Heat treatment of milk signifies a certain degree of protein denaturation, which modifies the functional properties of dairy products. Traditional methods for detecting and quantifying the denaturation of whey proteins are slow, complex and require sample preparation and qualified staff. The world’s current trend is to develop rapid, real-time analytical methods that do not destroy the sample and can be applied on/in-line during processing. This review presents the rapid methods that are being studied, developed and/or applied to determine and quantify the thermal denaturation of whey proteins, including spectroscopic, electrochemical and miniaturized methods. The selected methods save a significant amount of time and money compared to the traditional ones. In addition, the review emphasizes the methods being applied directly to milk and/or that have potential for on/in/at-line application. There are interesting options to quantify thermal denaturation of whey proteins such as biosensors, nanosensors and microchips, which have fast responses and could be automated. In addition, electrochemical sensors are simple to use and portable, while spectroscopy alternatives are suitable for on/in/at-line process.

Milk is subjected to different industrial processes, provoking significant physicochemical modifications that impact milk’s functional properties. As a rapid and in-line method, front-face fluorescence can be used to characterize milk instead of conventional analytical tests. However, when applying fluorescence spectroscopy for any application, it is not always necessary to determine which compound is responsible for each fluorescent response. In complex matrixes such as milk where several variables are interdependent, the unique identification of compounds can be challenging. Thus, few efforts have been made on the chemical characterization of milk’ fluorescent spectrum and the current information is dispersed. This review aims to organize research findings by dividing the milk spectra into areas and concatenating each area with at least one fluorophore. Designations are discussed by providing specific information on the fluorescent properties of each compound. In addition, a summary table of all fluorophores and references cited in this work by area is provided. This review provides a solid foundation for further research and could serve as a central reference.

A remarkable variety of cheeses are made in the US and Mexico, each with distinct sensory characteristics. Therefore, the objective of this study was to identify the sensory perception of eighteen varieties of cheeses, comprising eight manufactured in the US and ten manufactured in Mexico. Additionally, we evaluated the influence of the cultural context of the judges on the sensory profiles of different cheeses. Twelve semi-trained judges, divided equally between the US and Mexico, participated in intensive training during an exchange program held in both countries. The judges utilized sensory evaluation questionnaires in English, which encompassed three components: (1) the Rate-All-That-Apply (RATA) method, which assessed eighteen specific attributes of each cheese on a numerical scale from 1 to 10; (2) preliminary acceptability tests conducted using a 9-point hedonic scale; and (3) preliminary tests of willingness to buy the products, evaluated by a yes/no question. This study reveals the perception of the most popular cheeses made in Mexico and the US, where the main differences were in three attributes—elasticity, saltiness, and acidity—explained by different cheese-making practices. In general, a few significant differences were observed in the sensory perception of cheese based on the judges’ origins. The most notable differences were found in the cheeses manufactured in the US, particularly in terms of texture and taste attributes. This preliminary study identifies possible significant sensory trends in California, USA, and Aguascalientes, Mexico.

This study evaluated the effects of wine-soaking on cow’s milk pressed cheese properties and developed a standardized cheesemaking procedure. Cheese was soaked in Cabernet Sauvignon and Alicante Bouschet red wines for two soaking periods of four days after the brining process. The physicochemical, microbiological, and volatile composition were evaluated, along with consumer sensory evaluation. After 60 days of ripening, wine-soaked cheeses had statistically lower salt and moisture levels, with higher protein and fat content than the unsoaked cheeses. Alicante Bouschet cheeses have a darker purple-red color than Cabernet Sauvignon. The microbiological analysis found no significant differences across treatments and samplings. The most representative volatile compounds in wine-soaked cheeses were esters and ketones. Principal Components Analysis on the volatile compounds showed a clear separation between the two wine-soaked cheeses and the control cheese. For example, Cabernet-soaked cheese had higher levels of phenylethyl alcohol and 2-phenylethyl acetate (floral aromas), while Alicante-soaked cheese was distinguished by nonanal (fruity and grassy aroma). Sensory results showed preferences for the overall liking, flavor, and rind color for the wine-soaked cheeses over the control. Consequently, a standardized recipe for wine-soaked pressed cheese was developed, along with specific parameters for the soaking process to ensure a well-received product.

Whey is widely used across various food industries, and its functional properties are critical for product quality and consumer acceptance. The current study aimed to assess the feasibility of using front-face fluorescence spectroscopy (FFF) as a nondestructive technique to predict the technological functionality of whey, particularly its foaming, gel-forming, and emulsifying capabilities. Heat treatments were applied on reconstituted skim milk enriched with whey protein isolated (80°C with 7 holding times) to induce variability in all the studied functional properties. Then, whey samples were obtained by isoelectric precipitation of caseins from enriched milk. Synchronous FFF of whey was measured at an excitation of 250 to 550 nm (λ₀ = 20 nm and Δλ = 10 nm, where λ₀ = initial delta marks the first emission scan at a specific excitation; because the excitation was set at 250 nm, the first emission was at 270 nm. Δλ = delta increment is the change in wavelength for each subsequent scan). Excitation and emission wavelengths and maximum intensities were collected for 10 areas. These FFF parameters and their mathematical transformations were used in the maximum R² procedure of SAS software (version 9.4, SAS Institute Inc.) to select the predictors and obtain the best models, which were cross-validated. Excellent prediction models (R² > 0.95, ratio of performance deviation [RPD] >4) were obtained for gel-forming and emulsifying properties. However, for foam properties, the obtained models were successful for foam overrun (0.90 ≤ R² ≤ 0.95, 3 ≤ RPD ≤4) and moderately successful (0.80 ≤ R² < 0.90, 2.25 ≤ RPD <3) for foam stability. This research demonstrated that FFF spectroscopy has the potential to become a method for assessing whey functional properties, leading to improved industry process control and new products.