Impacto da modificação da temperatura de armazenamento do leite nos rendimentos e qualidade do queijo

Abstract

One of the main goals in a company is profitability, the more they explore their resources the better the company’s outcomes. Bel is the leader in the Portuguese cheese market hence, their strategic plan is focused on their resources efficiency, for this reason this project emerged. Focusing on the volumes of milk labored per year, after some research, it came out the possibility of increasing yields changing milk storage temperatures. The objective is to study to what extent does rising storage temperature (to 9-11˚C, 12-15 before manufacturing) will affect the protein retention on the cheese yields compared to its current storage temperature (2-6˚C). To explore the effects of temperature on cheese yields the experimentations occurred during different times of the year which attach diverse qualities to the primary resource, the milk. Due to this seasonal variation, addition of powder milk was required to fulfill the production plan. These adjustments will be considered and the two recipes will be separated and compared regarding the yields. The yields were calculated in the perspective of usefulness of the protein (percentage of milk protein that was recovered in cheese). Throughout the study, it became relevant to explore the impact of certain variables such as: duration of the flocculation, pH after 5 hours of production, delays in production, the ratio of fat/protein matter in milk, milk’s age, percentage of vertical working vats used in the production and obviously, the storage temperature of milk. The conclusion of this study was that the rise of storage temperature was only effective in increasing the yields of recipes with addition of powder milk. The sensorial analyses revealed that there was no significate difference between the two products (2-6˚C versus 9- 11˚C; 12-15 hours before manufacturing). Regarding the microbiological analyses, a prevention plan has been developed to control the growth of psycrotrophic bacteria allowing an appropriate forecast of the effects of these bacteria over the product. This thesis also presents a statistical analysis regarding Bel Portugal production data from 2016 and 2017 for the studied product. The analysis focuses on the acknowledgement of the variables that have a statistically significance over the cheese yields.

Date of Award	8 Nov 2018
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Arlindo Reis (Supervisor) & Ana Maria Gomes (Co-Supervisor)