Abstract:

Noodle color is one of the most important determinate factors for noodle quality. For Chinese consumers, the best noodle color is bright creamy white with absence of discoloration. Noodle color depends on several factors such as intrinsic flour color, ash content, flour extraction, and flour particle size and protein concentration. Some instrumental methods have been developed for determining noodle quality and evaluating the sensory characteristics of the noodle products. Nitrogen application could affect wheat yield and the end-use quality. Previous studies mainly focused on the effect of nitrogen fertilizer on protein content, bread making quality. To evaluate the effects of nitrogen application rate on flour, noodle color and noodle texture, we used two wheat cultivars Yumai 49-198 and Lankao Aizao 8 in field experiments on the Henan Agricultural University Research Farm in 2004–2005 and 2005–2006 growing seasons. The soil contained 17.8 g kg^-1 organic matter and 0.99 g kg^-1 total N. Prior to sowing, fertilizers of P₂O₅ 150 kg ha^-1and K₂O 150 kg ha^-1 were applied. Three treatments of nitrogen were 0 (N1), 180 (N2), and 360 kg ha^-1 (N3), respectively. Fifty percent of the nitrogen was for basic application before sowing and the left 50% was applied at elongation stage. The experiments were arranged in split plot design with three replicates. The results indicated that both in Yumai 49-198 and Lankao Aizao 8, as nitrogen application rate increased, color grade value (CGV), redness (a*), yellowness (b*) of flour and paste increased while brightness (L*) declined. The lowest value of L* was obtained in the treatment of N3, and the highest values of a* and b* were observed in the treatment of N2. The CGV, a*, and b* values of noodle sheet increased, while L* value decreased with the elongation of rest time. The texture analysis showed that hardness, gumminess and chewiness enhanced with the increase of nitrogen rate. For these parameters, the highest values were observed in treatments of N3 in both wheat cultivars. The results also indicated that texture traits can be used to evaluate noodle sensory characteristics.

Key words: Nitrogen application rate, Flour color, Noodle quality, Winter wheat (Triticum aestivum)