Bioactive compounds of citrus as health promoters

Citrus are a group of fruit species, quite heterogeneous in many aspects, including chemical composition of the fruit. Since ancient times, some citrus fruits were used to prevent and cure human diseases. In the recent decades, it has been demonstrated that fruits can actually help prevent and cure some diseases and above all, they are essential in a balanced diet. Citrus fruits, as one of the groups of fruit species, with greater importance in the world, have been studied for their effects on human health. Some species of citrus were referred as potential antioxidant based therapy for heart disease, cancer and inflammation. Fruit peels and seeds have also high antioxidant activity. The health benefits of citrus fruit have mainly been attributed to the high level of bioactive compounds, such as phenols (e.g., flavanone glycosides, hydroxycinnamic acids), carotenoids and vitamin C. These compounds are present in the fruit pulp and hence in the juice. But some bioactive compounds can be found in parts of the fruit which usually are not used for human food. The content of bioactive compounds depends on the species and cultivar, but also depends on the production system followed in the orchard. Citrus fruits, their derivatives and their by-products (peel, pulp and oil) are reach in different bioactive compounds and its maturity, postharvest and agroindustry processes influence their composition and concentration. The aim of this chapter was to review the main bioactive compounds of the different components of citrus and their relationship to health.

Compostos bioativos de microalgas com interesse no tratamento da diabetes

Dissertação de Mestrado, Biologia Molecular e Microbiana, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016

Marine photosynthetic organisms from the Portuguese coast as sources of antitumoural compounds

Dissertação de Mestrado, Ciências Biomédicas, Departamento de Ciências Biomédicas e Medicina, Universidade do Algarve, 2016

Effect of fertilization and type of pruning on quality of fresh and dehydrated Stevia rebaudiana

Mestrado em Engenharia Alimentar - Instituto Superior de Agronomia - UL

Valorização integrada de resíduos e subprodutos da extração do azeite: extração e caraterização de compostos bioativos do bagaço de azeitona

Dissertação de Mestrado, Tecnologia de Alimentos, Instituto Superior de Engenharia, Universidade do Algarve, 2016

Natural plant polyphenols for alleviating oxidative damage in man: Current status and future perspectives

The balance between oxidation and reduction is important for maintaining a healthy biological system. Oxidative stress results from an imbalance between excessive formation of reactive oxygen species (ROS) and/or reactive nitrogen species (RNS) and limited endogenous defense systems, and this imbalance can adversely alter lipids, proteins and DNA, causing a number of human diseases. Thus, exogenous antioxidants that can neutralize the effect of free radicals are needed to diminish the cumulative effects of oxidative damage over human life span. Current research reveals that phenolic compounds in plants possess high antioxidant activity and free radical scavenging capacity and can prevent the body from oxidative damage over human life span. This review focuses on the present understanding of free radicals and antioxidants and their importance in human health and disease. Information about the chemical features of free radicals as well as their deleterious effects on cell structures is reviewed. The chemical structure and anti-oxidative mechanisms of essential polyphenols and their potential health benefits are presented. In addition, the limitation of natural antioxidants and a perspective on likely future trends in this field are also discussed.

Estudo de composto com propriedades funcionais em flor de cardo submetida a diferentes tratamentos de secagem

O cardo é uma planta que encontra-se associada ao fabrico de queijo, pois é responsável pelo fenómeno da coagulação do leite. No entanto, têm aumentado o número de estudos realizados nesta planta, relacionados com a composição química, de forma a perceber os benefícios para a saúde. O objetivo desta dissertação foi caracterizar a flor de cardo relativamente à sua atividade antioxidante, composição em compostos fenólicos e avaliar a sua estabilidade ao longo do trato digestivo. Para tal, foram estudas amostras de flor de cardo da espécie C. cardunculus spp flavescens, após liofilização e secagem em estufa com convecção forçada a diferentes temperaturas (40ºC, 50ºC e 60ºC). Após cada tratamento, efetuaram-se duas extrações sucessivas com soluções de metanol (98% v/v) e de acetona (60% v/v). Os extratos obtidos foram depois utilizados para quantificar os teores em compostos fenólicos totais, em orto-difenois e em flavonóides. A atividade antioxidante foi determinada utilizando os métodos DPPH e ABTS. Por fim, procedeu-se à avaliação da bioacessibilidade dos compostos presentes submetendo os vários extratos a condições simulantes do trato digestivo. Pela análise dos resultados obtidos foi possível constatar que a quantidade de compostos fenólicos e atividade antioxidante na flor de cardo varia consoante a temperatura de secagem, ocorrendo a diminuição à medida que se aumenta a temperatura. Os resultados obtidos para a bioacessibilidade mostraram um comportamento distinto dos extratos de metanol e de acetona. No entanto, em ambos os casos ocorreu uma diminuição na quantidade de compostos disponíveis para absorção intestinal.

Effect of drying on the physical, chemical and sensorial properties of kiwi

Kiwi fruit is a highly nutritional fruit due to the high level of vitamin C and its strong antioxidant capacity due to a wide number of phytonutrients including carotenoids, lutein, phenolics, flavonoids and chlorophyll [1]. Drying consists of a complex process in which simultaneous heat and mass transfer occur. Several alterations occur during the drying of foods at many levels (physical, chemical, nutritional or sensorial) which are influenced by a number of factors, including processing conditions [2]. Temperature is particularly important because of the effects it produces at the chemical and also at the physical level, particularly colour and texture [3]. In the present work were evaluated the changes in sliced kiwi when exposed to air drying at different temperatures (50, 60, 70, 80 ºC), namely in terms of some chemical properties like ascorbic acid or phenolic compounds, physical characteristics like colour and texture and also at the sensorial level. All experiments followed standard established procedures and several replicates were done to assess each property. The results obtained indicated that moisture was reduced with drying by 74 to 87%, depending on the temperature. Also ascorbic acid decreased with drying, being 7% for 50 ºC and increasing up to 28% for the highest temperature (80 ºC). The phenolic compounds and antioxidant activity were also very much affected by the drying temperature. The water activity of the dried samples varied from 0.658 to 0.753, being compatible with a good preservation. Regarding colour, the total colour difference between the dried samples and the fresh sample was found to vary in the range 9.45 – 17.17. The textural parameters were also much affected by drying, namely hardness which decreased by 45 to 72 %, and all other parameters increased: cohesiveness (approximately doubled), springiness (increased 2 to 3 times) and chewiness which increased up to 2.5 times that off the fresh sample. Adhesiveness, which was observed for the fresh samples (-4.02 N.s) disappeared in all the dried samples. The sensorial analysis made to the dried samples allowed establishing the sensorial profiles as shown in Figure 1.

Study of extraction conditions for phenolic compounds from Strawberry fruits

Strawberries are an important source of phytochemicals, namely vitamins and phenolic compounds such as anthocyanins and tannins with antioxidant properties [1]. The yield and phenolic content of natural extracts are dependent on the conditions used for extraction [2]. In the present work three different types of extracting solutions (methanol, ethanol:water and aceton:water), two times of extraction (15 and 60 min) and three ratios of solid/solvent (5/25, 5/50 and 5/100 g/mL) were tested in order to evaluate the efficiency of the extraction of phenolic compounds. Phenolic compounds were determined by Folin-Ciocalteu method [3]. Each assay was performed in triplicate. Regarding the extraction solution, it was possible to observe a slight tendency towards a higher efficiency of acetone:water (AcO:H2O, 60:40), but the differences mioght not be statistically significant. A longer time of contact, 60 min as opposed to 15 min, did not show advantages in the yield of extraction. Considering the factors under study, the results obtained showed that volume of extraction solution was the parameter that most influenced the values obtained. Using a higher volume lead to an increase in the amount of phenolic compounds extracted, in a more pronounced way for 15 min of extraction. For a volume of 25 mL the amount of phenolic compounds quantified ranged from 2.13-2.41 mg GAE/g, and increased 30-68% when it was used 50 mL of solution. Using 100 mL of solution, it was extracted twice as double of phenolic compounds. In case of 60 min, the amount of phenolic compounds quantified in samples obtained with 25 mL of solution ranged from 2.32-2.97 mg GAE/g, and increased for 2.43-4.27 mg GAE/g and 3.98-4.68 mg GAE/g when was used 50 and 100 mL, respectively.

Bioactive Phenols in Small Fruits and Berries

Bioactive compounds are extra nutritional constituents occurring naturally in plant foods in small amounts, however in quantities enough to produce bioactive effects. Among bioactive compounds the phenolic compounds are a very large set of molecules, which include several groups such as for example flavonoids, phenolic acids or tannins. Small fruits and berries include a wide diversity of fruits, like grapes, strawberries, blackberries, blueberries, raspberries, cherries, hardi kiwi, gooseberries, cranberries, currants (black, white, red), physalis, crowberries, açaí, elderberries, dates or goji berries, and these frequently have been reported as having particularly high concentrations of phenolic compounds with antioxidant activity. Hence, the objective of this chapter is to review the literature about the type and contents of different phenolic compounds present in small fruits and berries, as well as their bioactive properties, including antioxidant capacity. All the fruits and berries investigated in this chapter were particularly rich in bioactive compounds, including phenolic compounds that provide the fruits with high antioxidant properties. The most relevant health promoting effects include anti-cancer, anti-inflamatory, neuro protective, cardio protective or anti-diabetes, thus indicating that these foods are a valuable resource to prevent and treat diseases.

Chemical Composition and Bioactive Compounds in Bananas and Postharvest Alterations

Bananas arise as one of the most popular fruits consumed all around the world. Banana belongs to the genus Musa from the family Musaceae. It is original from tropical regions and presents a strong ability to protect itself from the oxidative stress caused by extreme climatic conditions such as intense sunshine and high temperature. For this protection, bananas increase the production of bioactive compounds with antioxidant activity, which protect the fruit from the oxidative damage. Scientific studies have demonstrated that bananas (both in the pulp and peel) contain different antioxidant compounds, like vitamins (A, B, C and E), β-carotene and phenolic compounds (catechin, epicatechin, lignin, tannins, anthocyanins). Furthermore, banana is also notably rich in minerals, like potassium and phosphorus. The knowledge about the chemical composition and the contents in compounds with biological activity is of high interest given the importance of bananas as a valuable food all over the world. However, because bananas are perishable due to some factors like chemical reactions, including those that result in the production of ethylene, their postharvest conservation in pivotal for the commercialization. The effects of postharvest treatments and storage conditions on the composition of bananas are, therefore, essential. In this way, the present chapter focus on the composition of bananas, including macronutrients, micronutrients and bioactive compounds, as well as the effect of postharvest treatments and storage conditions in the quality of bananas.

Life history & environmental effects on telomere dynamics in Atlantic salmon

While much of the study of molecular biology inevitably focuses on the parts of the genome that contain active genes, there are also non-coding regions that nonetheless play an essential role in maintaining genome integrity. One such region are telomeres, which cap the ends of all eukaryotic chromosomes and play an important role in chromosome protection. Telomere loss occurs at each cell division as a result of the ‘end replication problem’ and a relatively short telomere length is indicative of poor biological state. Thus far, the majority of studies on the dynamics and role of telomeres have been biased towards certain taxa. Research to date has mostly focussed on humans, other mammals and birds. There has been far less research on the telomere dynamics of ectotherms. It is important that we do so, especially since ectothermic vertebrates do not seem to down-regulate telomerase expression in the same way as endotherms, suggesting that their telomere dynamics may be less predictable in the later life stages. The main objective of this thesis was therefore to investigate how life history and environmental effects may influence telomere dynamics in Atlantic salmon Salmo salar. I carried out carefully designed experiments, both in the laboratory and in the wild, using a longitudinal approach where possible, in order to address a number of specific questions that are connected to this central theme. In chapter 2, I demonstrate that there can be significant links between parental life history and offspring telomere dynamics. Maternal life history traits, in particular egg size, were most strongly related to offspring telomere length at the embryonic stages. Paternal life history traits, such as early life growth rate, had a greater association with offspring telomere dynamics in the later stages of development. In chapter 3, using a wild Atlantic salmon population, I found that most individuals experienced a reduction in telomere length during the migratory phase of their life cycle; however the relative rate of telomere loss was dependent on sex, with males experiencing a relatively greater loss. Unexpectedly, I also found that juvenile salmon that had the shortest telomeres at the time of outward migration, had the greatest probability of surviving through to the return migration. In chapter 4, again using a wild system involving experimental manipulations of juvenile Atlantic salmon in Scottish streams, I found that telomere length in juvenile fish was influenced by parental traits and by direct environmental effects. Faster-growing fish had shorter telomeres and there was a greater cost (in terms of reduced telomere length) if the growth occurred in a harsher environment. I also found a positive association between offspring telomere length and the growth history of their fathers (but not mothers), represented by the number of years that fathers had spent at sea. Chapter 5 explored the hypotheses that oxidative DNA damage, catalase (CAT) antioxidant activity and cell proliferation rate are underlying mechanisms linking incubation temperature and telomere dynamics in salmon embryos. No evidence was found for any such effects, but telomere lengths in salmon embryos were found to be significantly affected by the temperature of the water in which they were living. There is also evidence that telomere length significantly increases during embryonic development. In summary, this thesis has shown that a complex mix of environmental and parental effects appear to influence telomere dynamics in Atlantic salmon, with parental effects especially evident during early life stages. It also demonstrated that telomeres lengthen through the embryo stages of development before reducing once the fry begin feeding, indicating that the patterns of telomere loss commonly found in endotherms may differ in ectotherms. Reasons for this variation in telomere dynamics are presented in the final Discussion chapter of the thesis.