Foods contain major and minor components as well as bioactive compounds (e.g. antioxidants, peptides, carbohydrates, lipids, glucosinolates) that are of primary importance for human nutrition. Consequently, their importance has initiated a surge of research and product development in the food industry. In order to adapt to these consumer drivers and enhance the physiological functionality of inherent nutrients, the food industry is developing the so-called “functional foods”.
The latest term was born in Japan. Europe and the American countries incorporated later this concept. The American Dietetic Association (ADA) classified in 2004 all food as functional at some physiological level, pointing out that “the term functional food should not be used to imply that there are good and bad foods“. In addition, it denotes that “all food can be incorporated into a healthful eating plan ─ the key being moderation and variety“. Whole foods like fruits and vegetables represent the simplest example of functional foods since they are rich in bioactive compounds that protect body’s cells against oxidative damage and reduce the risk of developing certain cancers.
It is important to state that functional food must be a food (not a drug), while beneficial effects should be obtained by consuming it in normal amounts within the regular diet. In general, USA prefers the term “nutraceutical”. The latter term refers to any substance, food or part of a food that provides medical or health benefits, including the prevention and treatment of diseases.
The average consumer prefers natural products instead of the chemical ones since people want to take food with the desired health benefits rather than take medicine separately. The increasing demand on functional foods can be explained by the increasing cost of healthcare, the steady increase in life expectancy and the desire of older people for improved quality of their later years. In many cases, it is believed that certain unprocessed or minimally processed foods might have superior health benefits compared to their processed counterparts. Epidemiological studies have shown that health benefits (e.g. reduced risk of coronary heart disease and stroke, diabetes, obesity and cancer) may be attributed to the consumption of both macro- and micro-nutrients. For instance, macromolecules like soluble dietary fibre is known for its ability to lower blood lipid level and at the same time showing advanced gelling properties. Therefore, it can be used to replace fat in foods, stabilize emulsions and improve products’ shelf-life.
Over the last years, new products based on fruit or vegetable and milk have been appeared in the Europe and North American markets. These products have wider consumer acceptance and higher nutritional value, largely due to their higher bioactive compound content and their antioxidant capacity. However, the design and development of functional foods should not only be carried out based on the desired nutritional function. The appearance and sensory properties of foods are very important attributes to the consumer, thus the colour, texture, taste and mouth feel should be taken into account as well. From a manufacturing point of view, the most popular functional food product format is beverages since they are relatively easy to formulate. In the case of soft solid foods, the structure derived quality aspects (e.g. stability, texture and taste) are of high importance for consumer acceptance of foods as well as for the bioavailability of micronutrients. Food manufacturers face a series of technical challenges during fortification of foods with bioactive compounds. For instance, processes should be selected carefully to maintain both functionality of bioactive compounds as well as the quality and sensory attributes of the food.