Liam Dillow
Caitlin Downs
Nutritional and Health Benefits of Pulses: A Chemistry Perspective
Introduction
A. General Discussion of Benefits of Pulses
Pulses have served as a staple of human diet for thousands of years, and continue to play an important role in agriculture world-wide, particularly in low income populations.[1] Pulses are defined as annual legume crops producing up to 12 grains or seeds.[2] They consist of pea or bean plants, with edible seeds that grow in pods.[3] They come in several varieties and are generally inexpensive.[4] Primary pulses include chick-peas, dry beans, lentils, dry peas, and the flours of pulses.2 Pulse crops can play important roles in cropping systems in achieving soil enrichment through producing nitrogen.2 Their food products are normally consumed after processing, a procedure that involves soaking and can include heating.1 This is done to increase palatability and promote the bioavailability of nutrients, as well as destroy harmful chemicals such as trypsin which naturally occur in some types of pulses.1 Due to their content of indigestible carbohydrates, they are known for causing flatulence; however, there is evidence that this effect can be mitigated by extra rinsing of the food prior to consumption, as well as gradually and consistently increasing dietary intake over time.[5] The major food component of pulses is starch, followed by indigestible fibers and other slow-releasing carbohydrates, and includes significantly high levels of protein (18-25%), nearly twice that contained in grains.1 It is for this reason that pulses can be consumed as a meat alternative, as they contain a significant amount of plant-based protein.4 Data suggest that regular dietary pulse intake significantly reduces LDL cholesterol levels.[6] Pulses contain antioxidants that have been shown to prevent cell damage as well as combat disease and aging.4 They contain significant levels of B-vitamins, iron, folate, calcium, potassium, phosphorous, and zinc, and are generally considered to be a key food in a nutritious diet.4
B. General Discussion of Beneficial Phytochemicals
Phytochemicals are non-nutritive chemical compounds that occur naturally in plants.3 These chemicals act as natural defenses for their host plants and have been shown to afford protective and disease preventing properties for humans upon consumption.[7],[8] Major phenolic compounds in pulses are tannins, phenolic acids, and flavonoids.[9] All of these compounds have antioxidant, anti-inflammatory, and antimicrobial properties.9 Antioxidants provide protection against harmful free radicals in the body.10 Free radicals contain an unpaired electron and localized radicals are highly reactive and damaging to cells.10 Antioxidants neutralize these reactive free radicals by reducing them or by transferring an H atom to them. In the latter case, the reactive localized radicals are replaced by delocalized radicals which are much less reactive and relatively harmless.[10] Pulses also possess isoflavones, saponins, and phytic acid.8 Isoflavones have been shown to reduce osteoporosis, prevent cancer and cardiovascular disease, as well as treat symptoms of menopause.[11] Saponins cause reduction of blood cholesterol by preventing reabsorption, cause programmed cell death in leukemia cancer cells thus inducing mitotic arrest, protect against viruses and bacteria, reduce bone loss, and have antioxidant activity.8 Phytic acid has anticancer and beneficial diabetes effects.8 Phytic acid is the major source of phosphorous in pulses.11
C. Statement of Need and Outline of Approach
Materials and Methods
Results
Discussion
Conclusion
References
1
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([9]) Rebello, C.J.; Greenway, F.L.; Finley, J.W;Whole Grains and Pulses: A Comparison of the Nutritional and Health Benefits. J. Agricult. Food Chem. 2014,62, 7029-7049.
([10]) Barazesh, S. (2008) Probing Question: How do Antioxidants Work? PennState. (accessed February 8, 2016)
([11]) Rochfort, S.; Panozzo, J. Phytochemicals for Health, the Role of Pulses. J.Agricult.Food Chem. 2007, 55, 7981-7994.