| Micronization is a process that can be used to improve the marketability of pulses by reducing their cooking times. It is well accepted that the cooking time of beans is one of their most important quality attributes in addition to size and colour. The present investigation was undertaken to study the effects of pretreatments and micronization on the cookability and the physical chemical properties of both navy and black beans. The physicochemical properties of beans were characterized in terms of the degree of gelatinized starch, the percentage of protein solubility, hardness, firmness, colour, size, physical appearance, apparent density, bulk density, particle density, porosity and water imbibition characteristics. Hardness or the maximum force to compress a set amount (30 g) of cooked beans was used as the cooking quality criterion for assessing the effectiveness of micronization processing pretreatments.; Results from an investigation of operational parameters indicated that the slope of the conveyer bed (SL) and the instrumental setting of a gas-air mixture valve (GL), but not the distance (11–11.4 cm) between the conveyer trough and the infrared radiation source (DL), made significant ( P ≤ 0.05) contributions to the optimization of micronization processing conditions by controlling the rate and extent of the micronization process as evidenced by higher final temperatures and lower moisture contents. Optimum micronization operational conditions occurred at GL = 9 and SL = 5.; Using distilled water to temper the beans, optimum tempering conditions for the micronization of navy and black beans occurred at 28% moisture for 11.5h and 25.8% moisture for 32h, respectively based on the degree of starch gelatinization. (Abstract shortened by UMI.)... |
