Food diversity is defined as the availability of diverse foodstuff in your meal in order to get the maximum nutritional benefits. The food source may be plants and animals available within the ecosystem. Food biodiversity can be measured from the production and consumption of available foodstuff. Healthy food diversity has been developing in many countries.
Vegetables are the parts of plants that consist of roots, stems, and leaves and consumed by humans and other animals as food. The vegetable is the prime component of food diversity and popular due to its health benefits and nutritional value. Green leafy vegetables contain a lot of minerals and vitamins contain phenolic which can act as antioxidants. The consumption of vegetables protects the human body from chronic diseases including cardiovascular disease, some cancers, and immune dysfunction. Vegetables as a source of antioxidants enhance the immunity of the body to fight against free radicals. Without the intake of necessary vegetables, these free radicals can spread and eventually lead to various types of cancer and other body illnesses.
Cooking is a common process of making edible and safe food by applying heat and makes them ready for consumption. Many techniques and ingredients have been used for cooking throughout the world. Cooking may be baking in various types of ovens, grilling food over an open fire to using electric stoves reflecting unique environmental and cultural traditions and trends. However, Heat treatments like steaming boiling and stir-frying are common cooking methods in Indonesia. These cooking methods may impose detrimental changes to the food e-g changes in some components of protein fraction and the loss of nutrients due to lipid oxidation. Syukri et al. (2018) informed that chlorophyll is an indicator for the level of freshness of green vegetables. Anggraini et al. (2019) and Cheynier (2012) studied that phenolic is a group of plant secondary metabolites that indicated the quality of plant-based foods and responsible to maintain color characteristics and flavor properties of plants. The cooking method especially stir-frying induced a higher level of total phenolic contents.
A research has been carried out by the Azima et al. (2020) and published in Pakistan Journal of Nutrition in order to investigate the changes of nutrient such as phenolics, vitamin C, and minerals in green leafy vegetables after cooking by three heat treatments methods that are widely used in Indonesia. The team of researchers found that the stir-frying and boiling cooking methods have found to be the best for healthy ingestion of treated green leafy vegetables.