Effects of cooking methods on the iron and zinc contents in cowpea (Vigna unguiculata) to combat nutritional deficiencies in Brazil

Abstract

BackgroundBecause iron deficiency anemia is prevalent in developing countries, determining the levels of iron and zinc in beans, the second most consumed staple food in Brazil, is essential, especially for the low-income people who experience a deficiency of these minerals in their diet.ObjectivesThis study aimed to evaluate the effect of cooking methods by measuring the iron and zinc contents in cowpea cultivars before and after soaking to determine the retention of these minerals.MethodsThe samples were cooked in both regular pans and pressure cookers with and without previous soaking. Mineral analyses were carried out by Spectrometry of Inductively Coupled Plasma (ICP).ResultsThe results showed high contents of iron and zinc in raw samples as well as in cooked ones, with the use of regular pan resulting in greater percentage of iron retention and the use of pressure cooker ensuring higher retention of zinc.ConclusionsThe best retention of iron was found in the BRS Aracê cultivar prepared in a regular pan with previous soaking. This cultivar may be indicated for cultivation and human consumption. The best retention of zinc was found for the BRS Tumucumaque cultivar prepared in a pressure cooker without previous soaking.

Retention of proteins and minerals after cooking in cowpea genotypes1

“…Mota et al (2016) evaluated cooking methods in amaranth, wheat and quinoa, and concluded that estimates of mineral intake should be based on data obtained from cooked foods. Few studies have reported the effect of cooking on protein and mineral contents in cowpea, following the pioneering research of Pereira et al (2014).…”

“…and minerals solubility during immersion and cooking (Bassinello 2009). Pereira et al (2014) evaluated five cowpea cultivars for nutrient retention in normal and pressure cookers, with and without grain immersion, and observed different responses of cultivars, regarding iron and zinc contents after cooking. In another study, Pereira et al (2016) evaluated the bioaccessibility of these nutrients and highlighted the importance of determining the actual percentage of absorption and efficient strategies for low-income populations to have access to foods with high nutritional levels.…”

Genetic diversity of physical, nutritional and functional properties of cowpea grain and relationships among the traits

“…As a legume in general, its protein content is approximately twice that of cereals, and its amino acid (AA) profile, rich in lysine (Lys) and tryptophan (Trp), complements those of cereals, which are rich in sulphurous AAs (Nielsen et al, 1993). Cowpea is also an excellent source of minerals, notably Fe and Zn (Pereira et al, 2014). To overcome insufficient local production of animal protein and its escalating prices and to increase micronutrient (i.e., mineral and vitamin) intakes by malnourished populations, the development of varieties with high nutritional value and the promotion of cowpea consumption are necessary for the people's health in the region, especially among the poor.…”

Modification of local diets to improve vitamin a, iron and protein contents for children aged 6 to 23 months in Kagera, Tanzania

“…Rural farming households lack proper dietary diversity due to limited knowledge and skills on food preparations despite the abundance of micronutrient rich foods in their respective communities [17,18]. This situation was observed in Izimbya ward of Bukoba district.…”

“…We have estimated the nutrient contents of the modified diets. Beans were sorted and washed, placed in saucepan, water was added to immerse beans, then soaked for 8-12 hour, soaking water poured out to reduce phytates [18,33]. Soaked beans were placed in saucepan, and immersed in water, covered with lid and boiled till tender (60 to 90 minutes).…”