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Farinha de batata-doce: preservação da bioacessibilidade de fitoquímicos por interação com fibra alimentar
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A batata-doce (Ipomoea batatas (L.) Lam.) é um hortícola de elevado interesse nutricional e funcional, destacando-se pelo conteúdo em fitoquímicos com atividade antioxidante. Contudo, trata-se de uma raiz tuberosa perecível, com dificuldades de conservação pós-colheita. A transformação em farinha surge como estratégia para prolongar a sua utilização e diversificar aplicações alimentares, valorizando esta matéria-prima em contextos industriais. O presente estudo avaliou o efeito da variedade, do pré-tratamento por Campos Elétricos Pulsados (PEF) e da interação com a matriz alimentar (fibra/amido) na composição e bioacessibilidade de antioxidantes em farinha de batata-doce, bem como a sua aplicação como ingrediente funcional. Foram estudadas três variedades: Bonita (polpa branca), Bellevue (polpa alaranjada) e NP-1648 (polpa roxa). As raízes foram desidratadas e processadas em farinhas com e sem pré-tratamento PEF (1,5-3 kV/cm; 200 pulsos) e caracterizadas quanto à composição proximal, perfil bioativo (fenóis, carotenoides, antocianinas, atividade antioxidante) e bioacessibilidade in vitro através do protocolo INFOGEST. Analisou-se ainda a interação dos fitoquímicos com as frações de fibra e amido, e a incorporação da farinha em iogurte natural. A variedade foi o fator mais determinante no perfil bioativo: Bellevue apresentou teores superiores de carotenoides (>60 mg β-caroteno/100 g MS) e NP-1648 maiores níveis de antocianinas (~40 mg C3G/100 g MS). O pré-tratamento por PEF não promoveu benefícios significativos. A fração fibrosa atuou como reservatório de fitoquímicos, modulando a sua libertação na digestão. A aplicação em iogurte mostrou-se viável, com aumento nos teores de fenólicos e carotenoides e aceitabilidade sensorial satisfatória até 8% de incorporação. Conclui-se que a farinha de batata-doce tem elevado potencial como ingrediente funcional sem glúten.
Sweet potato (Ipomoea batatas (L.) Lam.) is a horticultural crop of high nutritional and functional interest, mainly due to its content of phytochemicals with antioxidant activity. However, it is a perishable tuberous root with post-harvest preservation challenges. Converting it into flour is a strategy to extend its utilisation and diversify food applications, adding value to this raw material in industrial contexts. This study evaluated the effect of variety, Pulsed Electric Fields (PEF) pre-treatment, and interaction with the food matrix (fiber/starch) on the composition and bioaccessibility of antioxidants in sweet potato flour, as well as its application as a functional ingredient. Three varieties were studied: Bonita (white flesh), Bellevue (orange flesh), and NP-1648 (purple flesh). The roots were dehydrated and processed into flours with and without PEF pre-treatment (1.5–3 kV/cm; 200 pulses), and characterized for proximal composition, bioactive profile (phenolics, carotenoids, anthocyanins, antioxidant activity), and bioaccessibility using the INFOGEST in vitro gastrointestinal digestion protocol. The interaction of phytochemicals with fiber and starch fractions and flour incorporation in plain yogurt were also analyzed. Variety was the most determining factor in the bioactive profile: Bellevue flour had higher carotenoid content (>60 mg β-carotene/100 g DM), while NP-1648 showed higher anthocyanin levels (~40 mg C3G/100 g DM). PEF pre-treatment, under the applied conditions, did not significantly improve compound retention or bioaccessibility. The fiber fraction acted as the main reservoir of phytochemicals, modulating their release during digestion. Incorporation into yogurt proved feasible, with increased total phenolic and carotenoid contents and acceptable sensory properties up to 8% inclusion. It is concluded that sweet potato flour has high potential as a gluten-free functional ingredient.
Sweet potato (Ipomoea batatas (L.) Lam.) is a horticultural crop of high nutritional and functional interest, mainly due to its content of phytochemicals with antioxidant activity. However, it is a perishable tuberous root with post-harvest preservation challenges. Converting it into flour is a strategy to extend its utilisation and diversify food applications, adding value to this raw material in industrial contexts. This study evaluated the effect of variety, Pulsed Electric Fields (PEF) pre-treatment, and interaction with the food matrix (fiber/starch) on the composition and bioaccessibility of antioxidants in sweet potato flour, as well as its application as a functional ingredient. Three varieties were studied: Bonita (white flesh), Bellevue (orange flesh), and NP-1648 (purple flesh). The roots were dehydrated and processed into flours with and without PEF pre-treatment (1.5–3 kV/cm; 200 pulses), and characterized for proximal composition, bioactive profile (phenolics, carotenoids, anthocyanins, antioxidant activity), and bioaccessibility using the INFOGEST in vitro gastrointestinal digestion protocol. The interaction of phytochemicals with fiber and starch fractions and flour incorporation in plain yogurt were also analyzed. Variety was the most determining factor in the bioactive profile: Bellevue flour had higher carotenoid content (>60 mg β-carotene/100 g DM), while NP-1648 showed higher anthocyanin levels (~40 mg C3G/100 g DM). PEF pre-treatment, under the applied conditions, did not significantly improve compound retention or bioaccessibility. The fiber fraction acted as the main reservoir of phytochemicals, modulating their release during digestion. Incorporation into yogurt proved feasible, with increased total phenolic and carotenoid contents and acceptable sensory properties up to 8% inclusion. It is concluded that sweet potato flour has high potential as a gluten-free functional ingredient.
Descrição
Dissertação de Mestrado, Engenharia Alimentar, 2025, Universidade de Lisboa, Instituto Superior de Agronomia.
Palavras-chave
desidratação pré-tratamentos atividade antioxidante digestão in vitro ingredientes funcionais sem glúten dehydration pre-treatments antioxidant activity in vitro digestion gluten-free functional ingredient