Desenvolvimento e processamento por alta pressão hidrostática de queijo Minas Frescal incorporado com cenoura

Abstract

Consumers are increasingly becoming more critical in the selection of a food product, by mainly considering sensory, nutritional and safety issues in the decision to purchase. As a result, less drastic preservation methods have been more deeply investigated and broadly adopted in industrial scale, including the addition of natural antimicrobials and the high hydrostatic pressure processing. In this sense, the objective of the this study was to evaluate the effect of the incorporation of carrot either individually or in combination with high pressure tretament on the inhibition of Listeria innocua inoculated in Minas Frescal cheese, besides evaluating the effect on the proximate composition, carotenoids content and sensorial characteristics and acceptance. A 22 factorial design was first employed to perform the chemical and physical characterization, being the independent variables the pressure (0 and 500 MPa) and the carrot concentration (0% and 6%), with three repetitions of the central point. The following analyses were carried out in the cheeses resulting from the treatments: proximate composition (moisture, protein, ethereal extract, fixed mineral residue - FMR); instrumental color; carotenoid quantification (total carotenoids, lutein, α-carotene and β-carotene) and enumeration of Listeria innocua. For the sensory analysis, a full factorial design was adopted, by considering the central points of the first design as factors themselves. The global acceptance was evaluated by a 9-point hedonic scale and the CATA Test (check-all-that-apply) with 102 consumers. High pressure processing at the level of 500 MPa for 10 minutes reduced the Listeria innocua count from 7 log cfu /ml up to undetectable levels, without further sigificant increase along the chilled storage at 8 °C for 22 days. On the contrary, the single carrot incorporation (6%) or its combination in the level of (3%) with pressure treatment at (250 MPa) had no effect on the inhibition of this microorganism. Moisture content, protein, ethereal extract and FMR were not significantly affected by either the carrot incorporation or the high pressure processing. As expected, carrot addition enhanced the levels of total carotenoids, lutein, α-carotene and β-carotene, as well as affected the instrumental color parameters. There again, high pressure processing had no significant effect on these compounds. Furthermore, high hydrostatic pressure processing did not influence the overall acceptance of the samples, while the incorporation of 6% of carrot tended to lower the acceptance. In the analyzis of individual consumers, the cheese with 3% of carrot processed at 250 MPa did not differ from the control sample, which was the most preferred sample. According to the CATA test, the consumers were able to sensory characterize and differentiate between the cheeses with or without the addition of carrot.