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Energy Footprint of Cheese
Publication . Silvério, Karina S.; Freitas, Daniela; Dias, João M.; DCT - Departamento de Ciências da Terra; GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; MDPI - Multidisciplinary Digital Publishing Institute
Cheese production is an ancient practice that is associated with the food and cultural identity of different peoples. There are over 500 cheese types globally, including 207 with protected denomination of origin (PDO) and 70 with protected geographical indication (PGI) status in the European Union (EU). Each cheese has various biochemical compositions, production methods, and maturation environments. This study has provided a critical review of the environmental impacts of cheese production, focusing on energy consumption, greenhouse gas (GHG) emissions, and the integration of renewable energy sources as sustainable strategies for this sector. Based on case studies and life cycle assessment (LCA) methodologies, the analysis revealed significant variability in energy use (3.0 to 70.2 MJ/kg) and GHG emissions (up to 22.13 kg CO2 eq/kg), influenced by factors such as the cheese type, production complexity, system boundaries, and the technological or geographical context. Particular attention was given to heat treatment, refrigeration, and maturation processes, which contribute substantially to the overall energy footprint. The paper also discusses the methodological challenges in LCA studies, including the role of co-product allocation and database limitations. Finally, strategic renewable energy options, such as biogas recovery and solar thermal integration, are discussed as sustainable alternatives to reduce the environmental footprint of the dairy sector and support its sustainability.
Analytical Approaches for the Quality and Food Safety assessment of Olive Oil: Volatile Organic Compounds profiles, Antioxidants and Phthalates content monitoring
Publication . Freitas, Flávia Sofia Salgado de; Silva, Marco; Cabrita, Maria João
In the plant kingdom, many fruits and seeds provide edible oils. However, olive oil,
often referred to as "liquid gold," is the most important and widely used in the Mediterranean
diet. Its nutritional value is considered to be twice that of cereals and ten times greater than
that of wine. It is estimated that approximately 3 million tons of olive oil are consumed worldwide every year.
This doctoral thesis focused on the study of olive oil, addressing three main themes
aimed at deepening the understanding of this food matrix, from its chemical composition to
the factors affecting its quality and safety.
The first theme investigated the evolution of volatile organic compounds throughout
the shelf life of olive oil, focusing on markers associated with positive attributes and sensory
defects. A robust method was developed using solid-phase microextraction in headspace
mode (HS-SPME), coupled with gas chromatography and mass spectrometry (GC/MS). This
method allowed the identification of significant variations in the levels of volatile organic compounds (VOCs), particularly those derived from the lipoxygenase (LOX) pathway, over time.
Principal component analysis (PCA) revealed a clear distinction between the volatile profiles of
extra virgin olive oils and deteriorated oils. The relationship between
E-2-hexenal and acetic
acid proved to be a potential indicator for predicting the sensory disqualification of olive oil
based on the evolution of volatile compounds during storage.
The second theme explored the potential of olive oil as a nutraceutical product, em-
phasizing the antioxidants hydroxytyrosol and tyrosol, both recognized for their health-promoting properties. A method was developed to efficiently extract these compounds from the
by-products of olive oil production. These compounds were concentrated and added to the
final olive oil, resulting in enriched olive oil and a concentrated antioxidant extract with functional applications.The third theme focused on the presence of plasticizers in olive oil, aiming to identify
and quantify phthalate esters. Through a critical review, various analytical methods used for
quantifying phthalates in olive oils and wines were evaluated, discussing analytical challenges
and mitigation strategies. Additionally, a study was conducted to monitor contamination by
plasticizers, including 23 phthalates and 9 phthalate substitutes, throughout the olive oil production and storage process. Using liquid-liquid extraction with hexane/methanol and analysis
by gas chromatography coupled with tandem mass spectrometry (GC-MS/MS), with detection
limits ranging from 0.001 to 0.103 mg/kg, it was observed that plasticizer levels progressively
increased as olive oil went through production stages. The main sources of contamination were
identified, highlighting the importance of minimizing plastic use along the production line and
during storage. Diisononyl phthalate (DINP) was the most prevalent compound, found at concentrations exceeding the migration limits established by the European Union in some olive
oils.
The results presented in this thesis contribute to a deeper understanding of the quality,
safety, and functional potential of olive oil, offering practical solutions to optimize its production and preservation, as well as promoting its valorization as a high-value-added food product.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso de avaliação no âmbito do Programa Plurianual de Financiamento de Unidades de I&D (2017/2018) - Financiamento Base
Número da atribuição
UIDB/05183/2020