Development of a new colouring agent from Gomphrena globosa L.: optimization of the extraction process, stability studies and proof-of-concept in a food matrix

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Enhancing the antimicrobial and antifungal activities of a coloring extract agent rich in betacyanins obtained from Gomphrena globosa L. flowers

Publication . Roriz, Custódio Lobo; Barros, Lillian; Prieto Lage, Miguel A.; Ćirić, Ana; Soković, Marina; Morales, Patricia; Ferreira, Isabel C.F.R.

2018Journal article

Open access

Valorisation of black mulberry and grape seeds: Chemical characterization and bioactive potential

Publication . Gómez-Mejía, Esther; Roriz, Custódio Lobo; Heleno, Sandrina A.; Calhelha, Ricardo C.; Dias, Maria Inês; Pinela, José; Rosales-Conrado, Noelia; León-González, María Eugenia; Ferreira, Isabel C.F.R.; Barros, Lillian

Grape (Vitis vinifera L. var. Albariño) and mulberry (Morus nigra L.) seeds pomace were characterized in terms of tocopherols, organic acids, phenolic compounds and bioactive properties. Higher contents of tocopherols (28 ± 1 mg/100 g fw) were obtained in mulberry, whilst grape seeds were richer in organic acids (79 ± 4 mg/100 g fw). The phenolic analysis of hydroethanolic extracts characterised grape seeds by catechin oligomers (36.0 ± 0.3 mg/g) and mulberry seeds by ellagic acid derivatives (3.14 ± 0.02 mg/g). Both exhibited high antimicrobial activity against multiresistant Staphylococcus aureus MIC = 5 mg/mL) and no cytotoxicity against carcinogenic and non-tumour primary liver (PLP) cells. Mulberry seeds revealed the strongest inhibition (p lt 0.05) against thiobarbituric reactive substances (IC50 = 23 ± 2 µg/mL) and oxidative haemolysis (IC50 at 60 min = 46.0 ± 0.8 µg/mL). Both seed by-products could be exploited for the developing of antioxidant-rich ingredients with health benefits for industrial application.

2021Journal article

Open access

Natural colorants in cookies: evaluation of the incorporation effects on the physico-chemical composition

Publication . Roriz, Custódio Lobo; Pereira, Eliana; Heleno, Sandrina A.; Carocho, Márcio; Morales, Patricia; Barros, Lillian; Ferreira, Isabel C.F.R.

In order to respond to the industry’s need for additives of natural origin, the exploration of new natural sources for different compounds has increased. Compounds with dyeing capacity are of great interest because, throughout the industrial processing of foods, they eventually see their initial color compromised.1 Thus, it is necessary to add coloring compounds, preferably of natural origin, to meet the demands of consumers, who are aware of the harmful effects that are attributed to some food additives of artificial origin. The addition of a natural colorant to a particular food has several advantages, besides imparting color, it also enriches the food, due to its intrinsic biological benefits. Betacyanins, for instance, are pigmented compounds that have a powerful pink color, being quite abundant in Gomphrena globosa L. flowers, which have strong coloring ability, in addition to their high antioxidant and chemopreventive effects2. In the present work, betacyanins were obtained from purple-colored flowers of G. globosa by ultrasound assisted extraction (UAE) and were further submitted to stabilization processes. The obtained coloring formulations were incorporated in cookies and the influence of this incorporation in the chemical profile regarding fatty acids (GC-FID), sugars (HPLC-RI) and tocopherols (HPLC-fluorescence) of the cookies were evaluated along a shelf-life of 30 days. Furthermore, the cookies were also analyzed for their physical characteristics through the evaluation of the color using a colorimeter (D65 illuminant), analyzing the L*, a* and b* coordinates, where L* represents lightness, a* represents the redness and b* the yellowness. Texture was analyzed with a TA.XT texturometer, evaluating the effects on the hardness, adhesiveness, springness, cohesiveness, chewiness and resilience over the 30 days. Cookies with a commercial colorant and ones with no colorant were used as control samples. As expected, the natural colorants incorporation caused no significant differences among the chemical analyses of the cookies, as the definition of colorants implies that beyond the color imparting no other parameter of the food should be altered. In terms of the cookie profiles, the most abundant individual fatty acid was palmitic acid (C16:0), followed by oleic (C18:1) and linoleic acid (C18:2) contributing to the major prevalence of the saturated fatty acids (SFA), followed by the monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. Sucrose was the only detected sugar and corresponded to  48.5  2.0 g/100 g dw. Regarding the tocopherols, only three of the four isoforms were detected, namely α-, β-, and δ-tocopherol, being α-tocopherol the most abundant ( 29.2  0.8 mg/100 g dw), followed by δ-tocopherol ( 8.0  0.8 mg/100 g dw), and β-tocopherol ( 2.0  0.2 mg/100 g dw). Regarding the physical parameters, among the prepared formulations, the one stabilized by lyophilization presented a loss of the original color. Comparing the developed formulations with the pink commercial colorant, the natural ones showed a better pink color, since this commercial colorant displays a more reddish color, highlight the potential of the developed formulations as real pink colorants. Concerning the texture profile, no significant differences were verified between the samples over the shelf-life of 30 days, although hardness decreased due to retrogradation. The results demonstrated the strong potential of G. globosa as a promising source of betacyanins with a stable pink colour with high applicability in the food industry.

2019Conference object

Open access

Red pitaya (Hylocereus costaricensis) peel as a source of valuable molecules: extraction optimization to recover natural colouring agents

Publication . Roriz, Custódio Lobo; Heleno, Sandrina A.; Alves, Maria José; Oliveira, Beatriz; Pinela, José; Dias, Maria Inês; Calhelha, Ricardo C.; Morales, Patricia; Ferreira, Isabel C.F.R.; Barros, Lillian

Hylocereus costaricensis peel contains large amounts of betacyanins and can be exploited as a source of natural colorants. This work aimed the chemical characterization and evaluation of bioactive properties of this byproduct and the optimization of the ultrasound-assisted extraction (UAE) of betacyanins using the response surface methodology (RSM). Oxalic and malic acids and traces of fumaric acid were detected, as well as the four tocopherol isoforms, predominantly γ-tocopherol. Four betacyanins were identified and used as response criteria for UAE optimization, namely phyllocactin, isobetanin, isophyllocactin, and betanin. Sample processing at 487 W for 38 min result in the maximum betacyanin content (36 ± 1 mg/g dw). The peel extract inhibit the oxidative haemolysis, with IC50 values of 255 and 381 μg/mL for Δt of 60 and 120 min, respectively, and the growth of pathogenic bacteria, with minimum inhibitory concentrations ranging from 5 to 20 mg/mL. Furthermore, no toxicity was observed for normal cells.

2022Journal article

Open access

Antimicrobial and antifungal activities of a coloring extract rich in betacyanins obtained from the flowers of Gomphrena globosa L

Publication . Roriz, Custódio Lobo; Barros, Lillian; Prieto Lage, Miguel A.; Morales, Patricia; Soković, Marina; Barreiro, M.F.; Ferreira, Isabel C.F.R.

There is a huge diversity of pigments from natural origin that can be exploited as colorants in the food industry. Nonetheless, they can additionally provide several bioactive properties, which represent an added-value for food products. Carotenoids, chlorophylls, anthocyanins and betalains are some of the most studied plant-based pigments. Betalains, can be subdivided according to their chemical structure into betacyanins and betaxanthins [1]. Although less exploited than Beta vulgaris L., Gomphrena globosa L. is an important source of betacyanins [2], with antimicrobial and antifungal activity [3]. Thus, the aim of this study was to obtain a pigmented extract from G. globosa with a high antimicrobial and antifungal activity. This objective was implemented by the application of the response surface methodology (RSM), a robust optimization technique that allows to study jointly the effects of several variables and responses, namely in extraction procedures (in this case ultrasound assisted extraction (UAE)). To evaluate the antimicrobial and antifungal properties, the responses were the minimum inhibitory (MIC), minimum bactericidal (MBC) and minimum fungicidal (MFC) concentrations. The optimized UAE conditions were: 10.8 min, 410.5 W, 57.8% ethanol content (ethanol-water mixtures were used) and 5 g/L as solid-liquid ratio, providing the following responses: 1) antibacterial activity: MIC of ~0.15-0.35 g/L) and MBC of ~0.30-0.65 g/L; and 2) antifungal activity: MIC of ~0.20-0.30 g/L and MFC of ~0.40-0.65 g/L. In conclusion, the obtained results evidenced the potential application of the extracts from G. globosa as sources of betacyanins (natural colorants), but also as important antimicrobial and antifungal agents.

2018Conference object

Open access