Effect of adding wheat (Triticum aestivum L.) farina with varied integrity of endosperm cell wall on dough characteristics, dried noodles quality and starch digestibility.

The changes of intact endosperm cell wall in cereal food processing and its effect on starch digestibility are important for developing nutritious and healthy next generation foods, but their changes in the process of traditional Chinese cooking products such as noodles making have not been investigated. In this paper, the changes in endosperm cell wall in the process of making dried noodles by adding 60 % wheat farina with varied particle sizes were tracked, and the underlying mechanisms affecting the noodle quality and starch digestibility were revealed. With increasing particle size (150-800 μm) of farina, the contents of starch and protein, swelling index of glutenin, and sedimentation value decreased significantly and the dietary fiber increased sharply; moreover, water absorption, stability and extensibility of dough decline obviously while the resistance to extension and thermal stability were enhanced. In addition, noodles made with flour added larger-particle size farina had a lower hardness, springiness, and stretchability while a higher adhesiveness. Compared to the flour and other samples, the flour with the smaller-particle size farina (150-355 μm) showed better rheological properties of dough and cooking quality of noodles. Furthermore, the integrity of the endosperm cell wall increased with increasing particle size (150-800 μm), which was perfectly preserved during noodle processing and was an effective physical barrier to inhibit starch digestion. The starch digestibility of noodles made from mixed farina with low protein content (∼15 %) did not significantly reduce compared to that of wheat flour noodles with high protein content (∼18 %), probably due to the increased cell wall permeability of noodle processing, or the overwhelming effect of noodle structure or protein content. In conclusion, our findings will contribute to an innovative perspective for in-depth understanding of the impact of endosperm cell wall on the quality and nutrition of noodles at the cellular level, which provided a theoretical basis for the moderate processing of wheat flour and the development of healthier wheat-based food products.