OliveAged: The influence of olive tree age on fruit-associated endophytes, bioactivity and quality of olive oil of cv. Verdeal Transmontana

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Application of the FTIR technique as a non‐invasive tool to discriminate Portuguese olive oils with protected designation of origin

Publication . Lamas, Sandra; Ruano, Daniela Filipa Magalhães; Dias, Francisco; Barreiro, M.F.; Pereira, J.A.; Peres, António M.; Rodrigues, Nuno

Three Portuguese olive oils with PDO (‘Azeite do Alentejo Interior’, ‘Azeites da Beira Interior’ and ‘Azeite de Trás-os-Montes’) were studied considering their physicochemical quality, antioxidant capacity, oxidative stability, total phenols content, gustatory sensory sensations and Fourier transform infrared (FTIR) spectra. All oils fulfilled the legal thresholds of EVOOs and the PDO's specifications. Olive oils from ‘Azeite da Beira Interior’ and ‘Azeite de Trás-os-Montes’ showed greater total phenols contents and antioxidant capacities, while ‘Azeites da Beira Interior′ presented higher oxidative stabilities. Linear discriminant models were developed using FTIR spectra (transmittance and the 1st and 2nd derivatives), allowing the correct identification of the oils’ PDO (100 % sensitivity and specificity, repeated K-fold-CV). This study also revealed that multiple linear regression models, based on FTIR transmittance data, could predict the sweet, bitter, and pungent intensities of the PDO oils (R2≥0.979±0.016; RMSE≤0.26±0.05, repeated K-fold-CV). This demonstrates the potential of using FTIR as a non-destructive technique for authenticating oils with PDO.

2024Journal article

Open access

FTIR coupled with chemometrics as a non-invasive tool for PDO olive oils’ discrimination

Publication . Lamas, Sandra; Ruano, Daniela Filipa Magalhães; Rodrigues, Nuno; Barreiro, Filomena; Peres, António M.; Pereira, José Alberto

Quality schemes protect the diversity of traditional European foods, such as the Protected Designation of Origin (PDO) and the Protected Geographical Indication (PGI). Only the olive oils from extra virgin and virgin commercial categories can be labelled with a PDO or PGI. In Portugal, currently, there are six PDOs. Olive oils labelled as PDO present a superior chemical-sensory quality. Therefore, from a commercial point of view it is of paramount importance to be able to identify them according to the correct label, avoiding fraud and ensuring the consumer regarding the exact origin of the purchased oil. Non-invasive and fast techniques, like Fourier transform infrared spectroscopy (FTIR), have been applied to assess olive oil origin and to detect fraud and adulterations. Thus, this work aimed to use FTIR spectra coupled with linear discriminant analysissimulated annealing algorithm (LDA-SA) to classify commercial olive oils belonging to three Portuguese PDOs, namely, ‘Alentejo Interior’, ‘Beira Interior’, and ‘Trás-os-Montes’.

2023Conference poster

Open access

Different approaches to Olive Pomace valorisation

Publication . Cordeiro, Ana; Lamas, Sandra; Rodrigues, Ana; Cadavez, Vasco; Silvério, Sara; Peres, António M.; Rodrigues, Lígia R.; Amorim, Cláudia

Olive pomace (OP) is a substantial by-product, rich in lignocellulosic materials and water, obtained following the extraction of olive oil. It comprises the following components: olive skins, pulp, seeds, and stones. As global olive oil production continues to rise, the management and utilisation of OP have become increasingly important from both an economic and an environmental perspective [1]. In this study, the OP was chemically characterized and its potential as a source of value-added compounds was evaluated. For this purpose, several extraction studies were preformed, namely lipid extraction using petroleum ether, phenolic compound extraction with ethanol, and free sugar extraction with water using a Soxhlet system (Figure 1). These extractions allowed to recover 11.1 ± 0.3 % (w/w) of lipids, different types of phenolic compounds and oligosaccharides. Phenolic compounds are widely recognized for their health-promoting properties (e.g. antioxidant, anti-inflammatory, cancer prevention or antimicrobial activity) and have been the subject of extensive research. Oligosaccharides (OS) are short chains of monosaccharide units linked by glycosidic bonds. The ingestion of these compounds has been demonstrated to confer a multitude of salutary effects, predominantly due to their function as prebiotics and their capacity to regulate gut health and influence overall metabolic processes. Enzymatic hydrolysis was also performed using commercial xylanase from Trichoderma reesei, under optimal conditions (pH 4.5, 40°C, 150 rpm) to evaluate the potential of OP to produce xylo-based oligosaccharides [2]. The hydrolysis process was monitored through Thin Layer Chromatography (TLC), High-Performance Liquid Chromatography (HPLC) using different columns, and the Dinitrosalicylic acid (DNS) method (Figure 2). The results indicated the production of xylo-based oligosaccharides, validating the proposed bioprocess as a viable method for XOS production from OP. This approach not only provides value-added to OP but also aligns with sustainable waste management practices.

2024Conference object

Open access