**1.1 What are functional foods?**

Functional foods are such types of foods that are highly nutritious and have a potential health benefits besides their basic nutritional values. Functional foods contain either supplements or other additional ingredients designed to improve the health of the general population. Foods are being examined and improved which may reduce chronic disease risk and optimize health. Japanese has first developed the concept of functional foods in 1980. At that time, their health care costs were escalating and the Ministry of Health and Welfare initiated to approve some foods which were documented with their health benefits and used for improving the health of the aging population [1].

#### **1.2 Functional food components**

Functional food components are bioactive compounds used in the manufacture of functional foods. They are potentially beneficial compounds found either naturally in foods or added to them as functional ingredients. The functional food components are carotenoids, isothiocyanates, dietary fiber, phenolic acids, fatty acids, plant stanols and sterols, flavonoids, polyols, soy protein, prebiotics and probiotics, phytoestrogens, vitamins, and minerals. Research-based evidence suggested that there is a relationship between functional food components, health, and well-being [2]. Therefore, functional food components can be used in the treatment and prevention of diseases, as they have health-promoting roles at various stages of disease control. Phytochemicals are plant-derived, non-nutritive, and biologically active functional food components that function in the body to prevent certain non-communicable diseases [3]. About 900 phytochemicals are found in foods and 120 g of foods or vegetables may have around 100 different types of phytochemicals [4]. The earlier concept was that functional food components occur mainly in plant foods, such as whole grain, fruits, and vegetables. However, functional food components are also found in animal products; these are milk, fermented milk products, and cold-water fish. These animal source food components are probiotics, prebiotics, symbiotic, conjugated linolenic acid, long-chain omega-3, -6, and -9 polyunsaturated fatty acids, etc.

#### **1.3 Production of functional foods**

Functional foods can be made by different approaches, such as (1) eliminating harmful components from the food (e.g. allergic protein), (2) increasing the concentration of a component in the food by fortification with micronutrients or any other ingredient, (3) eliminating excessive component mainly a macronutrient like fats and producing a beneficial component such as chicory inulin, (4) increasing stability or bioavailability of a component to produce a functional effect or to reduce the disease risk, and (5) adding a new component in the foods which has the beneficial effect, e.g. antioxidant.

In this chapter, functional food ingredients, including their sources and physiological functions, are discussed.
