Browsing by Author "Lima, M. J."
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- Extração de compostos fenólicos de caroço de cerejaPublication . Dulyanska, Yuliya; Guiné, Raquel P. F.; valente, Luisa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Cardoso, Ana Paula; Barroca, Maria João; Silva, Aida Moreira; Lima, M. J.Os resíduos agroalimentares provaram ser um biorecurso que pode ser usado para obter uma variedade de materiais, ingredientes e produtos químicos valiosos. Neste trabalho foram testadas as condições ótimas para extração de compostos bioativos dos caroços de cereja com diferentes solventes e temperaturas. Os critérios escolhidos basearam-se na capacidade de extração mais eficiente, buscando técnicas mais limpas e com menor impacto no meio ambiente. Alguns solventes de extração foram testados em diferentes combinações e temperaturas. Os extratos obtidos foram avaliados utilizando métodos espectrofotométricos quanto a compostos fenólicos totais, bem como algumas famílias de compostos fenólicos. Os resultados obtidos mostraram que a maior extração de compostos fenólicos totais foi a 70°C com razão água:etanol de 60:40 (% v/v) (2,65 mg GAE/g), enquanto os máximos resultados para flavonoides foram obtidos a 80°C e solução aquosa etanólica 50% (7,26 mg QE/g). O maior valor para orto-difenóis foi de 21,47 mg GAE/g para 50°C e solução água:etanol 50:50. As maiores quantidades de proantocianidinas e flavonóis foram obtidas para solução 50:50 a 70 °C (6,43 mg CE/g e 3,88 mg QE/g, respetivamente), enquanto a mesma solução a 80 °C permitiu obter o máximo de ácidos fenólicos (1,68 mg CAE/ g). A extração de antocianinas varia significativamente com a concentração e temperatura, sendo mais alta na faixa de 35-40 °C, quando se utiliza uma solução de água:etanol 80:20. Em conclusão, verificou-se que os extratos de caroços de cereja obtidos possuem compostos bioativos relevantes com aplicações nas indústrias alimentícia, farmacêutica ou cosmética.
- The effect of nutrition on neurodegenerative diseasesPublication . Lima, M. J.; Guiné, Raquel P. F.Neurodegenerative diseases (NDD) are characterized by the progressive dysfunction and degeneration of neurons in the brain and peripheral nervous system, caused by a diversity of factors. State of the art on risk factors to develop neurodegenerative diseases (age, genetics and heredity, lifestyle, and exposition to certain substances or oxidative stress) is extensive. This chapter highlights the role of nutrition and dietary habits in neurodegenerative diseases and their beneficial role in preventing/delaying neurodegenerative disorders, which has gained tremendous prominence in recent years. Aging is the most significant risk factor for many of the known neurodegenerative diseases. Hence, it becomes crucial to define interventions that extend lifespan and protect against these damaging disorders. There is compelling evidence that exercise and oxidative stress can lead to the onset of several human problems, so a diet rich in antioxidants may help postpone or guide the progressive processes associated with these diseases. This chapter addresses the role of specific diets (Mediterranean, energy restriction, among others) and food components on delaying complications resulting from NDDs.
- The impact of extraction temperature and solution concentration on the antioxidant activity of sweet cherry seeds’ extractsPublication . Dulyanska, Y.; Cunha, Margarida; Lima, M. J.; Correia, Paula; Ferreira, Manuela; Fragata, Anabela; Cardoso, Ana Paula; Barroca, Maria João; Silva, A.; Cruz-Lopes, Luísa; Esteves, Bruno; Ferreira, José; Domingos, Idalina; Guiné, Raquel P. F.Sweet cherry seeds, a valuable lignin-cellulose raw material for the production of polyurethane foams 1, are also a significant source of different phenolic compounds 2 and can be a good source of natural antioxidants, which can play an important role in preventing the formation of free radicals and protection against degenerative diseases. Considering sustainability, the main objective of this project was the use of cherry by-products (seeds) to produce extracts rich in antioxidant compounds. In this work, the seed extracts were obtained with the addition of different combinations of ethanolic solution (water:ethanol ratios - 50:50; 60:40; 80:20; 100:0 v:v) and at different temperatures (35, 50, 70 and 80 °C), all under magnetic stirring for 40 minutes. Then, the antioxidant activity of the extracts was evaluated through spectrophotometric methods, using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid)) radicals, and also the Ferric Reducing Antioxidant Power Assay (FRAP). All measurements were replicated at least in triplicates and were expressed as mg Trolox equivalents per gram (mg TE/g). Statistical analysis was performed using the JAVA software. ANOVA tests show that there is a statistically significant effect of temperature, water percentage and temperature on the antioxidant activity evaluated by the three methods used (p> 0.001 in all tests). The percentage of water is the variable that most contributes to this effect. Individual Post Hoc comparisons show, for all tests, that in general the temperatures induce differences in antioxidant activity, except 70 °C and 80 °C in DPPH and FRAP, and 80 °C and 50 °C in ABTS. Regarding the percentage of water, it was found that all samples are different from each other, except the FRAP, in which no significant differences between 50 and 60% of water were found. In conclusion, no major differences between the ABTS, DPPH and FRAP methods were found. Temperature and percentage of water have a significant effect on the concentration of antioxidant activity in all methods. In that way, the cherry pit is a good by-product to produce extracts with high content of antioxidant activity, being that the 70° C with 50:50 and 60:40 water:ethanol solutions are the most favorable conditions to potentiate the antioxidant activity.