus (G″) throughout the storage period indicating that the soy cheese spreads exhibit predominantly elastic behavior. The cheese spread sample prepared by adding okara in soymilk had the highest values of G' and complex viscosity (1120 Pa and 11.5 Pa s, respectively at an angular frequency of 100 s-1). G', G″ and viscosity of cheese spread did not change significantly up to 14 days, with values of 650, 225 Pa and 7.43 Pa s, respectively for the sample prepared from soymilk alone. However, these values increased thereafter which might be an indication of structural changes in the cheese spread samples.