Bioaccessibility and antioxidant activity of anthocyanins from jaboticaba skins: the influence of OSA-modified starch concentration

In recent years, there has been a growing interest in clarifying the metabolism of bioactive compounds, particularly phenolics such as anthocyanins. The transformation of anthocyanins from jaboticaba throughout digestion has yet to be extensively investigated. Due to native-form anthocyanins' instability against environmental stress, bioactive compounds are not always as effective in improving human health as they could be. The microencapsulation of material with high levels of anthocyanins by freeze-drying usually results in products with greater stability during storage, preserving their antioxidant properties. Therefore, the main goal of the present study was to determine the bioaccessibility of anthocyanins in jaboticaba powder samples to evaluate the effects of the modified starch with octenyl succinic anhydride (OSA) concentration (10% of adjuvant (PA), jaboticaba powder with 15% of adjuvant (PB), jaboticaba powder with 20% of adjuvant (PC), jaboticaba powder with 25% of adjuvant (PD)) using a static in vitro model of digestion over the anthocyanin’s contents and their antioxidant activities. Based on the results, it is possible to observe a decrease in anthocyanin content after the simulated digestive process. Before the digestion, the anthocyanins concentration values ranged from 94.30e ± 4.1 to 257.95a ± 22.8 ug/mL of cyanidin 3-glucoside. The highest concentration was found on jabuticaba pulp (JP) and the lowest on jaboticaba powder with 25% OSA-modified starch (PD). However, after the in vitro digestion, the loss of anthocyanins was more accentuated in the samples JP, PC, and PD. The bioaccessible anthocyanins varied from 5.30 (PC) to 9.58 (PB). Therefore, the PB sample presented the best results among the studied in the present work. The interaction between adjuvant and bioactive compounds promoted the protection of bioactive compounds against adverse digestion conditions, considering the maintenance of antioxidant activity

A incorporação de polpa de juçara em nanoestruturas é uma alternativa eficaz para potencializar os efeitos biológicos das antocianinas?

A polpa da juçara é proveniente da palmeira Euterpe edulis Mart., nativa da Mata Atlântica e sua composição apresenta elevado teor de compostos fenólicos, principalmente as antocianinas. As antocianinas são pigmentos naturais e conferem diversos efeitos biológicos benéficos à saúde, incluindo sua ação antioxidante, podendo assim, proporcionar a prevenção de doenças crônicas não transmissíveis. Em contrapartida, essa classe de pigmentos naturais possui baixa estabilidade depois de extraída da matriz alimentar, além de baixa bioacessibilidade, e capacidade de absorção, de forma que apenas uma porção do que é consumido é absorvida pelo organismo. Mesmo com resultados promissores, as pesquisas desenvolvidas até o momento ainda não são suficientes para garantir a máxima eficácia da ação biológica desse pigmento. Dentre as alternativas que podem potencializar a ação das antocianinas, se destaca sua incorporação em nanoestruturas, uma vez que há estudos demonstrando um aumento da proteção de compostos bioativos nanoencapsulados contra fatores adversos, como as reações durante o processo digestivo, ou mesmo durante o processamento de alimentos na indústria de alimentos, além de potencializar sua capacidade absortiva. O presente estudo teve como objetivo verificar o efeito biológico das antocianinas da polpa de juçara, da polpa de juçara fermentada, das soluções poliméricas contendo ambas e das nanoestruturas com as polpas, produzidas pela técnica de electrospinning utilizando o polímero óxido de polietileno. Para tanto, algumas respostas foram avaliadas desde a quantificação de antocianinas utilizando sistema HPLC-PDA, passando pela determinação da atividade antioxidante de cada fase da digestão simulada (oral, gástrica e intestinal), além da quantificação de antocianinas absorvidas considerando o modelo celular constituído por monocamadas de células Caco-2. Foram observados resultados promissores provenientes das soluções poliméricas com polpa de juçara in natura e fermentada, uma vez que a polpa de juçara adicionada de polímero e as nanofibras apresentaram valores melhores de manutenção da atividade antioxidante (82,9% e 64,4% para ABTS e ORAC, respectivamente para a solução polimérica e 85,3% e 75,1%, para ABTS e ORAC respectivamente, para as nanofibras) do que a polpa in natura (59,5% e 54,6% para ABTS e ORAC, respectivamente), o mesmo foi constatado para a polpa fermentada, a solução polimérica com juçara fermentada apresentou 83,4% e 67,4% para ABTS e ORAC, respectivamente, de manutenção da ação antioxidante, enquanto a polpa fermentada livre apresentou 31,1% e 45% para ABTS e ORAC, respectivamente. As conformações de solução polimérica e de nanofibra demonstraram seu efeito protetor para com os compostos bioativos através da manutenção da atividade antioxidante após a digestão in vitro.The jussara pulp is derived from Euterpe edulis Mart. palm tree, native to Atlantic Forest, and its composition presents a high content of phenolic compounds, such as anthocyanins. The anthocyanins are natural pigments and provide several biological effects to human health, including their antioxidant activity, thus preventing chronic non-transmissible diseases. In contrast, this class of natural pigments has low stability after being extracted from the food matrix, besides low bioaccessibility and absorption capacity, just a portion of what is consumed is absorbed by the human organism, even with promising results that the researchers developed until the present are not enough to guarantee the maximum effectiveness of this pigment biological action. Among the alternatives which may improve the anthocyanin's response, their incorporation into nanostructures is a highlight, since studies are showing an increase in the protection of nanoencapsulated bioactive compounds against adverse factors, such as reactions during the digestive process, or even during the processing of foods in the food industry, in addition to enhancing their absorptive capacity. The present study aimed to verify the biological effects of anthocyanins from jussara pulp, jussara pulp fermented, polymer solutions containing both and nanostructures with the pulps, produced by the electrospinning technique using poly(ethylene oxide) polymer. Therefore, some responses were evaluated from the quantification of anthocyanins utilizing the HPLC-DAD system, through the antioxidant activity of each stage of the simulated digestion (oral, gastric, and intestinal), in addition to the quantification of absorbed anthocyanins considering the cell model related by Caco-2 cells monolayers. Promising results were observed from polymer solutions and nanofibers containing in natura and fermented jussara pulp, since the polymer and nanofibers with jussara pulp presented better maintenance values of the antioxidant activity (82.9% and 64.4% for ABTS and ORAC, respectively, for a polymeric solution and 85.3% and 75.1%, for ABTS and ORAC respectively, for nanofibers) than the free pulp (59.5% and 54.6% for ABTS and ORAC, respectively), the same was seen for the fermented pulp, the solution form presented 83.4% and 67.4% for ABTS and ORAC, respectively, of maintenance of the antioxidant action, while the free fermented pulp presented 31.1% and 45% for ABTS and ORAC, respectively. The conformations of polymeric solution and nanofiber had their protective effect for bioactive compounds through the maintenance of antioxidant activity after in vitro digestion.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)2020/03560-

Nanofibers of Jussara Pulp: A Tool to Prevent the Loss of Thermal Stability and the Antioxidant Activity of Anthocyanins after Simulated Digestion

Electrospinning can produce a new composite for coating sensitive bioactive compounds, such as anthocyanins, and the product obtained from this process presents characteristics that potentialize the application of natural pigments in foodstuffs. The present work aimed to develop a new nanofiber composite with incorporated anthocyanins from jussara pulp using polyethylene oxide through electrospinning. A decay in the percentage of anthocyanins during digestion was observed. However, the polymeric solution and composites produced maintained the antioxidant activity, showing their protective effect on bioactive compounds; furthermore, both nanofibers and polymer solution improved the thermal stability of the anthocyanins. Thus, the results obtained potentiate electrospinning composites in processed food products since the nanofibers presented superior thermal stability and antioxidant activity, even after the digestion process in vitro