Associated Laboratory for Green Chemistry - Clean Technologies and Processes

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Publications

Effect of olive leaf incorporation during the industrial extraction of cv. Arbequina Olive oils on their quality and bioactive composition

Publication . Marx, Ítala; Rodrigues, Nuno; Veloso, Ana C.A.; Cruz, Rebeca; Casal, Susana; Pereira, J.A.; Peres, António M.

Extra virgin olive oil (EVOO) is a key element of the Mediterranean diet and is highly appreciated due to its unique nutritional and organoleptic attributes. The documented health-promoting properties of EVOO are associated with several chemical families, with a particular relevance to the phenolic composition, namely to phenolic alcohols and secoiridoid derivatives. This fact has been recognized by the European Food Safety Authority leading to a health claim regarding the protective effect of polyphenols from olive oils against the oxidative stress of blood lipids. In this sense, olive oil industry seeks to uncover technological processes that would ensure increasing the phenolic content of olive oils and thus, to fulfill the health claim requirements. Therefore, this study focused on evaluating the effect of cv. Arbequina leaves addition (1%, w/w) during the industrial extraction of cv. Arbequina oils on their physicochemical-sensory quality, chlorophyll and carotenoids total contents, CIELAB color intensities and individual phenolic profile. It was observed that, leaves incorporation reduced the primary oxidation (peroxide value by 33% and K232 by 17%) and increased the oxidative stability (19%). Moreover, oils amendment promoted the rise of the total phenolic content (up to 293±9 mg GAE/kg), which became richer in secoiridoid derivatives (up to 144±3.0 mg/kg), namely on oleacein content (up to 55±2 mg/kg), as well as in total carotenoids (up to 2.85±0.04 mg lutein equivalents/kg). Furthermore, the addition of Arbequina leaves was able to increase the contents of secoiridoid derivatives after acid hydrolysis, in comparison with oils extracted without leaves, allowing supporting the health claim (5.2±0.2 mg/20 g). Regarding the sensory attributes, the leaves incorporation during extraction enhanced the bitterness (2.9±0.5) and sweetness (7.0±0.4) but decreased the pungency (1.6±0.4). Although the cv. Arbequina leaf incorporation during oils’ extraction increased the potential positive health impact, oils extracted from olives and leaves should not the commercialized as EVOO, according to the European Union regulations.

2021Conference object

Open access

Authentication of Argan (Argania spinosa L.) oil using novel DNA-based approaches: detection of olive and soybean oils as potential adulterants

Publication . Amaral, Joana S.; Raja, Fatima Zahra; Costa, Joana; Grazina, Liliana; Villa, Caterina; Charrouf, Zoubida; Mafra, Isabel

Argan oil is a traditional product obtained from the fruits of the argan tree (Argania spinosa L.), which is endemic only to Morocco. It is commercialized worldwide as cosmetic and food-grade argan oil, attaining very high prices in the international market. Therefore, argan oil is very prone to adulteration with cheaper vegetable oils. The present work aims at developing novel real-time PCR approaches to detect olive and soybean oils as potential adulterants, as well as ascertain the presence of argan oil. The ITS region, matK and lectin genes were the targeted markers, allowing to detect argan, olive and soybean DNA down to 0.01 pg, 0.1 pg and 3.2 pg, respectively, with real-time PCR. Moreover, to propose practical quantitative methods, two calibrant models were developed using the normalized ΔCq method to estimate potential adulterations of argan oil with olive or soybean oils. The results allowed for the detection and quantification of olive and soybean oils within 50–1% and 25–1%, respectively, both in argan oil. Both approaches provided acceptable performance parameters and accurate determinations, as proven by their applicability to blind mixtures. Herein, new qualitative and quantitative PCR assays are proposed for the first time as reliable and high-throughput tools to authenticate and valorize argan oil.

2022Journal article

Open access

Impact of incorporating olive leaves during the industrial extraction of cv. Arbequina oils on the physicochemical–sensory quality and health claim fulfillment

Publication . Marx, Ítala; Casal, Susana; Rodrigues, Nuno; Cruz, Rebeca; Veloso, Ana C.A.; Pereira, J.A.; Peres, António M.

The effect of olive leaves addition (1%, w/w, cvs. Arbequina or Santulhana), during the industrial extraction of Arbequina oils, on their physicochemical, color, phenolic profile, and sensory characteristics, was studied. Leaves’ incorporation reduced the primary oxidation (peroxide value by 33% and K232 by 17%) and increased the oxidative stability (19%), with the impact being more pronounced for Arbequina leaves. For these latter oils, leaves incorporation increased the total phenolic content (293 ± 9 mg GAE/kg), which became richer in secoiridoid derivatives (143.7 ± 3.0 mg/kg). Also, only Arbequina oils extracted with their own leaves supported the health claim regarding the protection of blood lipids against oxidative stress (hydroxytyrosol and tyrosol derivatives content greater than 5 mg per 20 g of olive oil). On the other hand, the incorporation of leaves from cvs. Arbequina and Santulhana during extraction enhanced the bitterness (55–59%) and decreased the pungency (25–33%). Santulhana leaves promoted an increase of the green-fruitiness (5.3 ± 0.5), while Arbequina leaves enhanced the oils’ sweetness (7.0 ± 0.4). Moreover, a potentiometric laboratory-made electronic tongue was applied, as a taste sensor device, being capable of successfully discriminating Arbequina oils extracted without or with addition of leaves, allowing the identification of (un)deliberated leaves incorporation during oils’ extraction. Lastly, it was found that the quality and composition of Arbequina oils industrially extracted were leaf cultivar dependent, with the low level of phenolics of control oils promoted by the incorporation of Arbequina leaves. Graphic abstract: [Figure not available: see fulltext.]

2021Journal article

Open access

Uso sustentável da abóbora: extratos de subprodutos de abóbora egípcia como conservantes natural

Publication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pereira, Carla; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Mohamed, Mustafa H.M.; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, Lillian

Atualmente, a indústria alimentícia tem desenvolvido cada vez mais produtos práticos, prontos para consumo e com longa vida útil.

2023Conference poster

Open access

Effect of different liquid medium on canned tuna

Publication . Ferreiro, Nuno Manuel; Ramalhosa, Elsa; Fernandes, Conceição; Rodrigues, Nuno

Olive oil and fish are two products with a great tradition in Portugal and high importance in the Mediterranean Diet. The beneficial properties of these foods for health, associated with their sensory characteristics, make them highly appreciated by consumers. Virgin olive oil is a vegetable oil rich in monounsaturated fatty acids with unique organoleptic properties that distinguish it from other edible oils. According to the intensity of fruitiness, extra virgin oils can be classified as ripe fruity and green fruity, and the latter as mild, medium and intense, depending on the intensity of the fruitiness. In turn, fish is a source of protein and, depending on the species, of unsaturated fat. The combination of these two nutritionally rich foods results in a product with excellent nutritional and sensory qualities, meeting the constant need for innovation in the industry

2021Conference object

Open access