Enhancement of the phytonutrient content of a gluten-free soup using a composite of vegetables

Abstract

The demand for instant nutritious functional foods has been on the rise, due to the increase in the incidence of lifestyle diseases. A dried phytochemical-rich instant soup, developed using a variety of vegetables, may be an attractive food for health-conscious consumers. Therefore, this study aimed at using response surface methodology to develop an instant vegetable soup rich in fiber and phytochemicals, whilst with reduced salt. The independent variables were a green leafy vegetable cocktail, sweet potato flour and pumpkin flour; and the dependent variables were total phenolics and the color of the soup. The soup was acceptable, with an improved in-vitro antioxidant activity, increased β- carotene content, 18 g fiber, 7.74 g proteins, 51.73 g carbohydrates and 1.3 g sodium per 100 g soup powder. The major flavonoid in the soup was catechin, whilst the phenolic acids; ferulic acid, caffeic acid, ellagic acid and luteolin were present in relatively high amounts in the soup. Ellagic acid content in soup was similar to that of strawberry, whilst caffeic acid was lower than levels noted in apples. The developed soup with different vegetables can be of benefit with various phenolic compounds and other phytonutrients.