Abstract: In the current study, water extraction and enzymatic degradation were used to prepare araboxylan (AX) from wheat starch waste water with the aim of evaluating the effects of these two AXs on farinograph property, rheological fermentation characteristics, gelatinization characteristics and water status of wheat dough. The effect of AX addition on the quality of Chinese steamed bread (CSB) was analyzed by scanning electron microscopy and texture profile analysis. The results obtained showed that the purity of the enzymatically produced AX was 86.81%, which was higher than that of the water extractable AX. Both AXs when added at an appropriate concentration could improve farinograph characteristics of wheat dough and the effect of the enzymatically produced AX was more pronounced. A marginal decrease in the degree of gelatinization was observed with the addition of AX. The addition of AX led to a significant decrease in the hardness and chewiness of CSB. Adding the enzymatically produced AX could maintain the integrity of the protein network structure of CSB after compression. But the water extractable AX had a negative impact on the protein network structure of CSB and a large amount of starch granules were exposed when the CSB added with this AX was compressed. The addition of the enzymatically produced AX increased the gas capacity of dough and resulted in more uniform size of gas bubbles in the crumb of CSB, while the water extractable AX destroyed the uniformity of gas bubbles. Xylan endonuclease could improve this negative effect. In summary, multifarious optimization purposes can be achieved by addition of high purity AX to wheat flour-based products.

Key words: wheat starch waste water, arabinoxylan, xylan endonuclease, dough, Chinese steamed bread