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Abstract(s)
A indústria vinícola é uma das mais importantes atividades económicas em Portugal. O
principal objetivo deste trabalho consiste na caracterização e incorporação dos subprodutos da
produção de vinho na indústria alimentar como fonte de compostos bioativos. Para isso,
amostras de mosto, engaço e bagaço de duas castas diferentes, Tinta Miúda e Cerceal Branco,
foram sujeitas a diferentes técnicas de extração (convencional, assistida por micro-ondas,
assistida por ultrassons e subcrítica com água a 100, 150 e 200ºC). Para avaliar a eficiência das
técnicas de extração aplicadas, os extratos foram caracterizados tendo-se determinado os teores
de fenólicos (TPC) e taninos totais (TTC), bem como a atividade antioxidante pelos métodos
de ABTS e FRAP.
Das diferentes técnicas de extração testadas, verificou-se que os extratos obtidos por
UAE apresentaram resultados menos favoráveis para a atividade antioxidante. Por outro lado,
os extratos obtidos por extração subcrítica a 150ºC para os engaços e bagaços e a 200ºC para
os mostos apresentaram resultados mais promissores, destacando-se a amostra de engaço
Cerceal Branco com o TPC (17,0 ± 0,2 mg GAE/g fw) e atividade antioxidante (19,9 ± 0,3 e
13,0 ± 0,3 mg AAE/g fw, para os métodos ABTS e FRAP, respetivamente) mais elevados. Nos
6 extratos mais promissores determinou-se o pH, o teor de açúcares totais e o perfil fenólico
por HPLC-DAD, verificando-se que estes extratos eram principalmente constituídos pelos
ácidos neoclorogénico e clorogénico, catequina, epicatequina e a cafeína.
Posteriormente, os 6 extratos previamente selecionados foram incorporados em gomas,
cuja formulação final foi também otimizada (8 g de agar, um rácio de 95:300 mL de água:sumo
de laranja, um rácio de formulação:extrato de 50:5 mL e 30 g de xarope de alfarroba como
adoçante). As gomas produzidas foram caracterizadas tendo-se avaliado o TPC, TTC,
flavonoides totais, atividade antioxidante pelos métodos ABTS, FRAP e DPPH, proteínas
solúveis, açúcares totais, pH e produtos de reação de Maillard. Os resultados obtidos foram
pouco concordantes, e por isso, não foi possível determinar qual a goma produzida que
apresentava características mais promissoras para comercialização. Em relação às
características sensoriais das gomas, também não se obteve a consistência desejada e o seu
tempo de vida útil também é muito curto. Futuramente, ainda é necessário otimizar alguns
parâmetros da receita de gomas, tais como o uso de um agente estabilizante e a quantidade de
extrato a adicionar, de forma a melhorar as propriedades sensoriais e funcionais das gomas.
The wine industry is one of the most important economic activities in Portugal. The main goal of this work is the characterization and incorporation of the by-products of wine production in the food industry as a source of bioactive compounds. For this, samples of must, stem and bagasse from two different grape varieties, Tinta Miúda and Cerceal Branco, were subjected to different extraction techniques (conventional, microwave-assisted, ultrasound assisted and subcritical with water at 100, 150 and 200ºC). To evaluate the efficiency of the applied extraction techniques, the extracts were characterized by determining the total phenolic (TPC) and total tannins (TTC) contents, as well as the antioxidant activity by the ABTS and FRAP methods. From the different extraction techniques tested it was found that the obtained extracts by UAE presented less favorable results for antioxidant activity. On the other hand, the extracts obtained by SWE at 150ºC for stems and bagasse and at 200ºC for musts presented more promising results, highlighting the Cerceal Branco stem sample with higher values of TPC (17.0 ± 0.2 mg GAE/g fw) and antioxidant activity (19.9 ± 0.3 and 13.0 ± 0.3 mg AAE/g fw, for ABTS and FRAP methods, respectively). In the 6 most promising extracts, it was determined the pH, the total sugars content and the phenolic profile by HPLC-DAD, verifying that these extracts were mainly composed by neochlorogenic and chlorogenic acids, catechin, epicatechin and caffeine. Afterwards, the 6 previously selected extracts were incorporated into gummies, whose final formulation was also optimized (8 g of agar, a ratio of 95:300 mL of water:orange juice, a formulation:extract ratio of 50:5 mL and 30 g of carob syrup as sweetener). The produced gums were characterized by evaluating TPC, TTC, total flavonoids, antioxidant activity by ABTS, FRAP and DPPH methods, soluble proteins, total sugars, pH and Maillard reaction products. The obtained results were not in agreement, and it was not possible to determine which produced gum presented more promising characteristics for commercialization. Regarding the sensory characteristics of the gums, the desired consistency was not obtained, and their useful life is also very short. In the future, it is still necessary to optimize some parameters of the gum recipe, such as the use of a stabilizing agent and the amount of extract to be added, to improve the sensory and functional properties of the gums.
The wine industry is one of the most important economic activities in Portugal. The main goal of this work is the characterization and incorporation of the by-products of wine production in the food industry as a source of bioactive compounds. For this, samples of must, stem and bagasse from two different grape varieties, Tinta Miúda and Cerceal Branco, were subjected to different extraction techniques (conventional, microwave-assisted, ultrasound assisted and subcritical with water at 100, 150 and 200ºC). To evaluate the efficiency of the applied extraction techniques, the extracts were characterized by determining the total phenolic (TPC) and total tannins (TTC) contents, as well as the antioxidant activity by the ABTS and FRAP methods. From the different extraction techniques tested it was found that the obtained extracts by UAE presented less favorable results for antioxidant activity. On the other hand, the extracts obtained by SWE at 150ºC for stems and bagasse and at 200ºC for musts presented more promising results, highlighting the Cerceal Branco stem sample with higher values of TPC (17.0 ± 0.2 mg GAE/g fw) and antioxidant activity (19.9 ± 0.3 and 13.0 ± 0.3 mg AAE/g fw, for ABTS and FRAP methods, respectively). In the 6 most promising extracts, it was determined the pH, the total sugars content and the phenolic profile by HPLC-DAD, verifying that these extracts were mainly composed by neochlorogenic and chlorogenic acids, catechin, epicatechin and caffeine. Afterwards, the 6 previously selected extracts were incorporated into gummies, whose final formulation was also optimized (8 g of agar, a ratio of 95:300 mL of water:orange juice, a formulation:extract ratio of 50:5 mL and 30 g of carob syrup as sweetener). The produced gums were characterized by evaluating TPC, TTC, total flavonoids, antioxidant activity by ABTS, FRAP and DPPH methods, soluble proteins, total sugars, pH and Maillard reaction products. The obtained results were not in agreement, and it was not possible to determine which produced gum presented more promising characteristics for commercialization. Regarding the sensory characteristics of the gums, the desired consistency was not obtained, and their useful life is also very short. In the future, it is still necessary to optimize some parameters of the gum recipe, such as the use of a stabilizing agent and the amount of extract to be added, to improve the sensory and functional properties of the gums.
Description
Keywords
subprodutos da indústria vinícola compostos bioativos técnicas de extração gomas funcionais