Carotenoid-based solutions for the replacement of artificial colorants in pastry products

• Autor(a) principal: Martins, Pedro Miguel Mota
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10198/24712
• topic: Solanum lycopersicum L.; Ultrasound-assisted extraction; HLPC-DAD-ESI/MS; Carotenoid-rich extracts:Pastry products; Domínio/Área Científica::Ciências Agrárias::Biotecnologia Agrária e Alimentar

Colour has a great importance in the first consumers’ impression, allowing to infer about the overall quality, the taste, the smell, the texture, and even the safety of foodstuff. For these reasons, there is a massive use of colorants in food products. Among the numerous natural matrices potentially used for the extraction of colouring compounds, the fruits from the genus Solanum represent promising sources of pigments, namely carotenoids. This reason, together with the fact that large amounts of fresh tomato wastes (resulting from crop growing, packaging, processing, storage, and sale) are discarded worldwide, make the recovery of valuable colorant biomolecules from agri-food wastes a crucial step of the circular economy by re-introducing them into the food chain as ingredients. In the present work, ultrasound-assisted methodologies were applied to obtain carotenoid-rich colouring extracts from three varieties of tomato (traditional red tomato - Solanum lycopersicum L., cherry tomato – S. lycopersicum var. cerasiforme, and yellow pear tomato – S. lycopersum 'Beam's Yellow Pear), using green solvents, and HLPC-DAD-ESI/MS to establish the carotenoid profile of each sample. Furthermore, the most promising and bioactive extracts were applied in a commercialized pastry cream to substitute the currently used artificial colorants, and finally an in-depth nutritional, chemical, and bioactive characterization of the obtained products was performed, complemented with their physical attributes, studied at Time 0 and 3 days of storage. Lycopene and β-carotene were the major carotenoids found in tomato extracts. None of the studied samples showed hepatotoxicity (including the artificial colorant), and cherry tomato extract was the one with the highest antioxidant and antimicrobial activity. All the creams coloured with the three tomato extracts revealed a uniform aspect and were stable in terms of structure and colour after the heat resistance test. The colour of the creams revealed no significant change over time; however, the pH levels suffered a growing tendency, except for the cream coloured with yellow pear tomato extract, which presented the most stable pH levels. As expected, the cream with the artificial colorant showed the best texture attributes, since the high quantity of carotenoid-rich extracts needed to achieved the final color lead to a weaker texture. Nevertheless, the cream coloured with cherry tomato extract presented the strongest cohesiveness and work of cohesion, while cream with yellow pear tomato presented the best firmness and consistency.Cherry tomato coloured cream presented the highest amounts of protein, fat, and ash, as also higher energetic value. Three soluble sugars were found, fructose, glucose, and trehalose; and citric acid was the major organic acid detected. Saturated fatty acids were found in the highest percentages in all samples, mainly due to the presence of palmitic acid, being oleic acid the second most abundant fatty acid. Finally, all creams revealed antioxidant properties, similar to the respective extracts, and no toxicity was observed for the VERO cell line. A significant improvement in the antimicrobial activity of the creams was verified, comparing with the extract, especially in the cream coloured with cherry tomato extract. The colouring capacity of these molecules makes them a very attractive target for the industrial sector, since carotenoid-based colorants appear as a valid solution for application in the pastry sector, that greatly relies on yellow/orange artificial colorants.