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|Posted on February 10, 2018 at 1:15 AM|
Legumes are rich sources of proteins, healthy fats, carbohydrates, vitamins, minerals and fiber. They are an excellent sources of β-carotene (provitamin A), thiamine (B1), riboflavin (B2), niacin, pyridoxine (B6), pantothenic acid, folic acid (folacin), ascorbic acid, and vitamin E and K (1). Legumes represent a crucial component of the human diet and their regular consumption is vital for good health.
Legumes are excellent sources of several phytochemicals with proposed health-related benefits (2). Phytochemicals are natural bioactive compounds used for combating free radicals and reducing the oxidative damage responsible by chronic diseases (3). Recent studies have confirmed that cooking methods and various preparation techniques can alter the nutritional quality of food. Hence, understanding the changes which occur in these foods from preparation to table is critical. This is important not just for scientific research, but also for the consumer, who can then prepare and cook legumes in a way which increases their nutritional value (4).
Legumes have been known to contain anti-nutrients such as phytic acid, protease inhibitors and tannins (5). Reducing or eliminating these anti-nutrients is necessary to improve the biological utilisation of legumes. Most anti-nutrients can be reduced or destroyed by using the proper cooking method (5).
Soaking beans prior to cooking is often recommended to decrease the cooking time required. During soaking, the water is dispersed into the starch granules and protein fractions of beans, which facilitate processes, such as gelatinisation and protein denaturation, which soften the texture (6). Adding salt to the soaking water further improves this outcome. Soaking in sodium bicarbonate solution eliminates tannin contents and reduces trypsin inhibitor activity (TIA) in beans (7).
When it comes to cooking methods studies have observed a marked reduction in the content of vitamins when fava beans, lentils and chickpeas were cooked (1). According to the USDA, cooking beans for more than 2 hours, and then frying or baking them can reduce the folate retention by 50%. Beans contain some complex sugars of the raffinose family, and if not broken down by enzymes in the digestive system, can result in gastric issues such as gas production and flatulence. Soaking beans in a salt solution, discarding the soaking solution and cooking with fresh water is the best way to improve the nutritional quality of beans are reduce digestive issues. Many studies have shown that the digestion and absorption of iron can be improved by cooking and heat processing (8 ).
Legumes are an incredibly important source of nutrients in the diet. When prepared correctly anti-nutrients can be significantly reduced and digestive symptoms diminished. Legumes provide an excellent source of fibre, protein and numerous vitamins and minerals. Enjoy legumes as part of your daily diet for optimal health.
1. Prodanov M, Sierra I, Vidal-Valverde C. Influence of soaking and cooking on the thiamin, riboflavin and niacin contents of legumes. Food chemistry. 2004;84(2):271-277.
2. Boccaletti S, Latora V, Moreno Y, Chavez M, Hwang D-U. Complex networks: Structure and dynamics. Physics reports. 2006;424(4-5):175-308.
3. Tiwari U, Cummins E. Factors influencing levels of phytochemicals in selected fruit and vegetables during pre-and post-harvest food processing operations. Food Research International. 2013;50(2):497-506.
4. Fabbri AD, Crosby GA. A review of the impact of preparation and cooking on the nutritional quality of vegetables and legumes. International Journal of Gastronomy and Food Science. 2016;3:2-11.
5. Habiba R. Changes in anti-nutrients, protein solubility, digestibility, and HCl-extractability of ash and phosphorus in vegetable peas as affected by cooking methods. Food chemistry. 2002;77(2):187-192.
6. Siddiq M, Uebersax MA. Dry beans and pulses production and consumption—an overview. Dry Beans and Pulses Production, Processing and Nutrition. 2012:1-22.
7. Taiwo K, Akanbi C, Ajibola O. The effects of soaking and cooking time on the cooking properties of two cowpea varieties. Journal of food engineering. 1997;33(3-4):337-346.
8. Wang N, Hatcher D, Tyler R, Toews R, Gawalko E. Effect of cooking on the composition of beans (Phaseolus vulgaris L.) and chickpeas (Cicer arietinum L.). Food Research International. 2010;43(2):589-594.