Browsing by Author "Baptista, Filipa"
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- Exploring the Variability in Phenolic Compounds and Antioxidant Capacity in Olive Oil By-Products: A Path to Sustainable ValorizationPublication . Paié-Ribeiro, Jessica; Baptista, Filipa; Gomes, Maria José Marques; Teixeira, Alfredo; Pinheiro, Victor; Outor-Monteiro, Divanildo; Barros, Ana NovoThe olive oil industry generates large volumes of by-products, creating notable environmental and economic concerns. Among these, olive cake (OC)—a primary by-product of olive oil extraction—stands out due to its high content of bioactive compounds and potential for value-added recycling. This study focused on characterizing six OC samples from the Trás-os-Montes and Alto Douro regions, collected at different processing times and mills. The samples included two derived from pressing (COC), two from two-phase centrifugation (TPOC; one partially pitted and one dehydrated), and two exhausted OC (EOC) samples. Fundamental analyses assessed total phenols, ortho-diphenols, flavonoids, antioxidant capacity, and tannin content. Results revealed significant variation (p < 0.05) in phenolic composition, namely ortho-diphenols and flavonoid levels among the samples. EOC 2 exhibited the highest concentrations (19.61, 21.82, and 20.12 mg CAT/g, respectively), while COC 2 had the lowest (5.08, 5.08, and 2.76 mg GA/g, respectively). This correlated with elevated antioxidant activity in EOC 2, as measured by FRAP, DPPH, and ABTS assays (129.98, 78.00, and 56.65 μmol Trolox/g). In contrast, COC 1 and COC 2 displayed the lowest antioxidant activities (32.61 μmol Trolox/g in FRAP and 17.24 and 18.98 μmol Trolox/g in DPPH). Tannin analysis showed the highest total tannin content in the dehydrated and pitted OC samples (250.31 and 240.89 mg CAT/100 g), with COC 2 showing the lowest (88.17 mg CAT/100 g). Condensed tannin content varied significantly, with EOC 2 presenting the highest level (328.17 mg CAT/100 g) and COC 2 the lowest one (20.56 mg CAT/100 g). Through HPLC-PDA-MS, 22 compounds were identified, with luteolin and verbascoside being particularly prevalent. This in-depth characterization supports the potential valorization of olive by-products, advancing sustainability and promoting a circular economy in the olive oil sector.
- From Waste to Resource: Compositional Analysis of Olive Cake’s Fatty Acids, Nutrients and AntinutrientsPublication . Paié-Ribeiro, Jessica; Baptista, Filipa; Teixeira, José; Guedes, Cristina; Gomes, Maria J.; Teixeira, Alfredo; Barros, Ana Novo; Pinheiro, Victor; Outor-Monteiro, DivanildoThe olive oil industry, recognised for its beneficial products for health and food culture, generates a significant amount of by-products that, if not appropriately managed, can pose considerable environmental challenges. This study examined six olive cakes (OC) from the Trás-os-Montes and Alto Douro regions, collected on different dates and mills: two obtained by pressing (COC), two by centrifugation (TPOC), including one partially pitted and one dehydrated, and two exhausted (EOC), which were subjected to conventional chemical analyses, namely dry matter (DM), organic matter (OM), crude fat (CF), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL) profiling fatty acid (FA) and phosphorus and phytic acid content. The dehydrated TPOC had only 8% moisture content (due to drying), followed by EOC with 10% and COC (65–79%). The CF content was high in COC 1 (14.5% in DM), residual in EOC (1.5%) and intermediate in TPOC (9–10%). CP ranged from 5.3 to 7.3%. Notably, NDF levels were high (>65% in 5 samples; pitted TPOC 57.4%) and very lignified (ADL > 23%). Different FA profiles were observed: COC had the highest monounsaturated (76.36 g/100 g), while EOC had the highest saturated (16.56 g/100 g) and polyunsaturated (14.14 g/100 g). Phosphorus and phytic acid content (g/100 g) of EOC 2, TPOC pitted, TPOC dehydrated, COC 1 and COC 2 showed similar values to each other (mean of 0.12 ± 0.02 and 0.44 ± 0.0, respectively), with EOC 1 having the lowest levels (0.07 ± 0.01 and 0.26 ± 0.04, respectively). These results highlight the potential of OCs, especially dry TPOC, which offers transport, conservation and utilisation benefits.