The study conducted by Inge Brouwer of Wageningen University confirms that beta carotene retention in raw food is higher than in cooked food. She took the example of sukuma wiki, a wild plant that is native in Kenya. During 28 hours of storage, the Beta carotene
content of cooked sukuma wiki decreases from about 2.8 mg/100g to 1.6, while in raw food it slows down from 3.5 mg/100g to 2.1. One of the knowledge gaps she raised is how food composition tables especially for processed food can be improved.
This study of sukuma wiki came about with the question of “Can local diets fulfill all nutrient requirements?” This is under the assumption that diet diversity, using locally available, acceptable and affordable food, can fulfill the energy and micro-nutrient needs of people. She concluded that apart from sukuma wiki which is already explored, improvement of diets with locally available food may not fulfill all the nutrient requirements such as iron, calcium and zinc. She cautioned that more information is needed before promoting them.
If you want to learn more about how to identify the nutrients people obtain from their local diets, you can visit this website (http://www.fantaproject.org/tools/optifood