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Incorporação do extrato de folhas de tramazeira (Sorbus aucuparia) fermentadas no pão
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Este estudo avaliou a incorporação de um extrato fermentado de folhas de tramazeira (Sorbus aucuparia) como ingrediente funcional no pão, visando reforçar valor nutricional, actividade antioxidante e estabilidade microbiológica. As folhas secas de tramazeira revelaram contagens microbianas reduzidas (~3 log UFC mL⁻¹) e teor lipídico de 0,37 %, dominado por ácido palmítico; os índices de aterogenicidade (1,86) e trombogenicidade (0,70) indicaram perfil gordo moderadamente saudável.
A extracção de fitoquímicos foi optimizada por metodologia de superfície de resposta, variando etanol (24–95 %) e pH (0,9–5,1). A condição óptima (60 % etanol, pH 3,0) forneceu 244 mg EAG g⁻¹ de fenóis totais, 67 mg EQ g⁻¹ de flavonoides e capacidade antioxidante de 84 µmol Trolox g⁻¹. Ensaios FRAP e Mfec corroboraram o elevado poder redutor, e o extracto inibiu Bacillus cereus, evidenciando potencial conservante.
A fermentação alcoólica do extracto com Saccharomyces cerevisiae foi delineada experimentalmente. O ensaio ideal (5 g folhas, 0,20 g glicose, 1,4 g NH₄NO₃, 105 mL inóculo) gerou taxa específica de crescimento de 0,15 h⁻¹. O extrato fermentado apresentou 844 mg EAG g⁻¹ de fenóis, 199 mg EQ g⁻¹ de flavonoides e actividade antioxidante de 351 mg eq. Trolox g⁻¹ (DPPH) e 8,8 mg eq. ácido ascórbico g⁻¹ (FRAP).
Produziram-se pães com farinha Barbela: controlo e formulações com 0,5 % e 2,0 % de extrato. Durante 96 h de armazenamento, não houve crescimento de bolores, leveduras nem patogénicos nas amostras enriquecidas, ao contrário do controlo. O valor energético manteve-se estável (~245 kcal 100 g⁻¹) e o teor proteico aumentou, sobretudo com 2,0 %. Perfis de ácidos gordos (palmítico, esteárico, oleico, linoleico, linolénico) não agravaram índices de risco cardiovascular.
A adição do extrato reduziu a luminosidade (L*) e conferiu tom avermelhado, efeito atribuído a pigmentos fenólicos. A textura mostrou endurecimento; contudo, a formulação com 0,5 % preservou maciez próxima do pão fresco. Na prova sensorial, esta formulação obteve melhor aceitação, conciliando funcionalidade e agradabilidade.
Conclui-se que o extrato fermentado de folhas de tramazeira é um aditivo natural promissor, capaz de desenvolver pães mais saudáveis, de rótulo limpo e maior vida útil comparado ao pão controlo, alinhados com as atuais tendências de consumo e com a valorização de recursos silvestres.
This study evaluated the incorporation of a fermented extract of rowan leaves (Sorbus aucuparia) as a functional ingredient in bread, aiming to enhance nutritional value, antioxidant activity and microbiological stability. The dried leaves showed low microbial counts (~3 log CFU mL-¹) and a lipid content of 0.37 %, dominated by palmitic acid; the atherogenicity (1.86) and thrombogenicity (0.70) indices indicated a moderately healthy fat profile. The extraction of phytochemicals was optimized by response surface methodology, varying ethanol (24-95 %) and pH (0.9-5.1). The optimum condition (60 % ethanol, pH 3.0) provided 244 mg EAG g-¹ of total phenols, 67 mg EQ g-¹ of flavonoids and an antioxidant capacity of 84 µmol Trolox g-¹. FRAP and Mfec tests corroborated the high reducing power, and the extract inhibited Bacillus cereus, showing preservative potential. The alcoholic fermentation of the extract with Saccharomyces cerevisiae was experimentally designed. The ideal test (5 g leaves, 0.20 g glucose, 1.4 g NH₄NO₃, 105 mL inoculum) generated a specific growth rate of 0.15 h-¹. The fermented extract showed 844 mg EAG g-¹ of phenols, 199 mg EQ g-¹ of flavonoids and antioxidant activity of 351mg eq. Trolox g-¹ (DPPH) and 8.8 mg eq. ascorbic acid g-¹ (FRAP). Breads were produced with Barbela flour: control and formulations with 0.5% and 2.0% extract. During 96 h of storage, there was no growth of molds, yeasts or pathogens in the enriched samples, unlike the control. The energy value remained stable (~245 kcal 100 g-¹) and the protein content increased, especially with 2.0 %. Fatty acid profiles (palmitic, stearic, oleic, linoleic, linolenic) did not worsen cardiovascular risk indices. The addition of the extract reduced luminosity (L*) and gave a reddish hue, an effect attributed to phenolic pigments. The texture showed hardening; however, the 0.5% formulation preserved softness close to that of fresh bread. In the sensory test, this formulation was better accepted, combining functionality and pleasantness. It can be concluded that the fermented extract of rowan leaves is a promising natural additive, capable of developing healthier breads with a clean label and a longer shelf life, in line with current consumer trends and the valorization of wild resources.
This study evaluated the incorporation of a fermented extract of rowan leaves (Sorbus aucuparia) as a functional ingredient in bread, aiming to enhance nutritional value, antioxidant activity and microbiological stability. The dried leaves showed low microbial counts (~3 log CFU mL-¹) and a lipid content of 0.37 %, dominated by palmitic acid; the atherogenicity (1.86) and thrombogenicity (0.70) indices indicated a moderately healthy fat profile. The extraction of phytochemicals was optimized by response surface methodology, varying ethanol (24-95 %) and pH (0.9-5.1). The optimum condition (60 % ethanol, pH 3.0) provided 244 mg EAG g-¹ of total phenols, 67 mg EQ g-¹ of flavonoids and an antioxidant capacity of 84 µmol Trolox g-¹. FRAP and Mfec tests corroborated the high reducing power, and the extract inhibited Bacillus cereus, showing preservative potential. The alcoholic fermentation of the extract with Saccharomyces cerevisiae was experimentally designed. The ideal test (5 g leaves, 0.20 g glucose, 1.4 g NH₄NO₃, 105 mL inoculum) generated a specific growth rate of 0.15 h-¹. The fermented extract showed 844 mg EAG g-¹ of phenols, 199 mg EQ g-¹ of flavonoids and antioxidant activity of 351mg eq. Trolox g-¹ (DPPH) and 8.8 mg eq. ascorbic acid g-¹ (FRAP). Breads were produced with Barbela flour: control and formulations with 0.5% and 2.0% extract. During 96 h of storage, there was no growth of molds, yeasts or pathogens in the enriched samples, unlike the control. The energy value remained stable (~245 kcal 100 g-¹) and the protein content increased, especially with 2.0 %. Fatty acid profiles (palmitic, stearic, oleic, linoleic, linolenic) did not worsen cardiovascular risk indices. The addition of the extract reduced luminosity (L*) and gave a reddish hue, an effect attributed to phenolic pigments. The texture showed hardening; however, the 0.5% formulation preserved softness close to that of fresh bread. In the sensory test, this formulation was better accepted, combining functionality and pleasantness. It can be concluded that the fermented extract of rowan leaves is a promising natural additive, capable of developing healthier breads with a clean label and a longer shelf life, in line with current consumer trends and the valorization of wild resources.
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Ramazeira Trigo Barbela Pão Extrato hidroetanólico Fermentação Aditivos naturais