Bio-based coloring agents for food applications: a “biorefinery” approach from the bio-waste of blueberry fruits and edible petals

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New coloring strategy for dairy products using anthocyanin extracts from edible flowers

Publication . Pires, Tânia C.S.; Corrêa, Rúbia C.G.; Dias, Maria Inês; Barros, Lillian; Barreira, João C.M.; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.

Among dairy fermented products, yogurt is certainly one of the most popular, being consumed worldwide due to its organoleptic and nutritional properties.1 Nevertheless, some of the yogurts available in the market are prepared with artificial colorants, and the recent concerns with the safety of these compounds push forward the development and application of natural alternatives. Edible flowers, rich in natural pigments, arise as promising sources for the development of new coloring strategies for food products.2 The central aim of the present work focuses on the use of anthocyanin-rich extracts from edible petals of Rosa damascena “Alexandria” and R. gallica “French” draft in R. canina, as an alternative to the E163 (anthocyanin commercial extract) as a new way of coloring dairy products (specifically yogurts). The anthocyanin aqueous extract from rose petals was characterized for its anthocyanin profile by HPLC- DAD-ESI/MS. Furthermore, it was incorporated in natural yogurts and the stability of the developed color was assessed on two distinct periods (preparation day and after 7 days of storage at 4 oC). Likewise, the nutritional composition (AOAC methods), free sugars (HPLC-RI) and fatty acids (GC-FID) profiles were also evaluated in the developed yogurts. For better comparison a negative control (yogurt without any coloring agent) and a positive control (yogurt with the commercial colorant - E163) were prepared and analyzed considering the same parameters. Two anthocyanins were detected in the aqueous extract of rose, but cyanidin-3,5-O-diglucoside was by far the major compound, as it corresponds to 98% (13.19 ± 0.01 μg/g extract) of the identified anthocyanins (the second was cyanidin-3-O-glucoside). In what concerns its incorporation in yogurts, it should be bear in mind that the use of additives on dairy products has to consider the consumers’ acceptability, being therefore highly dependent on its organoleptic and rheological properties. Likewise, it is crucial that new developed products maintain the same nutritional properties as those available in the market. In this study, the yogurts prepared with the anthocyanin extract of rose petals and the negative and positive controls showed similar nutritional composition, free sugars and fatty acids profile throughout the assayed storage period. In conclusion, rose petals represent a potential coloring alternative (in the yellow-orange range) for dairy products without withdrawing the consumers’ acceptance requisites. With the incorporation of these natural extracts for the development of new food products with high added value, a second objective related with the functionalization of the products might also be achieved, potentiating the health benefits to the consumers.

2019Conference object

Open access

Development of new bilberry (Vaccinium myrtillus L.) based snacks: Nutritional, chemical and bioactive features

Publication . Pires, Tânia C.S.; Dias, Maria Inês; Calhelha, Ricardo C.; Alves, Maria José; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.; Barros, Lillian

The sustainable exploitation of fruit and cereal processing is being conducted to produce novel food products with promising nutritional properties and high content in added value compounds. Herein, three bilberry fruit-based snacks supplemented with edible petals and fruits were characterized for their nutritional properties and chemical composition. The phenolic profile, antioxidant, antibacterial and hepatotoxic properties were analyzed. Protein (3–4 g/100 g dw) and carbohydrates (94.3–94.8 g/100 g dw) represented the major macronutrients. The combination of bilberry fruits with edible petals, calendula and rose, improved the nutritional and phytochemical input in organic acids and tocopherols content, respectively. Also, the supplementation with apple and goji fruits provided higher content in phenolic acids and anthocyanins (up to a 9-fold higher concentration, 199.7 µg/g of extract), also resulting in a higher antioxidant and antibacterial activities. The results obtained can contribute for the development of novel sustainable and healthier snacks for the food industry.

2021Journal article

Open access

Phenolic profile and bioativities of the Portuguese apple of the variety "Bravo de Esmolfe”

Publication . Pires, Tânia C.S.; Dias, Maria Inês; Barros, Lillian; Alves, Maria José; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.

2018Conference object

Open access

Phenolic profile, antioxidant and antibacterial properties of Juglans regia L. (walnut) leaves from the Northeast of Portugal

Publication . Vieira, Vanessa; Pereira, Carla; Pires, Tânia C.S.P.; Calhelha, Ricardo C.; Alves, Maria José; Ferreira, Olga; Barros, Lillian; Ferreira, Isabel C.F.R.

Juglans regia L. (walnut tree) is a recognized source of bioactive compounds with potential health benefits. In this work, hydroethanolic extracts of J. regia leaves were obtained by heat assisted extraction from different Portuguese samples in two phenological stages (green and yellow leaves) aiming to assess the impact of seasonal variations. The samples were compared regarding their phenolic composition and bioactivity. Seventeen phenolic compounds were identified by liquid chromatography combined with a diode array detector and electrospray ionization mass spectrometer (LC-DAD-ESI/MS n ): six phenolic acids, ten flavonoids and one tetralone derivative. The green leaves extracts presented a higher amount of total phenolic compounds (29.70 ± 0.03 mg/g extract) compared with the yellow leaves (23.26 ± 0.06 mg/g extract). In particular, yellow samples were richer in flavonoids (17.4 ± 0.2 mg/g extract; mainly quercetin-3-O-glucoside: 3.64 ± 0.01 mg/g extract), while the green ones presented higher phenolic acids content (16.7 ± 0.2 mg/g extract; mainly trans 3-p-coumaroylquinic acid: 6.9 ± 0.5 mg/g extract). Green leaves extract also presented higher antioxidant potential, achieving IC 50 values around 32 ± 2 μg/mL and 26.8 ± 0.2 μg/mL for the oxidative haemolysis inhibition and the thiobarbituric acid reactive substances assays, respectively. Furthermore, only green leaves samples showed anti-inflammatory potential. The cytotoxic evaluations revealed similar anti-proliferative action of both extracts against the tumor cell lines tested. Also, an analogous anti-bacterial potential of the extracts was observed, with preferential action against Gram-positive clinical isolated bacteria, with lower minimum inhibitory concentration (MIC) values for Enterococcus faecalis and Listeria monocytogenes (MIC = 2.5 mg/mL). Therefore, the present study suggests the use of walnut leaves as a source of active ingredients without hepatotoxic effects to be used in different applications in the food or pharmaceutical areas

2019Journal article

Open access

Variedade portuguesa de maçã “Bravo de Esmolfe” como fonte de compostos bioativos com propriedades antioxidantes e antibacterianas

Publication . Pires, Tânia C.S.; Dias, Maria Inês; Barros, Lillian; Alves, Maria José; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.

A maçã Malus domestica Borkh é uma das frutas mais consumidas no mundo. Apresenta uma composição variada e equilibrada, moderadamente energética com teores de açúcares e ácidos que lhes conferem um sabor e uma doçura agradáveis [1]. Esta maçã é um produto com Denominação de Origem Protegida (DOP), sendo grande parte da sua produção restrita à região do interior norte de Portugal [2]. O objetivo do presente trabalho foi determinar as suas propriedades bioativas e o perfil fenólico individual no extrato hidrometanólico por HPLC-DAD-ESI/MS, sendo a identificação realizada através do padrão de fragmentação dos compostos e da comparação com dados obtidos na literatura. A atividade antioxidante dos extratos foi realizada utilizando 3 ensaios distintos: efeito captador de radicais livres - DPPH, inibição da descoloração de β-caroteno e inibição da peroxidação lipídica - TBARS. A atividade antimicrobiana foi testada usando o método de microdiluição e o ensaio colorimétrico de cloreto de p-iodonitrotetrazólio (INT) para determinar a concentração mínima inibitória (MIC). Foram identificados quinze compostos fenólicos, sendo os mais abundantes o ácido 5-O-cafeoilquínico (52 mg/100 g de massa seca), seguido de procianidina B2 (35 mg/100 g de massa seca). Os menores valores de EC50 foram obtidos para os ensaios de efeito captador de radicais livres e inibição da peroxidação lipídica (EC50 = 0,71 e 0,45 mg/mL, respetivamente). Os extratos hidrometanólicos de maçã mostraram ser efetivos contra todas as estirpes de bactérias Gram-positivo testadas, enquanto que para as bactérias Gram-negativo apenas apresentaram atividade para Escherichia coli e Morganella morganii. Estes resultados demonstram que a variedade portuguesa de maçã “Bravo de Esmolfe” pode ser utilizada como fonte de compostos bioativos com propriedades antioxidantes e antibacterianas.

2018Conference object

Open access