Fruit residues as alternative sources of red-violet-blue colouring agents for food industry application: from waste to foodstuff attractiveness optimized pathway

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Bioactivities, chemical composition and nutritional value of Cynara cardunculus L. seeds

Publication . Petropoulos, Spyridon Α.; Fernandes, Ângela; Pereira, Carla; Tzortzakis, Nikos; Vaz, Josiana A.; Soković, Marina; Barros, Lillian; Ferreira, Isabel C.F.R.

In the present study, the nutritional value, bioactive properties, and chemical composition of various cardoon (Cynara cardunculus L.) genotypes cultivated in central Greece were investigated. The results demonstrated that Cynara seeds are a good source of fat and protein, while they also contain considerable amounts of K, Mg, and Fe and low amount of Na. Sucrose, oxalic acid, and α-tocopherol were the only free sugar, organic acid, and tocopherol isoform respectively, found among the studied genotypes. The most abundant fatty acids were linoleic, oleic and palmitic acid, while PUFA was the most abundant fatty acid class. All the tested seeds contained only two phenolic compounds, namely 5-O-caffeoylquinic acid and 3,5-O-caffeoylquinic acid, while significant antioxidant activities and cytotoxicity against tumor cell lines and antimicrobial effects were also observed. In conclusion, cardoon seed extracts could be exploited in the food and pharmaceutical industries as alternative sources of natural compounds with bioactive properties.

2019Journal article

Open access

Development of a natural anthocyanin-based food colorant obtained from the fruit epicarp of Prunus spinosa L.

Publication . Leichtweis, Maria Gabriela; Pereira, Carla; Prieto Lage, Miguel A.; Barreiro, M.F.; Baraldi, Ilton J.; Barros, Lillian; Ferreira, Isabel C.F.R.

Prunus spinosa L. is a wild shrub with bitter and astringent fruits with poor commercial value. Nevertheless, they are rich sources of anthocyanins, more specifically cyanidin 3-rutinoside and peonidin 3-rutinoside, which are concentrated in the epicarp. These compounds possess recognized colouring properties and have been increasingly explored for substitution of artificial colorants, for being safer alternatives. In this context, the present work aimed to develop an anthocyanin-based food colorant obtained from P. spinosa fruit epicarp. The conditions that maximize the extraction were optimized, comparing heat (HAE) and ultrasound (UAE) assisted extraction techniques. For that purpose, a response surface methodology was applied, using a circumscribed central composite design with three variables and five levels, being the relevant variables time, temperature (HAE) or power (UAE), and ethanol concentration. The anthocyanin compounds were quantified by HPLC-DAD-ESI/MS. Furthermore, the bioactivity of the optimal extract was assessed through antioxidant, antimicrobial, and cytotoxic activity assays. UAE was the most efficient method, under optimal conditions of 5.0 ± 0.2 min, 400 ± 32 W, and 48 ± 3% ethanol, where the extraction yield was 68.60 ± 2.1%, with a total anthocyanin content of 18 ± 2 mg/g (dried extracted residue-basis) and 11,8 ± 0,8 mg/g (dried epicarp-basis). Additionally, these response values were slightly improved when the solid-to-liquid ratio effect at the optimal conditions in a dose-response format was tested, showing a steady decreasing pattern in the range of 5 to 250 g/L. Regarding bioactive properties, the obtained extract presented antioxidant activity, with EC50 values of 204.22 ± 0.02 μg/mL for the TBARS assay and 296 ± 4 and 509 ± 3 μg/mL for OxHLIA method at 60 and 120 min of reaction, respectively; and antimicrobial properties, allowing the growth inhibition of 9 bacteria strains of public health interest in concentrations from 2.5 to 20 mg/mL. Besides, the obtained extract did not show hepatotoxic effects on a porcine liver primary cell culture (PLP2), being thus safe for incorporation into foodstuff. Lastly, the anthocyanin-based extract was introduced in a traditional Brazilian confectionary product, “beijinho”, where its colouring capacity was confirmed.

2018Conference object

Open access

Arbutus unedo L. as an alternative source of anthocyanin compounds for application as food colouring agent

Publication . Pereira, Carla; López, Cecilia J.; Antonio, Amilcar L.; Prieto Lage, Miguel A.; Barreiro, M.F.; Barros, Lillian; Ferreira, Isabel C.F.R.

Arbutus unedo L., commonly known as strawberry-tree, is a shrub used as ornamental plant in the gloomy Mediterranean areas which fruits are popularly eaten and used to produce beverages . Beyond these common applications, these fruits could also be explored for their phenolic composition, once they are a source of anthocyanin compounds with great colouring capacity to be potentially used in food industry, in detriment of artificial colorants. In this context, the present study aimed to optimize the extraction of these compounds from A. unedo fruits through different techniques, namely heat and ultrasound assisted extraction and, for that purpose, a response surface methodology was applied using the circumscribed central composite design of three variables with five levels. For the model application, the anthocyanin concentration and the extraction yield were used as responses, being the identification of these compounds performed by HPLC-DAD-ESI/MS. The anthocyanin profile of A. unedo fruits consisted of delphinidin-3-glucoside, cyanidin-3-glucoside, and cyanidin-3-pentoside, with cyanidin-3-glucoside as the most abundant one. Heat assisted extraction proved to be the most effective technique at 5 min, 90°C, and 80% of ethanol, yielding 51.2% of fruit dry weight, with a total anthocyanin concentration of 382.4 μg/g of dried fruit, and 744.6 μg/g of extract. Moreover, these response values were slightly improved by studying the solid/liquid ratio effect at the optimal conditions indose-response format, showing steady extraction values from 5 to 40 g/L. The obtained results showed the possibility of using A. unedo fruits as a source of anthocyanin compounds for industrial applications.

2018Conference object

Open access

Citrus hystrix L. condimentary leaves: proximate composition, fatty acids and sugars profile

Publication . Pereira, Carla; Carvalho, Idalina; Barros, Lillian; Ferreira, Isabel C.F.R.

Citrus hystrix L., commonly known as kaffir lime, is a plant belonging to the citrus family (Rutaceae). It is native to South Ásia and Southeast Ásia, mostly occurring in Indonésia, Malaysia, the Philippines, Laos, Thailand, and Vietnam. Its leaves and fruit have been widely used for culinary and traditional medicine purposes. Contrarily to the fruit juice and pulp, which present a pungent taste and therefore are not directly consumed, the leaves are considered as the most important spice in these regions, being added to almost every dish, besides ginger and lemon grass [1,2]. Thus, given the wide application of kafiir lime leaves as condiment, the present study intended to assess its nutritional value, namely its proximate composition in carbohydrates, protein, ash, and fat, as well as its fatty acids and sugars profile by GC-FID and HPLCRI, respectively. Regarding the nutritional composition of the condimentary leaves, carbohydrates were the most abundant macronutrients (64. 7±0.2 g/100 g), followed by protein (17. 98±0.03 g/100 g), and ash (12. 96±0.06 g/100 g). In what concerns fatty acids, twenty-two compounds were detected, among which polyunsaturated fatty acids were prevalent (71. 5±0. 1%), with considerable percentages of linolenic (55. 6±0.2%) and linoleic (15.02±0.07%) acids. This spice alsopresentedpalmitic (15. 1±0.2%) and stearic (3. 6±0.2%) acids as the most abundant saturated fatty acids (26. 29±0. 05%); and oleic (1.243±0.003%) and palmitoleic (0.74±0.05%) acids as the main monounsaturated fatty acids (2. 05±0. 05%). In terms offree sugars, three molecules were identified, with sucrose (3. 5±0. 1 g/100 g) being detected in higher concentrations than fructose and glucose (0. 98±0.04 and 0. 72±0.03 g/100 g, respecüvely). Through the results obtained in the present study, it was possible to verify that kaíËr lime presents an equilibrated nutritional profile, which valorizes its use as condiment, beyond its só appreciated taste.

2018Conference object

Open access

Dehydration process influences the phenolic profile, antioxidant and antimicrobial properties of Galium aparine L.

Publication . Senio, Sylwia; Pereira, Carla; Vaz, Josiana A.; Soković, Marina; Barros, Lillian; Ferreira, Isabel C.F.R.

Galium aparine L. is a very disseminated plant in temperate zones, commonly known as clivers or bedstraw, belonging to the Rubiaceae family and it is traditionally used for its medicinal applications. In this study, G. aparine hydromethanolic extracts and infusions were prepared from air-dried and freeze-dried samples in order to assess their phenolic profile, antioxidant, antimicrobial, and cytotoxic properties. All the studied extracts revealed a similar phenolic profile, but the hydromethanolic extract obtained from the freeze-dried sample presented the highest concentration of phenolic compounds, followed by the respective infusion and the airdried sample hydromethanolic extract. The major compound detected in the extracts was 5-O-caffeoylquinic acid (from 145 to 163 mg/g extract). Regarding the bioactivity, in general, the extracts presenting higher phenolic concentrations also revealed enhanced bioactive properties. The EC50 values obtained in the antioxidant activity assays ranged from 13.5 to 884 μg/mL, with the freeze-dried sample hydromethanolic extract presenting the highest activity (13.5–555 μg/mL). Similar conclusions could be made in terms of antimicrobial properties, with this extract showing the lowest MIC (1.85–15 mg/mL), MBC (3.75–7.5 mg/mL), and MFC (3.75–20 mg/mL) values. None of the extracts revealed cytotoxicity. The results obtained in this study suggested that G. aparine extracts can be a good source of phenolic compounds with antioxidant and antimicrobial properties.

2018Journal article

Open access