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Levedura de Cerveja como agente encapsulante de compostos bioativos de macroalgas: preparação, incorporação num iogurte e caracterização
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Neste trabalho foi avaliada a capacidade da biomassa excedente de levedura do processo cervejeiro (BLC) em ser explorada como material biossorvente de compostos fenólicos e antioxidantes presentes nos extratos das macroalgas: Laminaria digitata (LD), Fucus vesiculosus (FV), Himanthalia elongata (HE) e Eisenia bicyclis (EB). Numa primeira fase foi avaliado o efeito da modificação da parede celular da BLC (alcalinização) na capacidade de biossorção dos compostos de interesse. A biossorção dos compostos bioativos pela BLC foi avaliada por estudos cinéticos e a retenção de compostos fenólicos totais e antioxidantes na BLC foi avaliado por métodos espetrofotométricos. Após 3 horas de ensaio cinético, os resultados sugerem que a BLC alcalinizada apresentou melhor capacidade de biossorção de compostos fenólicos e antioxidantes da macroalga FV e LD, pelo que estes extratos foram os selecionados para a formulação das cápsulas de alginato. Numa segunda fase, foram preparadas diferentes cápsulas de alginato incorporando: (i) BLC (ensaio controlo); (ii) BLC enriquecida nos extratos de macroalga FV e LD – “BLCLD e BLCFV”; (iii) BLC e extratos de macroalga FV e LD - “BLC+LD e BLC+FV”; (iv) BLC enriquecida nos extratos de macroalga FV e LD e BLC e extratos de macroalga FV e LD - “BLCLD+LD e BLCFV+FV”, bem como (v) extratos de macroalga FV e LD – “LD e FV”. Para efeitos comparativos, todas as imobilizações foram realizadas usando a mesma proporção de 1:20 (p/v) de suspensão: 2% (p/v) de alginato de sódio. As cápsulas desenvolvidas foram caracterizadas e incorporadas (1% p/p) na formulação de iogurtes. Os resultados indicaram que as formulações de iogurte contendo as cápsulas enriquecidas (BLCLD e BLCFV) apresentaram um aumento significativo no conteúdo de fenólicos totais (TPC) e na atividade antioxidante (avaliada pelos métodos DPPH, ABTS e FRAP) em comparação com o iogurte controlo e a formulação BLC. A caracterização físico-química das formulações demonstrou que a adição das cápsulas manteve as propriedades essenciais do iogurte (como pH, acidez titulável e sinérese) dentro dos limites aceitáveis para este tipo de produtos, evidenciando a estabilidade da matriz láctea perante o enriquecimento. Desta forma, o estudo valida a eficácia da BLC como um veículo seguro e sustentável para a fortificação funcional de alimentos, permitindo a transferência bem-sucedida dos compostos bioativos das macroalgas para um produto lácteo, e alinhando-se com os princípios da economia circular e do desenvolvimento de nutracêuticos de elevado valor.
This work evaluated the capacity of surplus yeast biomass from the brewing process (BLC) to be explored as a biosorbent material for phenolic compounds and antioxidants present in the subcritical extracts of macroalgae: Laminaria digitata (LD), Fucus vesiculosus (FV), Himanthalia elongata (HE) and Eisenia bicyclis (EB). Firstly, the effect of cell wall modification of BLC (alkalinization) on the biosorption capacity of the target compounds was assessed. Biosorption of the bioactive compounds by BLC was studied through kinetic assays, and the retention of total phenolic compounds and antioxidants in BLC was evaluated using spectrophotometric methods. After 3 hours of kinetic testing, the results suggested that alkalinized BLC showed better biosorption capacity for phenolic and antioxidant compounds from the FV and LD macroalgae extracts; therefore, these extracts were selected for the formulation of alginate capsules. Secondly, different alginate capsules were prepared incorporating: (i) BLC (control assay); (ii) BLC enriched with FV and LD macroalgal extracts – “BLCLD and BLCFV”; (iii) BLC and FV and LD macroalgal extracts – “BLC+LD and BLC+FV”; (iv) BLC enriched with FV and LD macroalgal extracts and BLC combined with FV and LD macroalgal extracts – “BLCLD+LD and BLCFV+FV”; and (v) FV and LD macroalgal extracts alone – “LD and FV”. For comparative purposes, all immobilizations were carried out using the same suspension ratio of 1:20 (w/v): 2% (w/v) sodium alginate. Finally, the developed capsules were characterized and incorporated (1% w/w) into yogurt formulations. The results indicated that yogurt formulations containing the enriched capsules (BLCLD and BLCFV) showed a significant increase in total phenolic content (TPC) and antioxidant activity (evaluated by the DPPH, ABTS, and FRAP methods) compared to the control yogurt and the BLC formulation. The physicochemical characterization of the formulations demonstrated that the addition of the capsules maintained the essential properties of yogurt (such as pH, titratable acidity, and syneresis) within acceptable limits for this type of product, evidencing the stability of the dairy matrix under enrichment. Thus, the study validates the effectiveness of BLC as a safe and sustainable vehicle for the functional fortification of foods, enabling the successful transfer of macroalgal bioactives into a dairy product, while aligning with the principles of circular economy and the development of high-value nutraceuticals.
This work evaluated the capacity of surplus yeast biomass from the brewing process (BLC) to be explored as a biosorbent material for phenolic compounds and antioxidants present in the subcritical extracts of macroalgae: Laminaria digitata (LD), Fucus vesiculosus (FV), Himanthalia elongata (HE) and Eisenia bicyclis (EB). Firstly, the effect of cell wall modification of BLC (alkalinization) on the biosorption capacity of the target compounds was assessed. Biosorption of the bioactive compounds by BLC was studied through kinetic assays, and the retention of total phenolic compounds and antioxidants in BLC was evaluated using spectrophotometric methods. After 3 hours of kinetic testing, the results suggested that alkalinized BLC showed better biosorption capacity for phenolic and antioxidant compounds from the FV and LD macroalgae extracts; therefore, these extracts were selected for the formulation of alginate capsules. Secondly, different alginate capsules were prepared incorporating: (i) BLC (control assay); (ii) BLC enriched with FV and LD macroalgal extracts – “BLCLD and BLCFV”; (iii) BLC and FV and LD macroalgal extracts – “BLC+LD and BLC+FV”; (iv) BLC enriched with FV and LD macroalgal extracts and BLC combined with FV and LD macroalgal extracts – “BLCLD+LD and BLCFV+FV”; and (v) FV and LD macroalgal extracts alone – “LD and FV”. For comparative purposes, all immobilizations were carried out using the same suspension ratio of 1:20 (w/v): 2% (w/v) sodium alginate. Finally, the developed capsules were characterized and incorporated (1% w/w) into yogurt formulations. The results indicated that yogurt formulations containing the enriched capsules (BLCLD and BLCFV) showed a significant increase in total phenolic content (TPC) and antioxidant activity (evaluated by the DPPH, ABTS, and FRAP methods) compared to the control yogurt and the BLC formulation. The physicochemical characterization of the formulations demonstrated that the addition of the capsules maintained the essential properties of yogurt (such as pH, titratable acidity, and syneresis) within acceptable limits for this type of product, evidencing the stability of the dairy matrix under enrichment. Thus, the study validates the effectiveness of BLC as a safe and sustainable vehicle for the functional fortification of foods, enabling the successful transfer of macroalgal bioactives into a dairy product, while aligning with the principles of circular economy and the development of high-value nutraceuticals.
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Laminaria digitata (LD) Fucus vesiculosus (FV) Himanthalia elongata (HE) e Eisenia bicyclis (EB) Biomassa de levedura de cerveja (BLC) Antioxidantes Levedura enriquecida Iogurte