Project Abstract: Assessing the anti-nutritional properties of Canadian pulses
This project involves quantifying the levels of antinutritional compounds within a wide range of Canadian pulses and soybean (as a control) found as-is within the marketplace and after soaking/cooking using colourimetric and chromatographic assays. Work is being done through a colloborative research partnership between the University of Saskatchewan, the University of Manitoba and AAFC-Saskatoon.
The effects of legume type and processing (soaking and cooking) on enzyme inhibitors (α-amylase, trypsin and chymotrypsin inhibitors), lectins, phytic acid, total and soluble oxalates, total phenolics and total tannins in a wide range of Canadian pulses (4 peas, 9 lentils, 3 chickpeas, 2 fava beans and 4 beans) are being investigated, using soybean as a control. Within the final year of the project, data was collected for phytic acid, oligosaccharides and, vicine and convicine level in raw and cooked (boiling in 95oC water, for 1 h) pulses.
The vicine and convicine contents of whole and split fava beans were found to be similar with levels of 7.3-7.4 mg/g and 3.1-3.3 mg/g, respectively, which then declined to 4.6-5.4 mg/g and 2.1-2.4 mg/g, respectively upon cooking implying heat sensitivity of the compounds. Phytic acid levels within the raw and cooked pulses ranged between 0-2.1% and 0.7-2.5%, respectively. The levels in the vast majority of pulses remained unchanged by cooking suggesting phytic acid is relatively insensitive to heat. However, depending on the sample, some pulse samples increased slightly, whereas others declined. Oligosaccharide concentrations were measured for all pulses, in terms of their content in sucrose, maltose, raffinose, circeritol, stachyose and verbascose levels. Overall the impact of cooking resulted in a decline in most oligosaccharides. However, in some instances levels remained the same or in some cases increased, depending on the pulse and the particular oligosaccharide being examined. Results suggest that cooking was an effective method at reducing the levels of some oligosaccharides.
To summarize, the level of anti-nutritional factors in Canadian pulses varied widely, but levels were generally lower that those found in soybean. Processing, specifically heat processing, significantly reduced these levels.
For more information, contact Dr. Michael Nickerson (306) 966-5030