Browsing by Author "Alvarenga, Nuno"
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- Clean label approaches in cheese production: where are we?Publication . Fernandes, Jaime; Gomes, Sandra; Reboredo, Fernando H.; Pintado, Manuela E.; Amaral, Olga; Dias, João; Alvarenga, NunoThe Clean Label concept has gained significant traction in the cheese industry due to consumer preferences for minimally processed cheeses free from synthetic additives. This review explores different approaches for applying Clean Label principles to the cheese industry while maintaining food safety, sensory quality, and shelf life. Non-thermal technologies, such as high-pressure processing (HPP), pulsed electric fields (PEF), ultra-violet (UV), and visible light (VL), are among the most promising methods that effectively control microbial growth while preserving the nutritional and functional properties of cheese. Protective cultures, postbiotics, and bacteriophages represent microbiological strategies that are natural alternatives to conventional preservatives. Another efficient approach involves plant extracts, which contribute to microbial control, and enhance cheese functionality and potential health benefits. Edible coatings, either alone or combined with other methods, also show promising applications. Despite these advantages, several challenges persist: higher costs of production and technical limitations, possible shorter shelf-life, and regulatory challenges, such as the absence of standardized Clean Label definitions and compliance complexities. Further research is needed to develop and refine Clean Label formulations, especially regarding bioactive peptides, sustainable packaging, and advanced microbial control techniques. Addressing these challenges will be essential for expanding Clean Label cheese availability while ensuring product quality and maintaining consumer acceptance.
- Impact of LAB from Serpa PDO cheese in cheese models: towards the development of an autochthonous starter culturePublication . Araújo-Rodrigues, Helena; Martins, António P. L.; Tavaria, Freni K.; Dias, João; Santos, Maria Teresa; Alvarenga, Nuno; Pintado, Manuela E.Serpa is a protected designation of origin (PDO) cheese produced with raw ewes’ milk and coagulated with Cynara cardunculus. Legislation does not allow for milk pasteurization and starter culture inoculation. Although natural Serpa’s rich microbiota allows for the development of a unique organoleptic profile, it also suggests high heterogeneity. This raises issues in the final sensory and safety properties, leading to several losses in the sector. A possible solution to overcoming these issues is the development of an autochthonous starter culture. In the present work, some Serpa cheese Lactic acid bacteria (LAB)-isolated microorganisms, previously selected based on their safety, technological and protective performance, were tested in laboratory-scale cheeses. Their acidification, proteolysis (protein and peptide profile, nitrogen fractions, free amino acids (FAA)), and volatiles generation (volatile fatty acids (VFA) and esters) potential was investigated. Significant differences were found in all parameters analyzed, showing a considerable strain effect. Successive statistical analyses were performed to compare cheese models and Serpa PDO cheese. The strains L. plantarum PL1 and PL2 and the PL1 and L. paracasei PC mix were selected as the most promising, resulting in a closer lipolytic and proteolytic profile of Serpa PDO cheese. In future work, these inocula will be produced at a pilot scale and tested at the cheese level to validate their application.
- A review on microbiological and technological aspects of Serpa PDO cheese: an ovine raw milk cheesePublication . Araújo-Rodrigues, Helena; Tavaria, Freni K.; Santos, Maria Teresa P. G. dos; Alvarenga, Nuno; Pintado, Maria M.Serpa is a PDO cheese considered one of most popular and relevant traditional Portuguese cheeses due to its unique aroma and flavour, which are very much-appreciated characteristics. The special and recognised sensorial attributes of Serpa cheese are a result of the ingredients used, coupled with the manufacturing process, specifically raw ovine milk and extracts of Cynara cardunculus L. as coagulant, without addition of any starter culture or milk pasteurisation. Serpa quality and safety issues, linked to the high susceptibility and heterogeneity of its final sensorial attributes fosters the importance of large-scale studies focused on biochemical and microbial aspects. Despite the scientific relevance of this traditional product, Serpa studies are still very scarce and limited with the cheesemaking procedure lacking in regulation. Accordingly, the present work emphasises the current knowledge on Serpa PDO cheese, giving an overview and critical analysis of existing studies and discussing Serpa technological process.
- Serpa PDO cheese: towards identification of chemical markers involved in organoleptic attributesPublication . Araújo-Rodrigues, Helena; Tavaria, Freni K.; Santos, Maria Teresa P.G. Dos; Alvarenga, Nuno; Pintado, Manuela M.
- Serpa PDO cheese: towards identification of chemical markers involved in organoleptic attributesPublication . Araújo-Rodrigues, Helena; Tavaria, Freni K.; Santos, Maria Teresa P. G. Dos; Alvarenga, Nuno; Pintado, Manuela M.Serpa is a PDO cheese manufactured using raw ovine milk and extracts of C. cardunculus L. as rennet, without addition of starter cultures and followed by a minimum (but safe) ripening period. Both the processing technology and ingredients used result in a high microbial biodiversity that allows the development of a unique flavor. Variations in the manufacture process and distinct milk composition among producers result in a considerably heterogeneous cheese. The present study aimed at screening some groups of sensorial related compounds during two consecutive months of production, towards the identification of chemical markers involved in the specificity of Serpa cheese. The results suggested a high diversity and heterogenous chemical composition according to the producer and month. The free amino acids (FAAs) profile suggested the presence of almost all amino acids in the analyzed cheeses, being glutamic acid, alanine, leucine, valine and phenylalanine the most prevalent ones. Regarding the organic acid profile, lactic and acetic acids were the dominant groups. The volatile analysis suggested a high diversity and variability of volatile composition between cheeses, including several chemical groups, namely, ethyl esters, aldehydes and alcohols. The identification of sensorial chemical markers will be crucial to guide the selection and development of an autochthonous starter culture to improve Serpa’s quality and safety.
- Technological and protective performance of LAB isolated from Serpa PDO cheese: towards selection and development of an autochthonous starter culturePublication . Araújo-Rodrigues, Helena; Santos, Maria Teresa P. G. dos; Ruiz-Moyano, Santiago; Tavaria, Freni K.; Martins, António P. L.; Alvarenga, Nuno; Pintado, Manuela E.Serpa is an ovine raw milk cheese widely appreciated by the consumers. However, raw milk products may be seen with reservations in terms of safety or technological defects. To overcome that, the addition of an autochthonous starter culture may ensure the cheesemaking process optimization and microbiota dominance. In this work, the technological and protective performance of eleven lactic acid bacteria strains, isolated from Serpa Protected Designation of Origin cheese and reported as generally recognized as safe, were screened. The integration of technological and protective properties studied in the PCA plot, coupled with the proteolytic and lipolytic analysis suggested that Lb. plantarum PL1 and PL4 strains may be the best candidates. These strains showed both proteolytic and lipolytic activities, a good acidification potential, low D-lactic acid production and were well adapted to the salt and temperatures used. PL1 strain also exhibited a higher antimicrobial effect against the pathogenic bacteria studied. Although Lb. paracasei strain showed lower acidification capacity, due to their technological and protective properties, it could be combined with other more acidifying strains. As future work, it is important to establish cheese model systems to complement this screening and implement an autochthonous starter culture.