Estudo de desenvolvimento de um sistema de embalagem ativa para queijo Marinhas

Abstract

The cheese is a food that makes part of human diet for thousands of years, is solid and is made from cows, goats, sheep and/or other mammal’s milk. There are hundreds of cheese types produced around the world, including the Marinhas cheese. Marinhas cheese differentiates itself by its distinctive and unmistakable flavor, this is a handmade cheese without anti-mold chemicals adding. However, the production company currently faces a cheese conservation problem due to mold appearing on its surface. The properties of chitosan coatings regarding antimicrobial activity have been intensively studied as reported in published literature (Balicka-Ramisz et al. 2005; Raafat et al. 2008; Dutta et al. 2012). It can be applied as coating directly on the food or associated with others materials. Chitosan represents a good example of an active packaging. This work aimed at studying the effect of chitosan coating on Marinhas cheese on protecting surface mold development. To evaluate the mold development, it was used image analyses tools, CellProfiler (www.cellprofiler.org). The Marinhas cheese has been subject to physico-chemical properties characterization tests. The fungus was also identified through DNA testing performed by Biopremier as being Penicillium raistrickii. In order to evaluate the chitosan coating effect on fungal growth, two different approaches were followed. In the first, at Biotechnology Superior School, a yeast extract agar plates were placed in contact with paper coated with different chitosan concentrations. In the second, at Biotechnology Superior School and at Lacticínios das Marinhas factory, chitosan coating was applied directly on the cheese. In experiments with plates (first experimental approach), it was verified that fungus appearing is delayed and the temperature played an important role. In the second approach doesn't happened the same. In the cheese experiences, wasn’t possible verify a positive effect on surface mold inhibition or retardment. Therefore, it’s conclude that this coating application doesn’t solve the mold appearance on cheese Marine problem, so an alternative approach should be followed.

Date of Award	2014
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Maria de Fátima Poças (Supervisor)