Seed treatments affect milling properties and flour quality of black beans (Phaseolus vulgaris L.)

Abstract

Background and objectives Black bean seed contains antinutritional factors that can be reduced or eliminated by seed treatments such as soaking and cooking. This study was carried out to determine the effect of cooked‐dried (cooking for 5–20 min; dried 50°C) and soaked‐dried (soaking for 6–24 hr; dried 50°C) treatments on the physical, milling, and flour qualities of black beans. Findings Feed rate was reduced up to 31% and 25% by cooked‐dried and soaked‐dried treatments, respectively. The decline in feed rate was attributed to increased seed size and decreased seed weight caused by cooked‐dried or soaked‐dried processes. Force needed to fracture the black bean seed decreased for both cooked‐dried and soaked‐dried seeds as treatment time increased. Fine‐particle flour yield declined with seed treatment. Cooked‐dried treatment was found to have the greatest impact on starch damage. However, cooking and soaking had little or no effect on total starch, protein, and ash contents. Conclusions Cooked‐dried and soaked‐dried treatments affected the size, weight, and fracture force of black bean seeds which subsequently affected milling and flour properties. Significance and novelty Limited research has been published, concerning the effect of cooking and soaking pretreatments on milling quality of black beans. Cooked‐dried and soaked‐dried pretreatments caused physical change in grain that must be considered when milling black beans into flour.

Enzyme pre‐milling treatments improved milling performance of chickpeas by targeting mechanisms of seed coat and cotyledon adhesion with various effects on dhal quality

“…At the same time, longer soaking times caused an increase in seed size. An increased seed volume has been reported previously in black beans ( P. vulgaris L.) following a soak‐dry procedure 35 . Only slight structural modifications were observed in cotyledon cell walls of cowpea 36 after soaking at 30 °C, including minor loosening of the cellulose, cell wall thickening and weakening of the pectic middle lamella 36 .…”

“…An increased seed volume has been reported previously in black beans (P. vulgaris L.) following a soak-dry procedure. 35 Only slight structural modifications were observed in cotyledon cell walls of cowpea 36 after soaking at 30 °C, including minor loosening of the cellulose, cell wall thickening and weakening of the pectic middle lamella. 36 It appears that as seeds swell to absorb water during soaking, the increase in cell volume is not completely reversed by subsequent drying, potentially as a result of minor irreversible structural changes to cell walls.…”