Changes in levels of enzyme inhibitors during soaking and cooking for pulses available in Canada

Abstract

The effects of processing (soaking and cooking) on enzyme inhibitors (a-amylase, trypsin and chymotrypsin inhibitors) in a range of pulses (4 peas, 9 lentils, 3 chickpeas, 2 faba beans and 4 beans) were investigated, using soybean as a control. Analysis of variance indicated that pulse type, treatment and their interaction had significant effects on levels of all enzyme inhibitors. Soybean contained the highest levels of trypsin inhibitory activity (TIA) and chymotrypsin inhibitory activity (CIA) among all seeds. a-Amylase inhibitory activity was absent from peas, lentils, chickpeas and faba beans, but was present in beans and soybean. TIA was found to be low in peas but high in beans. Beans contained relatively high CIA levels followed by chickpeas, lentils, peas and faba beans. Soaking markedly decreased the activity of enzyme inhibitors. Cooking of presoaked seeds was even more effective as greater reductions (78.7-100%) were observed for all pulses. The content of enzyme inhibitors in pulses varied widely, but levels of protease inhibitors were generally lower that those found in soybean. Processing, in particular heat treatments, drastically reduced these levels.

Nutritional properties of pea protein‐enriched flour treated with different proteases to varying degrees of hydrolysis

“…Trypsin inhibitor activity (TIA) decreased from 38.4 to 12.8 TIU/mg overall, whereas chymotrypsin inhibitor activity (CIA) had a larger magnitude of reduction, decreasing from 63.9 to 5.6 CIU/mg ( Table 2). Levels of both enzyme inhibitors in the untreated PPEF were higher than values reported in literature for raw peas [1.3-4.92 TIU/mg; 2.84-3.34 CIU/ mg] (Shi, Mu, Arntfield, & Nickerson, 2017;Wang, Hatcher, & Gawalko, 2008). However, comparing flour to whole seeds, PPEF had a higher protein content which was almost double that of whole seeds.…”

“…Similar to the phenolics and condensed tannins, the protease inhibitors may have leached into the solvent during PPEF dispersion which was then drained off and removed after the hydrolysis process. Shi et al () reported that soaking decreased both trypsin and chymotrypsin inhibitors in various Canadian pulses, including peas, whereas cooking completely removed CIA and decreased TIA to very low levels due to the heat‐labile nature of these proteins. Clemente et al () found a significant reduction in TIA (80% of the initial activity) in chickpea protein hydrolysates modified with either Alcalase or Flavourzyme, or both, to DH levels of 27% and >50%, respectively.…”

Inactivation Methods of Trypsin Inhibitor in Legumes: A Review

“…The soaking process itself improved TI inactivation compared with only cooking likely due to the leaching of TIs into the steep water and also it improved the decrease of other antinutritional factors, such as lectin. Nevertheless, soaking also promoted loss of minerals in about 25% (Pedrosa and others ; Shi and others ).…”

Influence of Different Cowpea (<i>Vigna unguiculata</i> (L.) Walp.) Genotypes from Burkina Faso on Proteases Inhibition

“…The role of chymotrypsin inhibitors is similar to trypsin inhibitors in that they limit protein digestibility. However, the site of activity is different in that chymotrypsin targets hydrophobic residues such as tyrosine, tryptophan and phenylalanine rather than lysine and arginine [20]. Many protease inhibitors (trypsin and chymotrypsin inhibitors) are already isolated from plants seeds.…”

“…In contrast, trypsin and chymotrypsin inhibitors could be linked to health-promoting properties. Protease inhibitors can act as anticarcinogenic agents [14,20], act at many steps of the HIV lifecycle [26]. The TI of peas significantly inhibited human colon adenocarcinoma cells proliferation with an IC50 value of less than 50 µM [14,26].…”