Fresh foods typically undergo various levels of processing, such as fractionation, thermal and chemical processes. The need for these processes goes beyond the diversification of flavors, as they can contribute to the viability of consumption, conservation, storage, transportation and the development of new products. Domestic cooking and the technological processes used in the manufacture of foods and nutraceuticals affect nutritional, functional and biological properties of the different components present in the food matrix, and it is essential to better understand these transformations in order to optimize the use of nutritional and therapeutic resources. Current literature indicates that heat treatment, for example, is related to the degradation of polyphenols and anthocyanins, while carotenoids seem to be the most thermostable compounds. More recent methods such as freeze-drying, ultraviolet radiation, and ultrasound have been studied with promising effects on food preservation. However, the complexity of food matrices and the interaction between compounds still represents a major challenge in this field. Therefore, the aim of this chapter is to review the main aspects of the literature on the effects of different processing methods on the most well-known and studied classes of bioactive compounds and their properties.