ESAV - DIA - Capítulo em obra internacional, como autor
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- Osmotic Dehydration of FruitsPublication . Guiné, Raquel; Barroca, Maria JoãoThe need for increasing improvements in the quality of food products conducted to an increased interest in osmotic treatment. This technology involves the partial dehydration of a water-rich solid foodstuff, either whole or in pieces, through immersion in an osmotic solution. In fact, osmotic treatment is applied with the goal of modifying the composition of food material through partial water removal and impregnation of solutes, without affecting the structural integrity of products. Three kinds of osmotic treatments have been used, depending on the pressure applied on the system: OD (osmotic dehydration at atmospheric pressure), VOD (osmotic dehydration at vacuum pressure) and PVOD (pulsed vacuum osmotic dehydration). However, the most common are OD and VOD technologies. Some of the potential applications of osmotic treatment in food technology include: (i) the development of compositionally formulated products by introducing functional food ingredients, such as firming agents, antioxidants, antimicrobial and nutraceuticals; (ii) preserving color, texture, natural flavor and aroma and any heat-sensitive nutrient components; and (iii) pre-treatment before freeze-drying for improving final product quality. However, the osmotic treatment on this wide range of applications requires an appropriate choice and control of operating conditions, such as processing temperature, pressure, time, composition, geometry of the food pieces and contact between the food pieces and the solution. The purpose of this chapter is to analyze the main effects of operating conditions and responses of the porous fruits to osmotic treatment, both at atmospheric and vacuum pressure, and to describe the important developments related to this technology in the fruit industry. Quality aspects of osmotic treatments on processed fruits, as well as technical challenges of this technique will also be discussed.
- Functional Components of Foods.Publication . Guiné, Raquel; Lima, Maria João; Barroca, Maria JoãoThe primary role of diet is to provide sufficient nutrients to meet the nutritional requirements of an individual. However, many professionals recognise that health promoting foods have a major role in health enhancement, which justifies the focus on research on the identification of biologically active components in foods that have the potential to optimise physical and mental well being and which may also reduce the risk of disease. Recent increases on research also aimed the identification of new functional foods and nutraceuticals as well as the establishment of scientific basis to support and validate the benefits of a particular food or component. Many traditional food products, including fruits, vegetables, soya, whole grains and milk, have been found to contain components with potential health benefits. In addition to these, new foods are being developed to enhance or incorporate these beneficial components to increase their health benefits or desirable physiological effects. The demand from consumers for healthful food has initiated a surge of research and product development in the food industry. In order to adapt to these consumer drivers, the food industry is reformulating food products to enhance the physiological functionality of inherent nutrients or by adding bioactives with largely clinically proven physiological function. In the present work, the characteristics of these “bioactive molecules” allied to their ability to prevent or cure certain diseases will be object of study.
- Functional Components of Foods.Publication . Guiné, Raquel; Lima, Maria João; Barroca, Maria JoãoNot available
- Effect of Processing on the Phenolic Compounds and Antioxidant Activity of Fruit JuicesPublication . Guiné, Raquel; Barroca, Maria JoãoResearch studies have been increasingly focused on plant polyphenols and their positive health effects. Among these stand the phenolic acids, flavonols, catechin monomers, proanthocyanidins, flavones, flavanones and anthocyanins, which decrease the risk of cancer and heart disease. The phenolic antioxidants from fruit juices have been widely investigated and characterised for their anticancer, anti-inflammatory and cardio protective properties. Focusing on fruit juices, consumers are highly interested in health claims of polyphenols in food products in general, and particularly regarding fruit juices, and therefore there is an increasing market in antioxidant fruit juices and formulation of juice mixtures with high polyphenol concentrations. However, this type of component is somewhat susceptible to thermal degradation, and hence the effects of processing, like pasteurization, are of wide interest. The aim of this chapter is to, on the one hand make an overview of the polyphenols present in different fruit juices, and their antioxidant activity, and on the other hand focus on the beneficial properties for health of such compounds, and finally to overview the effect of processing over these compounds.