| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 2.17 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
A alheira é um enchido tradicional que está ligado à cultura e aos costumes das populações da região de Trás-os-Montes, cujos registos de fabrico remontam ao século XV. Atualmente, a produção de alheiras assume um papel importante na economia regional e nacional, pelo que é muito importante estudar e caracterizar as propriedades físico-químicas e microbiológicas para assegurar a qualidade das alheiras tradicionais. Deste modo, este trabalho teve dois objectivos principais: (i) estudar as características físico-químicas e microbiológicas ao longo do processo de fabrico de alheiras produzidas na região de Trás-os-Montes; e (ii) definir um mapa de qualidade, tendo em consideração as características físico-químicas e microbiológicas das alheiras produzidas de forma artesanal.
Para alcançar o objetivo 1 (Estudo 1), foram colhidas amostras, constituídas por cinco alheiras em três pontos de amostragem, em três lotes da cozinha de VINHAIS e em dois lotes da cozinha de BRAGANÇA. Os três pontos de amostragem foram efetuados no dia do enchimento, no meio do processo de maturação e no fim do processo de maturação, portanto as alheiras estavam prontas para a venda.
Para o objetivo 2 (Estudo 2), foi delineado um trabalho de amostragem de alheiras artesanais produzidas e comercializadas na região de Trás-os-Montes. Assim, foram adquiridas cinco alheiras de quinze produtores regionais, todavia apenas são apresentados os resultados de seis produtores, uma vez que a pandemia COVID-19 nos impediu de concluir as análises físico-químicas e microbiológicas em tempo útil para a conclusão desta dissertação.
Os resultados do Estudo 1 revelaram que as alheiras do produtor de BRAGANÇA apresentaram maior (p<0,05) aw (0,991 versus 0,985) e teor humidade (51,9 versus 48,9%) e menor (p<0,05) pH (5,42 versus 5,54) que as alheiras do produtor de VINHAIS. Como esperado, ao logo do processo de maturação observou-se uma diminuição (p<0,05) destes parâmetros, pelo que os valores mínimos foram obtidos nas alheiras prontas para comercialização. Já na composição proximal, as alheiras do produtor de BRAGANÇA apresentaram maiores (p<0,05) teores de proteína bruta (9,82 versus 9,40%) e de cinzas (1,47 versus 1,40%) que as alheiras do produtor de VINHAIS. Já o teor de gordura bruta não diferiu (p>0,05) entre produtores (22,7 versus 22,5%) e as alheiras do produtor de VINHAIS apresentaram maior (p<0,05) teor de hidratos de carbono (14,2 versus 17,8%). Os microrganismos avaliados neste trabalho foram os mesófilos, coliformes, Escherichia coli, Staphylococcus aureus, Clostridium perfringens e Salmonella spp. As alheiras do produtor de BRAGANÇA apresentaram contagens superiores de mesófilos (6,69 versus 5,45 log ufc/g) e de S. aureus (3,34 versus 2,90 log ufc/g) que as alheiras do produtor de VINHAIS. As alheiras de ambos os produtores apresentaram contagens baixas de coliformes, de E. coli e de C. perfringens. É também de salientar que foi detectada a presença de Salmonella em quatro alheiras das 75 analisadas. Ao longo do processo de maturação as contagens de todos os microrganismos aumentaram de forma gradual.
Os resultados do Estudo 2 evidenciaram uma elevada variação nos parâmetros físico-químicos estudados entre as alheiras dos diferentes produtores, o pH variou entre 3,39 e 4,62 e aw entre 0,974 e 0,991. Todas as alheiras analisadas apresentaram contagem de mesófilos superior a 6,5 log ufc/g. A análise de componentes principais identificou duas componentes que explicaram 55,5% da variação nas 11 variáveis originais. Cabe destacar que os três microrganismos patogénicos analisados, Salmonella, S. aureus e C. perfringens estão positivamente correlacionados entre si, o que indica que as más condições de higiene e as práticas de fabrico pobres são responsáveis pelas incidências destes microrganismos patogénicos.
As alheiras artesanais apresentam elevada variabilidade nas características físico-químicas e microbiológicas. A dimensão da segurança microbiológica é essencial para a valorização destes produtos, pelo que a melhoria do processo de fabrico e o seguimento das boas práticas de higiene, em todas as etapas de elaboração, são fundamentais para garantir tanto a estabilidade microbiológica como a segurança das alheiras.
Alheira is a traditional sausage that is linked to the culture and customs of the people of the Trás-os-Montes Portuguese region, whose manufacturing records date back to the 15th century. Currently, the production of alheiras plays an important role in the regional and national economy, so it is very important to study and characterize the physicochemical and microbiological properties to ensure the quality of traditional alheiras. Thus, this work had two main objectives: (i) to study the physicochemical and microbiological characteristics of alheiras throughout the manufacturing process of sausages elaborated by two artisanal producers, one in BRAGANÇA and the other in VINHAIS; and (ii) to construct a quality map, taking into account the physicochemical and microbiological characteristics of artisanally produced alheiras. In order to achieve objective 1 (Study 1), samples were taken, consisting of five sausages from three sampling points, three batches from the VINHAIS producer and two batches from the BRAGANÇA producer. The three sampling points were made on the day of stuffing, in the middle of the maturation process and at the end of the maturation process. For objective 2 (Study 2), a sampling scheme of artisanal sausages produced and marketed in the region of Trás-os-Montes was designed. Five alheiras were acquired from fifteen regional producers, however only the results of six producers are presented in this thesis, since the pandemic COVID-19 prevented us from completing the laboratorial analyses in time for the conclusion of this dissertation. The results of Study 1 revealed that the alheiras from the BRAGANÇA producer had a higher (p<0.05) water activity (0.991 versus 0.985) and moisture content (51.9 versus 48.9%) and lower (p<0.05) pH (5.42 versus 5.54) than that of VINHAIS producer. As expected, during the maturation process, a decrease (p<0.05) in these parameters was observed, so that the minimum values were obtained in the sausages ready for commercialization. On the other hand, in the proximate composition, the alheiras from the producer of BRAGANÇA had higher (p<0.05) contents of crude protein (9.82 versus 9.40%) and ashes (1.47 versus 1.40%) than the alheiras from the VINHAIS producer. The crude fat content did not differ (p>0.05) between producers (22.7 versus 22.5%) and those from VINHAIS producer had a higher (p<0.05) carbohydrate content (14.2 versus 17.8%). The microorganisms evaluated in this work were mesophiles, coliforms, Escherichia coli, Staphylococcus aureus, Clostridium perfringens and Salmonella spp. The alheiras from the producer of BRAGANÇA showed higher counts of mesophiles (6.69 versus 5.45 log ufc/g) and S. aureus (3.34 versus 2.90 log ufc/g) than those of the producer of VINHAIS. The sausages from both producers showed low counts of coliforms, E. coli and C. perfringens. It should also be noted that Salmonella was detected in four out of the 75 analyzed. Throughout the maturation process, the counts of all microorganisms increased gradually. The results of Study 2 evidenced a high variation in the physicochemical parameters studied among the sausages of the different producers, the pH varied between 3.39 and 4.62 and water activity between 0.974 and 0.991. All of the analyzed sausages had mesophiles counts above 6.5 log cfu/g. The principal component analysis identified two components that explained 55.5% of the variation in the 11 original variables. It should be noted that the three pathogenic microorganisms analyzed, Salmonella, S. aureus and C. perfringens were positively correlated with each other, which indicates that poor hygiene conditions and poor manufacturing practices are responsible for the incidence of these pathogenic microorganisms. Artisanally produced alheiras have high variability in physicochemical and microbiological characteristics, which can negatively impact their level of stability and safety. For the valorization of these typical products, appropriate standards of manufacturing process and good hygiene practices should be followed at all stages of production by artisanal producers.
Alheira is a traditional sausage that is linked to the culture and customs of the people of the Trás-os-Montes Portuguese region, whose manufacturing records date back to the 15th century. Currently, the production of alheiras plays an important role in the regional and national economy, so it is very important to study and characterize the physicochemical and microbiological properties to ensure the quality of traditional alheiras. Thus, this work had two main objectives: (i) to study the physicochemical and microbiological characteristics of alheiras throughout the manufacturing process of sausages elaborated by two artisanal producers, one in BRAGANÇA and the other in VINHAIS; and (ii) to construct a quality map, taking into account the physicochemical and microbiological characteristics of artisanally produced alheiras. In order to achieve objective 1 (Study 1), samples were taken, consisting of five sausages from three sampling points, three batches from the VINHAIS producer and two batches from the BRAGANÇA producer. The three sampling points were made on the day of stuffing, in the middle of the maturation process and at the end of the maturation process. For objective 2 (Study 2), a sampling scheme of artisanal sausages produced and marketed in the region of Trás-os-Montes was designed. Five alheiras were acquired from fifteen regional producers, however only the results of six producers are presented in this thesis, since the pandemic COVID-19 prevented us from completing the laboratorial analyses in time for the conclusion of this dissertation. The results of Study 1 revealed that the alheiras from the BRAGANÇA producer had a higher (p<0.05) water activity (0.991 versus 0.985) and moisture content (51.9 versus 48.9%) and lower (p<0.05) pH (5.42 versus 5.54) than that of VINHAIS producer. As expected, during the maturation process, a decrease (p<0.05) in these parameters was observed, so that the minimum values were obtained in the sausages ready for commercialization. On the other hand, in the proximate composition, the alheiras from the producer of BRAGANÇA had higher (p<0.05) contents of crude protein (9.82 versus 9.40%) and ashes (1.47 versus 1.40%) than the alheiras from the VINHAIS producer. The crude fat content did not differ (p>0.05) between producers (22.7 versus 22.5%) and those from VINHAIS producer had a higher (p<0.05) carbohydrate content (14.2 versus 17.8%). The microorganisms evaluated in this work were mesophiles, coliforms, Escherichia coli, Staphylococcus aureus, Clostridium perfringens and Salmonella spp. The alheiras from the producer of BRAGANÇA showed higher counts of mesophiles (6.69 versus 5.45 log ufc/g) and S. aureus (3.34 versus 2.90 log ufc/g) than those of the producer of VINHAIS. The sausages from both producers showed low counts of coliforms, E. coli and C. perfringens. It should also be noted that Salmonella was detected in four out of the 75 analyzed. Throughout the maturation process, the counts of all microorganisms increased gradually. The results of Study 2 evidenced a high variation in the physicochemical parameters studied among the sausages of the different producers, the pH varied between 3.39 and 4.62 and water activity between 0.974 and 0.991. All of the analyzed sausages had mesophiles counts above 6.5 log cfu/g. The principal component analysis identified two components that explained 55.5% of the variation in the 11 original variables. It should be noted that the three pathogenic microorganisms analyzed, Salmonella, S. aureus and C. perfringens were positively correlated with each other, which indicates that poor hygiene conditions and poor manufacturing practices are responsible for the incidence of these pathogenic microorganisms. Artisanally produced alheiras have high variability in physicochemical and microbiological characteristics, which can negatively impact their level of stability and safety. For the valorization of these typical products, appropriate standards of manufacturing process and good hygiene practices should be followed at all stages of production by artisanal producers.
Description
Keywords
Produto cárneo Processamento Patogénicos Composição proximal Análise de componentes principais Mapa de qualidade