GABRIELA GIANI PIERETTI

Título da Dissertação:  ASPECTOS TECNOLÓGICOS DE QUEIJO MINAS FRESCAL COM APLICAÇÃO DE COBERTURA COMESTÍVEL

Orientador: Profa. Dra. Grasiele Scaramal Madrona

Data da Defesa: 19/09/2014

RESUMO GERAL

 INTRODUCTION. Currently the consumer market is increasingly demanding and concerned with the quality of food and so industries are seeking ways to produce foods safer and with longer shelf life. Technological advances seen in the dairy segment in recent years are responsible for the diversity and quality of products available to consumers. Aware that the package is responsible for contain and protect the packaged product and ensure its conservation, the need arises for studies of new packaging and/or storage of edible coatings for cheese. Among the main polysaccharides used for forming hedges, sodium alginate has been extensively studied in use in films to cover food and preparation of food restructured. Another interesting factor is to realize the incorporation of essential oils in edible coating, a technique effective for food preservation, maintaining the appearance, taste, quality, thus increasing the commercial value of the products. Therefore, considering the antimicrobial properties and flavorings already known about Rosmarinus officinalis L (rosemary oil) and Origanum vulgare L. (oregano oil) was decided to work with these two essential oils, among the countless that currently exist, it is valid to point out though essential oils are recognized by FDA (Food and Drug Administration) as GRAS (Generally recognized as safe). Between types of foods, dairy products are among the most susceptible to contamination by microorganisms, in particular fresh artisan cheeses. To cause great economic losses and risk of causing foodborne illness, has studied ways to combat this contamination.
OBJECTIVES. Develop and evaluate the microbiological, physicochemical and sensory characteristics, texture, color, pH and mass loss of a fresh cheese, edible coating added to sodium alginate base and essential oils of oregano and rosemary.
MATERIALS AND METHODS. For the preparation of fresh cheese mines was following Good Handling Practices and Manufacture of food, and the base formulation cheese was 98.73% whole pasteurized milk, 1.15% salt, 0.1% and liquid rennet 0.02% calcium chloride. The edible coating was prepared from a 2% solution of sodium alginate. The incorporation of essential oils was made on the concentrations of 0.06% to 0.1% for oregano, and rosemary. Slices of fresh cheese mines were immersed in proper coating solutions (sodium alginate and / or essential oil of oregano and rosemary). 4 treatments that were performed were: cheese without coverage, with coverage to the base alginate and calcium chloride; with cover to the base alginate and calcium chloride with added essential oil of oregano to 0.06% and will cover basic alginate and calcium chloride with added essential oil of 0.1% rosemary.The samples were packed and stored in BOD 5 ° C for 30 days. Microbiological analyzes required under Brazilian law were made (coliforms to 45⁰C / g, staphylococcal coagulase positive / g, Salmonella sp / 25g and Listeria monocytogenes / 25 g) and also coliforms to 35⁰C / g; Physical and chemical (chemical composition), sensory (hedonic scale test of 9 points with 105 untrained, for color, taste, aroma and texture), texture and instrumental color, pH and mass loss kinetics (applying parameters kinetics 1st Order). The average results were submitted to analysis of variance (ANOVA) and means compared by Tukey test (p <0.05) for comparison between samples, and analysis of linear or quadratic regression to compare the retention times.

RESULTS AND DISCUSSION. Regarding microbiological analyzes, the results were satisfactory, considering legislation RDC nº12 of ANVISA. In chemical composition results, the moisture and carbohydrates showed differences when compared to the end of storage time and initial time and when compared between samples, in which the sample with edible coating and edible coating with oregano essential oil had lower moisture loss. When samples were bought only between them, only the analysis of lipids showed a significant difference between all samples. Regarding the texture, the sample without edible coating differed from the others presenting tenderer at the beginning of storage and at the end firmest when compared with others. For color analysis, both samples showed luminosity close to white color with yellow-green tones. In kinetic analysis of mass loss, the sample without edible coating differed from the others having an increased speed of mass loss. The pH values during storage showed no significant difference. Sensory analysis showed a good acceptance for all samples, especially for samples with edible coating added of oregano essential oil, which had notes above 7 for all attributes evaluated and the highest acceptance rate (87%).

CONCLUSIONS. The use of edible coatings added of rosemary and oregano essential oils had positive results in samples, reducing weight loss, improving tenderness (texture) and maintaining stable physico-chemical composition and pH. The microbiological evaluation showed satisfactory results, in accordance with current Brazilian law. The sensory evaluation obtained positive results (AI> 75%), highlighting the sample with edible coating added of oregano essential oil, which gave a satisfactory result in all items and higher acceptance rate. Thus, in general, the addition of edible coating with essential oil of oregano and rosemary is an option for technological improvements in quality parameters (microbiological, physicochemical and sensory) of Minas frescal cheese.

Key words: sodium alginate, oregano essential oil, rosemary essential oil

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