Food or medicine? That is the question related to our everyday lives. Fruits are an important part of daily nutritional habits and can be recognised as a supplier of vitamins, minerals, fibers, antioxidants, etc. On the other hand, however, they can influence our GUT microflora and can have a direct and indirect impact on our health. Our ancestors had no knowledge of plant taxonomy, enzymes, antioxidants, or microbiology; they even knew nothing about the existence of the microbes and all these molecules. However, they had one very powerful piece of knowledge, and that was knowledge of traditional know-how. Based on personal experience and the knowledge transferred from parents to children throughout the centuries, they knew about the beneficial properties of fruits, vegetables, and medical plants. The longest part of this history was based on empirical knowledge gained by experience without former knowledge of either mechanisms or scientific basis. If we look back in history, we can find the use of various fruits, vegetables and medical plants in the treatment of numerous diseases; they appreciated for their nutritional value or used in everyday domestic processes. Based on empiric experience, a high number of fruits have been used in traditional medicine. Empiric knowledge, frequently transferred from one generation to the next, was the only basis for preparation and application of these products in the past. Mangos (Mangifera indica L.) and guavas (Psidium guajava) have been widely acknowledged as nutritionally valuable fruits that act excellent sources of vitamins and minerals. They have been cultivated in tropical and subtropical parts of the world. Many research investigations reveal that both plants exhibit numerous medicinal properties. They have been used to treat many ailments by acting as antioxidants, antidiabetics, anti-inflammatory agents, anti-diarrhea supplements, aiding with hypolipidaemia, and anti-cancer promoters. Mangos have been found to be widely used in food, cosmetic and pharmaceutical industries, while guavas are processed mainly into food products. However, their physical, chemical, and sensory attributes of undergo changes upon the ripening process. Thus, different methods of storage and packaging are developed to prolong the shelf life and maintain the quality of these fruits. From the viewpoint of the twenty-first century scientist, we have sufficient knowledge to address various beneficial properties to mangos and guavas. Nowadays, the application of different parts of the mango and guava plants could be seen in the preparation of numerous bioactive molecules. These molecules include enzymes, antibacterial proteins, antioxidants, and various extracts applicable in modern medicine, food industry, etc. In this book, we have tried to collect materials covering some aspects from characterisation and origin of the mango and guava plants into the taxonomical position of the plants to summarise information about the application of the fruits and other parts of their plants.

Within the tropical fruits, the papaya, Carica papaya L. (family Caricaceae Dumort.), is presented as the main representative being cultivated in tropical and sub-tropical areas mostly in developing countries. Papaya's nutritional value, beneficial to health, as well as various industrial applications of their products, led to be economically important for both developing and developed countries. Within this broad field of knowledge, this book aims to contribute to better understanding of the topic. The organization of the chapters and sections is also straightforward; Chapter One presents what papaya is (Carica papaya L.), its taxonomy, distribution, origin and morphology. Closing the first part, Chapters Three and Four show the nutritional and medical values, discussing vitamins, minerals and dietary fibers, the industrial applications of using papaya and various parts of the plant, as a source of proteolytic enzymes and some active compounds reported to antimicrobial, anticancer, amongst other properties, illustrating the fatty acid composition, triacylglycerol profile and papaya seed oil of malaysian papaya fruits. In the second part of the book, the readers should find the relevant aspects of papaya microbiology related to fresh fruits quality and safety and the beneficial effects of microorganisms isolated from papaya, such as some Latic Acid Bacteria strains that have been proposed to be potentially probiotics, as shown in Chapters Five and Six. Finally the book addresses the importance of Integrated Management of the Papaya Ringspot Virus, which is transmitted by several aphid species and could commit 100% of the crop as described in Chapter Seven and the biotechnological strategies for control of papaya virus diseases as show in Chapter Eight.

Fruits from the Amazon region are highly appreciated for their exotic characteristics and have been a subject of interest and research since European pioneers discovered this rainforest. Numerous edible fruits from the Amazon region are considered to be rich sources of protein, though their bioactive metabolites are not used wisely worldwide despite being partly consumed by local communities. However, some of them are globally recognised and commercialised, such as guarana, acai, chestnuts from the Amazon (Brazilian nuts), and cacao. Some other exotic fruits like babacu, bacuri, buriti, euterpe, camu-camu, cupuacu, cubiu, dende, graviola, piquia, pupunha and tucuma may be better exploited in order to be aggregated to feed the general population. The application of these fruits was always explored by the traditional medicine of pre-Colombian tribes living in the Amazon region; however, the modern pharmaceutical industry is showing great interest in these fruits as a source of potential bioactive molecules with potential applications in the treatment of several diseases, including some types of cancers, diabetes, Alzheimers disease, the control of blood pressure, etc., Perhaps this is a realisation of Hippocrates dream -- that one day our food will be a form of medicine.