Processing methods for reducing alpha-galactosides in pulses

Abstract

Pulses are an excellent source of protein and dietary fiber and are consumed around the world. Their consumption has been recommended as part of a healthy diet. However, they contain various antinutrients such as tannins and trypsin inhibitors, as well as indigestible carbohydrates called alpha-galactosides. These oligosaccharides are fermented by the microorganisms in the gut, producing gas and causing flatulence in healthy individuals. While this flatulence is undesirable (and results in their low acceptance in the Western diet), alpha-galactosides have also been hypothesized to increase susceptibility to bowel diseases, and their presence in the gut worsens the symptoms of patients with irritable bowel syndrome. The elimination of alpha-galactosides by breeding is difficult as they play a vital role in maintaining seed viability through periods of drought and cold. There is a critical need to evaluate the various post-harvest processing methods, and their effect on alpha-galactoside removal to facilitate commercialization. This paper reviews the effectiveness of methods and processing conditions in alpha-galactoside removal from a variety of pulses.

Autoclaving and extrusion improve the functional properties and chemical composition of black bean carbohydrate extracts

“…Despite the fact that there were no changes in the content of α‐GOS among the CE, the concentration was lower (0.03 to 0.66 g of α‐GOS/100 g of CE) compared to literature reports for common raw beans (3.3 g of α‐GOS/100 g beans) (Escobedo, Mora, & Mojica, 2019) The reduction of α‐GOS in the CE is not associated with the thermal process used, but it could be due to the carbohydrate extraction process, which includes solubilization and precipitation steps. The α‐GOS could remain in the aqueous phase with the solubilized proteins during this process because of their high solubility (Thirunathan & Manickavasagan, 2018). In contrast, the thermomechanical process of extrusion treatment could contribute to the reduction of α‐GOS in the extruded bean CE.…”

Thermal and enzymatic treatments reduced α‐galactooligosaccharides in common bean ( Phaseolus vulgaris L.) flour

“…The soaking process using 1% NaHCO 3 solution increases the permeability of the coat and cotyledon, compared to distilled water, probably due to a mechanism of ion exchange or chelation. Resulting in a higher loss of sugars, including these galactosides, by diffusion into the soaking or cooking water (Mubaiwa, Fogliano, Chidewe, & Linnemann, ; Shimelis & Rakshit, ; Thirunathan & Manickavasagan, ).…”

“…The soaking process using 1% NaHCO 3 solution increases the permeability of the coat and cotyledon, compared to distilled water, probably due to a mechanism of ion exchange or chelation. Resulting in a higher loss of sugars, including these galactosides, by diffusion into the soaking or cooking water (Mubaiwa, Fogliano, Chidewe, & Linnemann, 2019;Shimelis & Rakshit, 2007;Thirunathan & Manickavasagan, 2018 Regarding the tannins content, the common beans treated with bSEf showed more effective results (p < .05) compared to thermal processes, with a reduction on tannins content by 81.5% and 79.9%, for black and pinto beans, respectively ( Figure 3C,D). The enzyme complex could also have a hydrolyzing effect on tannins.…”

“…Khattab and Arntfield (2009) also observed a reduction of 36.7% in beans that were soaked in water for 18 hr. The solubility of these compounds and the diffusion rate are the main factors that may cause these losses of galactosides during soaking (Thirunathan & Manickavasagan, 2018).…”

“…Limiting the intake of α-GOS has been shown to improve these symptoms (Prince et al, 2016;Suárez-Martínez et al, 2016;Takagi et al, 2016). Enzymes such as α-galactosidases have been used to eliminate the α-GOS concentration from common beans with promising outcomes; however, their high cost limits their use on industrial applications (Thirunathan & Manickavasagan, 2018). Furthermore, commercial enzyme blends lacking α-galactosidase may have a side activity on the α-GOS, which could be a more profitable opportunity.…”