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Abstract(s)
O ergosterol é o esterol maioritário em cogumelos que apresenta diversos efeitos bioativos, nomeadamente atividade antioxidante, anti-inflamatória e antitumoral. Devido à semelhança estrutural com os fitoesteróis, acredita-se que o ergosterol atue de forma idêntica na diminuição dos níveis de colesterol sanguíneo. No entanto, a sua solubilidade limitada, simultaneamente em meio aquoso e em meio lipídico, limita a sua aplicação direta em formulações alimentares. Através de reações de modificação química, nomeadamente acetilação, metilação e esterificação, é possível aumentar a solubilidade desta molécula em meio apolar, o que poderá também resultar num aumento da sua bioatividade e/ou biodisponibilidade. Adicionalmente, uma abordagem interessante para a aplicação do ergosterol ou extratos ricos neste, em formulações maioritariamente aquosas como o iogurte, consiste na sua encapsulação com uma matriz hidrofílica, por exemplo através da técnica de spray drying, o que permitirá maior compatibilidade deste com o alimento em questão, além de preservar as suas propriedades bioativas. Assim, o presente trabalho teve como objetivos: (i) modificar quimicamente o ergosterol visando melhorar a sua compatibilidade com matrizes alimentares lipofílicas e aumentar a sua bioatividade; (ii) encapsular extratos de Agaricus bisporus ricos em micoesteróis, nomeadamente ergosterol, através da técnica de spray drying, tendo-se estudado para o efeito um sistema químico onde a maltodextrina foi reticulada com ácido cítrico. Como último passo, foram desenvolvidas duas aplicações finais: (i) maionese enriquecida com ergosterol modificado quimicamente, tendo-se selecionado para o efeito o composto modificado que apresentou maior bioatividade (ergosterol acetilado); (ii) iogurte enriquecido com micoesteróis onde o efeito da encapsulação foi avaliado em termos da bioatividade do produto final e performance comparativa com o extrato incorporado na forma livre. Os resultados obtidos permitiram avaliar as estratégias aplicadas (modificação química e microencapsulação) como promissoras para suportar o desenvolvimento de alimentos enriquecidos com ergosterol/micoesteróis onde a sua bioatividade é preservada, ou mesmo incrementada.
Ergosterol is a fungal sterol that shows different bioactive effects mainly antioxidant, anti-inflammatory and antitumor activities. Due to the structural similarity with phytosterols, it is believed that ergosterol acts identically in the decrease of blood cholesterol levels. However, its insolubility, both in aqueous and lipid media, limits its direct application in food formulations. Through chemical modification, namely acetylation, methylation and esterification, it is possible to increase the solubility of this molecule in non-polar media, which may also increase its bioactivity and/or bioavailability. Moreover, an interesting approach for the application of ergosterol itself and ergosterol rich extracts in hydrophilic formulations, such as yogurt, is the encapsulation by spray drying, which will allow to increase compatibility with the food matrix, besides preserving its bioactive properties. Thus, the present work had the following objectives: (i) to chemically modify ergosterol in order to improve its compatibility with lipophilic food matrices and to increase its bioactivity; (ii) to encapsulate extracts of Agaricus bisporus rich in mycoesterols, namely ergosterol, through the spray drying technique, where a chemical system based on maltodextrin crosslinked with citric acid was studied. As a final step, two final applications were developed: (i) mayonnaise enriched with chemically modified ergosterol, being selected the modified form having the highest bioactivity among the produced ones (acetylated form); (ii) yoghurt enriched with mycoesterols where the effect of encapsulation was evaluated in terms of the bioactivity of the final product and comparative performance with the yoghurt incorporated with the free form. The results obtained allowed to evaluate the applied strategies (chemical modification and microencapsulation) as promising ones able to support the development of foods enriched with ergosterol/mycoesterols, where bioactivity is preserved, or even increased.
Ergosterol is a fungal sterol that shows different bioactive effects mainly antioxidant, anti-inflammatory and antitumor activities. Due to the structural similarity with phytosterols, it is believed that ergosterol acts identically in the decrease of blood cholesterol levels. However, its insolubility, both in aqueous and lipid media, limits its direct application in food formulations. Through chemical modification, namely acetylation, methylation and esterification, it is possible to increase the solubility of this molecule in non-polar media, which may also increase its bioactivity and/or bioavailability. Moreover, an interesting approach for the application of ergosterol itself and ergosterol rich extracts in hydrophilic formulations, such as yogurt, is the encapsulation by spray drying, which will allow to increase compatibility with the food matrix, besides preserving its bioactive properties. Thus, the present work had the following objectives: (i) to chemically modify ergosterol in order to improve its compatibility with lipophilic food matrices and to increase its bioactivity; (ii) to encapsulate extracts of Agaricus bisporus rich in mycoesterols, namely ergosterol, through the spray drying technique, where a chemical system based on maltodextrin crosslinked with citric acid was studied. As a final step, two final applications were developed: (i) mayonnaise enriched with chemically modified ergosterol, being selected the modified form having the highest bioactivity among the produced ones (acetylated form); (ii) yoghurt enriched with mycoesterols where the effect of encapsulation was evaluated in terms of the bioactivity of the final product and comparative performance with the yoghurt incorporated with the free form. The results obtained allowed to evaluate the applied strategies (chemical modification and microencapsulation) as promising ones able to support the development of foods enriched with ergosterol/mycoesterols, where bioactivity is preserved, or even increased.
Description
Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do Paraná