Optimization and Determination of the Physicochemical Properties and Consumer Acceptability of Gluten-Free Noodles Made From Cassava–Bambara Groundnut Composite Flour

Abstract

Noodles made from wheat flour have worldwide popularity because of the ease of preparation and the sensory property. However, recent demands for nutritious and gluten-free foods necessitate the search for alternatives. This study explored alternative ingredients for producing gluten-free noodles using a combined mixture-process design for two components (cassava and Bambara groundnut flours) and process factors (whole egg and xanthan gum). Eight responses were modelled using relevant mixture-process equations based on which the composition of the noodles were optimized using the desirability function. Subsequently, the nutrient content, physicochemical and sensory properties of the optimal noodles were compared with two other formulations to assess the contribution from cassava and Bambara groundnut flours. From the results, the optimal noodles (SA) comprising 70.43% cassava and 29.57% Bambara groundnut flours, 40% whole egg and 0.49% xanthan gum gave the highest desirability index (DI) of 0.82. Comparison of SA with noodles made from 85.06% cassava, 14.64% Bambara groundnut flours of DI, 0.71 (SB) and noodles made from 100% cassava and 0% Bambara groundnut flours of DI, 0.72 (SC), each with 40% whole egg and 0.49% xanthan gum as process variable revealed decreases in the nutrient (g/100 g) (protein, 10.50 ± 0.33; ash, 2.99 ± 0.06; fat, 2.62 ± 0.05), phytochemical (phenolic, 55.39 ± 4.32 mg GAE/g; flavonoids, 0.68 ± 0.03 mg QE/g; tannins, 0.37 ± 0.04 mg/g; antioxidant activity, 145.78 ± 8.42 mg GAE/g) contents and physical properties (browning index, 9.59 ± 0.44; hardness, 68.00 ± 8.19 N; chewiness, 29.32 ± 7.87 N and gumminess, 44.20 ± 5.45 N), whilst the consumer scores for sensory quality and overall acceptability increased when lower levels of Bambara groundnut were used in SB and SC. This shows that Bambara groundnut flour can improve the functionality and nutrient quality, but increasing the content in gluten-free noodles can decrease consumer acceptability.