The consumption of vegetables in Mexico includes a wide variety of plants that grow naturally as weeds in the fields. The intake of these vegetables is very important in the Mexican diet because these plants supply an important input of nutrients and compounds such as fiber, vitamins, minerals, and antioxidants. Thus, the plants may be universally promoted as healthy. However, there is little information about these vegetables of popular consumption, especially in terms of the nutritional changes caused by boiling. To determine the influence of boiling on five plants of popular consumption in Mexico, the nutritional composition (proximal analysis, dietary fiber, and oxalates), antioxidant compounds (ascorbic acid, phenolics), antioxidant activity (measured by ABTS and DPPH assays), and physicochemical characteristics (water retention capacity, viscosity, color, and SEM) were evaluated. The boiling affected the nutritional composition of plants, mainly soluble compounds as carbohydrates (sugars and soluble fiber), ash, ascorbic acid, and phenolic compounds and caused changes in food hydration and color. Therefore, it is recommended that these plants be consumed raw or with short boiling times and included the cooking water in other preparations to take advantage of the nutrients released in the food matrix. In the future, to complete studies, 3 to 5 min of cooking should be considered to minimize undesirable modifications in terms of the vegetables’ composition.
The edible plants studied had an appreciable content of dietary fiber, ashes, ascorbic acid, phenolic compounds, and a good antioxidant capacity. However, boiling for 3 to 5 min caused the loss of soluble compounds (sugars, soluble fiber, ash, ascorbic acid, and phenolic compounds), and affected the color, hydration properties, and cell integrity. Hence, it is important to recommend the use of boiling water of vegetables in other food preparations to take advantage of the released soluble compounds. Due to the study of a food could be overvalued when only data of raw product are studied, it is important to consider short periods of heat treatment of leafy vegetables in future studies to reduce the nutrient losses without affecting its sensory acceptance.