Effect of processing, formula and measurement variables on alkaline noodle color - Toward an optimized laboratory system

A standardized laboratory method for assessing the color potential of flours for yellow alkaline (Cantonese) noodles is needed, especially for evaluating large numbers of small-scale samples such as found in wheat breeding populations. To develop such a method, a number of processing and formula parameters were varied and judged for optimum level based on 1) discrimination and mean separation of flours, 2) sensitivity to minor variation in the protocol parameter, 3) practicality and simplicity for the technician, and 4) time efficiency. Four flours milled from single-cultivar grain lots representing two with good and two with poor color potential were made into alkaline noodle sheets varying in thickness of 0.75-2.00 mm, water absorption of 33.0-39.0%, mixing time of 2-6 min, and NaCl levels of 0-4% tall flour weight basis). Commission Internationale de l'Eclairage (CIE) tristimulus color space (L*, a* b*) values were measured at 0-24 hr using white, yellow, and black background tiles. Noodle sheet side and a dough resting period were examined. The flours themselves were a consistently large, significant source of variation for color, especially lightness (L*). Based on the optimization criteria, a noodle sheet thickness of 1.5-2.0 mm, an optimum to slightly over optimum water absorption (36% for the flours in this study) with some adjustment for protein content and dough handling properties, a mixing time of 4 min, no dough resting period, and 2% NaCl were selected. Color measurement at 24 hr on a white or otherwise light-colored background tile was judged best using a consistent side of the noodle sheet. Resting doughs for 1 hr slightly improved handling and sheeting characteristics but was not included for time efficiencies.