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Ao longo dos anos, o consumidor tem tido uma preocupação crescente em seguir uma dieta
saudável e equilibrada. Deste modo, a preferência por alimentos saúdaveis, como frutos e vegetais
tem sido cada vez mais evidente, sendo estes uma fonte de moléculas capazes de beneficiar a saúde
do consumidor, nomeadamente na prevenção de algumas doenças. O fruto da planta Solanum
melongena L. (beringela) pertence à família Solanaceae e surge como uma excelente alternativa
para integrar uma dieta saudável. Este fruto é uma importante fonte de nutrientes e compostos com
potencial bioativo, nomeadamente compostos antociânicos, cujo consumo intervém de forma
benéfica na saúde humana e, para além disso, são compostos que constituem uma alternativa aos
corantes artificiais utilizados como aditivos na indústria alimentar.
No presente trabalho de investigação foi realizada uma avaliação nutricional, química e
bioativa do fruto de S. melongena fazendo, separadamente, a avaliação da polpa, epicarpo e do
fruto completo. Tendo em conta a cor sugestiva do epicarpo da berinjela, foram realizados ensaios
de otimização do procedimento de extração, de modo a obter um extrato corante rico em
antocianinas.
O perfil nutricional (teor em proteínas, cinzas, gorduras, hidratos de carbono e energia) foi
determinado aplicando metodologias oficiais de análise de produtos alimentares (AOAC), o perfil
químico foi avaliado através da determinação dos açúcares livres utilizando um sistema de HPLCRI,
os ácidos orgânicos por UFLC-PDA, os ácidos gordos por GC-FID, os tocoferóis por HPLCfluorescência
e os compostos fenólicos (antociânicos e não antociânicos) por HPLC-DADESI/
MS. O potencial bioativo foi avaliado através de ensaios de atividade antioxidante, antiinflamatória
e antimicrobiana, bem como por ensaios de citotoxicidade e hepatotoxicidade em
linhas celulares tumorais humanas e cultura de células primárias não tumorais, respetivamente.
De acordo com os resultados, o fruto de S. melongena evidenciou um teor de humidade
superior a 90%, aquando da avaliação da polpa e do fruto inteiro. Foi também notório o baixo teor
em gordura, hidratos de carbono e valor energético, assim como, a presença de várias moléculas
de interesse, nomeadamente açúcares livres (frutose, glucose, sacarose e trealose), ácidos
orgânicos (oxálico, quínico, málico e fumárico) e ácidos gordos. Nestes últimos foram
identificados 17 compostos, destacando-se o ácido palmítico (C16:0) e o ácido esteárico (C18:0)
como maioritários, em ambas as amostras estudadas. Através da avaliação do perfil individual de compostos fenólicos não antociânicos foram
detectados os ácidos protocatecuico e 5-O-cafeoilquinico no epicarpo, e um hexósido do ácido
cafeico e o ácido 5-O-cafeoilquínico na polpa. O perfil individual de antocianina revelou a
presença de delfinidina 3-O-rutinósido na amostra de epicarpo.
Relativamente à atividade antioxidante, em ambos os ensaios aplicados foram evidentes
valores promissores de EC50, o que traduziu o excelente potencial bioativo dessa espécie. O mesmo
ocorreu com a atividade antimicrobiana, onde foram demonstrados o potencial bacteriostático e
bactericida contra algumas estirpes de bactérias. Foi, também, provada a ausência de toxicidade
em ambas as amostras testadas.
Posteriormente foi realizada a otimização do processo de extração, aplicando um desenho
experimental estatístico, que fornece dados suficientes para modelar matematicamente o
comportamento dos fatores de extração e as interações entre eles. Assim, a interpolação numérica
permitiu determinar e confirmar o ponto de extração ideal. Neste caso, tendo em conta as diferentes
respostas, as condições ótimas de extração do epicarpo, extrato e solvente recuperado foram,
respetivamente: Y1 (solvente = 64%; razão = 5 g/L; e tempo = 0,5 min), Y2= (solvente = 58%;
razão = 5 g/L; e tempo = 0,5 min), e Y3 (solvente = 54%; razão = 5 g/L; e tempo = 0,5 min). Em
valores gerais de otimização para as três respostas envolvidas: com um valor ótimo de
incapacidade de 0,99: 58,4% de concentração de etanol (v/v), 5 gramas de S. melongena por litro
de solvente e 0,5 min de tempo de extração. Estes parâmetros permitiram a obtenção de 11,96 mg
de antocianinas por g de extrato, mostrando um aumento significativo comparativamente com a
extração convencional (9,2 mg de antocianinas por g de extrato).
Este estudo mostrou que os frutos de S. melongena são uma boa opção para uma dieta
saudável, evidenciando um baixo teor lipídico e calórico, assim como a presença de moléculas
bioativas, como compostos fenólicos. Para além disso, comprovou que o epicarpo deste fruto é
rico em pigmentos naturais (antocianinas), podendo gerar grande interesse no setor industrial.
Over the years, the consumer has been increasingly concerned about following a healthy and balanced diet. In this way, the preference for healthy foods, such as fruits and vegetables has been increasingly evident, being these a source of molecules capable of benefiting consumer health, namely in the prevention of some diseases. The fruit of Solanum melongena L. plant (eggplant) belongs to the Solanaceae family and appears as an excellent alternative to integrate a healthy diet. This fruit is an important source of nutrients and compounds with bioactive potential, namely anthocyanin compounds, whose consumption has a beneficial effect on human health, and in addition, these compounds are an alternative to artificial colours used as additives in the food industry. In the present research work, the nutritional, chemical and bioactive evaluation of the fruit of S. melongena was carried out, performing separately the evaluation of the pulp, epicarp and the complete fruit (pulp and epicarp). Considering the sugestive colour of eggplant epicarp, tests were carried out to optimize the extraction procedure in order to obtain a colourant extract rich in anthocyanins. The nutritional profile (protein, ash, fat, carbohydrate and energy content) was determined by applying official methodologies for food analysis (AOAC), while the chemical profile was evaluated by determining free sugars using an HPLC-RI system, organic acids by UFLC-PDA, fatty acids by GC-FID, tocopherols by HPLC-fluorescence and phenolic compounds (anthocyanins and non-anthocyanins) by HPLC-DAD-ESI/MS. The bioactive potential was assessed through tests for antioxidant, anti-inflammatory and antimicrobial activity, as well as cytotoxicity and hepatotoxicity tests on human tumor cell lines and non-tumor primary cell culture, respectively. According to the results, the fruit of S. melongena showed a moisture content higher than 90% when evaluating the pulp and the whole fruit. It was also noted low values for fat, carbohydrate and energy, and the presence of various molecules of interest, namely free sugars (fructose, glucose, sucrose and trehalose), organic acids (oxalic, quinic, malic and fumaric) and fatty acids. In the latter, 17 compounds were identified, highlighting palmitic acid (C16:0) and stearic acid (C18:0) as the majority in both studied samples. Through the evaluation of the individual non-anthocyanin phenolic compounds, protocatechuic and 5-O-caffeoylquinic acids were detected in the epicarp, and caffeic acid hexoside and 5-O-caffeoylquinic acid were identified in the pulp. The anthocyanin profile revealed the presence of delphinidin 3-O-rutinoside in the epicarp. Regarding the antioxidant activity, both tested assays showed promising values of EC50, which translated the excellent bioactive potential of this species. The same happened with the antimicrobial activity, where the bacteriostatic and bactericidal potential against some bacteria strains were demonstrated. Was also proved the absence of toxicity in both resred samples. Afterwards, the optimization of the extraction process was performed, applying a statistical experimental design, which provides sufficient data to mathematically model the behavior of the extraction factors and the interactions between them. Thus, the numerical interpolation allowed to determine and confirm the optimum extraction point. In this case, taking into account the different responses, the optimal conditions of extraction of the epicarp, extract and recovered solvent were, respectively: Y1 (solvent = 64%; ratio = 5 g/L; and time = 0.5 min), Y2 (solvent = 58%; ratio = 5 g/L; and time = 0.5 min), and Y3 (solvent = 54%; ratio = 5 g/L; and time = 0.5 min). The general optimization values for the three responses involved: with an optimum value of deseability of 0.99, 58.4% of the ethanol concentration (v/v), 5 grams of S. melonera per liter of solvent and 0.5 min of extraction time. These parameters allowed the obtention of 11.96 mg of anthocyanins per g of extract, showing a significant increase compared to the conventional extraction (9.2 mg of anthocyanins per g of extract). This study showed that S. melongena fruits are a good option for a healthy diet, showing a low lipid and caloric content, as well as the presence of bioactive molecules, such as phenolic compounds. In addition, was proved that the epicarp of this fruit is rich in natural pigments (anthocyanins), which can generate great interest in the industrial sector.
Over the years, the consumer has been increasingly concerned about following a healthy and balanced diet. In this way, the preference for healthy foods, such as fruits and vegetables has been increasingly evident, being these a source of molecules capable of benefiting consumer health, namely in the prevention of some diseases. The fruit of Solanum melongena L. plant (eggplant) belongs to the Solanaceae family and appears as an excellent alternative to integrate a healthy diet. This fruit is an important source of nutrients and compounds with bioactive potential, namely anthocyanin compounds, whose consumption has a beneficial effect on human health, and in addition, these compounds are an alternative to artificial colours used as additives in the food industry. In the present research work, the nutritional, chemical and bioactive evaluation of the fruit of S. melongena was carried out, performing separately the evaluation of the pulp, epicarp and the complete fruit (pulp and epicarp). Considering the sugestive colour of eggplant epicarp, tests were carried out to optimize the extraction procedure in order to obtain a colourant extract rich in anthocyanins. The nutritional profile (protein, ash, fat, carbohydrate and energy content) was determined by applying official methodologies for food analysis (AOAC), while the chemical profile was evaluated by determining free sugars using an HPLC-RI system, organic acids by UFLC-PDA, fatty acids by GC-FID, tocopherols by HPLC-fluorescence and phenolic compounds (anthocyanins and non-anthocyanins) by HPLC-DAD-ESI/MS. The bioactive potential was assessed through tests for antioxidant, anti-inflammatory and antimicrobial activity, as well as cytotoxicity and hepatotoxicity tests on human tumor cell lines and non-tumor primary cell culture, respectively. According to the results, the fruit of S. melongena showed a moisture content higher than 90% when evaluating the pulp and the whole fruit. It was also noted low values for fat, carbohydrate and energy, and the presence of various molecules of interest, namely free sugars (fructose, glucose, sucrose and trehalose), organic acids (oxalic, quinic, malic and fumaric) and fatty acids. In the latter, 17 compounds were identified, highlighting palmitic acid (C16:0) and stearic acid (C18:0) as the majority in both studied samples. Through the evaluation of the individual non-anthocyanin phenolic compounds, protocatechuic and 5-O-caffeoylquinic acids were detected in the epicarp, and caffeic acid hexoside and 5-O-caffeoylquinic acid were identified in the pulp. The anthocyanin profile revealed the presence of delphinidin 3-O-rutinoside in the epicarp. Regarding the antioxidant activity, both tested assays showed promising values of EC50, which translated the excellent bioactive potential of this species. The same happened with the antimicrobial activity, where the bacteriostatic and bactericidal potential against some bacteria strains were demonstrated. Was also proved the absence of toxicity in both resred samples. Afterwards, the optimization of the extraction process was performed, applying a statistical experimental design, which provides sufficient data to mathematically model the behavior of the extraction factors and the interactions between them. Thus, the numerical interpolation allowed to determine and confirm the optimum extraction point. In this case, taking into account the different responses, the optimal conditions of extraction of the epicarp, extract and recovered solvent were, respectively: Y1 (solvent = 64%; ratio = 5 g/L; and time = 0.5 min), Y2 (solvent = 58%; ratio = 5 g/L; and time = 0.5 min), and Y3 (solvent = 54%; ratio = 5 g/L; and time = 0.5 min). The general optimization values for the three responses involved: with an optimum value of deseability of 0.99, 58.4% of the ethanol concentration (v/v), 5 grams of S. melonera per liter of solvent and 0.5 min of extraction time. These parameters allowed the obtention of 11.96 mg of anthocyanins per g of extract, showing a significant increase compared to the conventional extraction (9.2 mg of anthocyanins per g of extract). This study showed that S. melongena fruits are a good option for a healthy diet, showing a low lipid and caloric content, as well as the presence of bioactive molecules, such as phenolic compounds. In addition, was proved that the epicarp of this fruit is rich in natural pigments (anthocyanins), which can generate great interest in the industrial sector.
Descrição
Palavras-chave
Antocianinas Beringela Bioatividade Corante natural