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Valorização integrada de resíduos e subprodutos da extração do azeite: extração e caraterização de compostos bioativos do bagaço de azeitona
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Abstract(s)
Os subprodutos da indústria oleica têm-se revelado como uma das mais promissoras fontes de compostos bioativos, apresentando elevada atividade antioxidante. Contudo, a sua valorização na criação de novos produtos e oportunidades não tem sido devidamente considerada.
Este trabalho consistiu em otimizar um método de extração dos compostos bioativos do bagaço de azeitona, a partir de processos emergentes, entre eles, o micro-ondas e os ultrassons. Foram testados tempos entre 10 a 30 segundos e 5 a 15 minutos para as extrações assistida por micro-ondas e ultrassons, respetivamente e combinações entre eles. A otimização foi efetuada tendo em consideração o teor de compostos fenólicos totais.
Comparativamente com os ultrassons, o micro-ondas foi o processo mais eficiente, obtendo-se um valor de compostos fenólicos totais de 990,5 ± 217,8 mg EAG/100 g de bagaço seco para um tempo máximo de 30 s e na ausência de combinações.
Procedeu-se também ao aumento da escala de produção através de uma panela de evaporação a 100 °C durante 10 minutos, tendo sido determinado o conteúdo em compostos fenólicos totais (69 ± 1,76 mg/100 mL), flavonoides (11 ± 0,22 mg/100 mL) e a capacidade antioxidante (57,4 ± 3,5 mM/100 mL).
Paralelamente procedeu-se ao encapsulamento dos compostos bioativos extraídos através de um material encapsulante (maltodextrina). O material extratado foi ainda aproveitado para substituir parte de farinha de trigo no desenvolvimento de uma nova formulação de pães.
Este trabalho provou que a aplicação de micro-ondas é um método eficiente na extração dos compostos bioativos provenientes do bagaço de azeitona. Os compostos extraídos poderão ser encapsulados e utilizados em diversas aplicações na indústria com vista ao desenvolvimento de produtos de valor acrescentado.
The by-products of the olive oil extraction industry have proved to be one of the most promising sources of bioactive compounds with high antioxidant activity. However, their valorization, by the development of new products and opportunities has not been properly considered. The objective of this work was to optimize a method of extraction of bioactive compounds from olive pomace using emerging technologies, including microwave and ultrasound processes. Different times of processing for microwave and ultrasound, 10 to 30 s and 5 min to 15, respectively and also combinations of those treatments were tested. The optimization was carried out taking into account the content of the total phenolic compounds. The microwave treatment, compared with ultrasound, was the most efficient process, showing values of 990.51 ± 217.77 mg GAE / 100 g of dry pomace when a maximum time of 30 s was applied and in the absence of combinations. A scale-up of the process was also run with an evaporation pan at 100 °C for 10 minutes, and the total phenolic content (1.76 ± 69 mg / 100 mL), flavonoids (11 ± 0 22 mg / 100 ml) and antioxidant activity (57.4 ± 3.5 mM / 100 ml) were determined. In parallel, the extracted bioactive compounds were encapsulated with maltodextrin. The remaining material was further used to replace part of wheat flour in the development of a new formulation of bread rolls. This work proved that the application of microwaves is an efficient method for the extraction of bioactive compounds from olive pomace. The extracted compounds may be encapsulated and used in various applications in the industry to develop products with added-value.
The by-products of the olive oil extraction industry have proved to be one of the most promising sources of bioactive compounds with high antioxidant activity. However, their valorization, by the development of new products and opportunities has not been properly considered. The objective of this work was to optimize a method of extraction of bioactive compounds from olive pomace using emerging technologies, including microwave and ultrasound processes. Different times of processing for microwave and ultrasound, 10 to 30 s and 5 min to 15, respectively and also combinations of those treatments were tested. The optimization was carried out taking into account the content of the total phenolic compounds. The microwave treatment, compared with ultrasound, was the most efficient process, showing values of 990.51 ± 217.77 mg GAE / 100 g of dry pomace when a maximum time of 30 s was applied and in the absence of combinations. A scale-up of the process was also run with an evaporation pan at 100 °C for 10 minutes, and the total phenolic content (1.76 ± 69 mg / 100 mL), flavonoids (11 ± 0 22 mg / 100 ml) and antioxidant activity (57.4 ± 3.5 mM / 100 ml) were determined. In parallel, the extracted bioactive compounds were encapsulated with maltodextrin. The remaining material was further used to replace part of wheat flour in the development of a new formulation of bread rolls. This work proved that the application of microwaves is an efficient method for the extraction of bioactive compounds from olive pomace. The extracted compounds may be encapsulated and used in various applications in the industry to develop products with added-value.
Description
Dissertação de Mestrado, Tecnologia de Alimentos, Instituto Superior de Engenharia, Universidade do Algarve, 2016
Keywords
Bagaço de azeitona Compostos bioativos Atividade antioxidante Micro-ondas Ultrassons Encapsulamento Olive pomace Bioactive compounds Antioxidant activity Microwave Ultrasound Encapsulation Dieta mediterrânica