Abstract: This study focuses on the application of Chlamydomonas reinhardtii powder as a novel protein source in noodle products. By multi-scale characterization of changes in the structure and stability of blends of C. reinhardtii powder with medium-gluten flour or whole wheat flour, it aims to elucidate the effect of C. reinhardtii powder on the quality of medium-gluten/whole wheat steamed bun, with the goal of developing C. reinhardtii incorporated steamed bun with both good nutritional balance and eating quality. In the study, C. reinhardtii powder was added at levels of 0%, 2.5%, 5%, 7.5%, and 10% (m/m) to medium-gluten flour (the blends were labeled CM0, CM2.5, CM5, CM7.5, and CM10, respectively) and whole wheat flour (the blends were labeled as CW0, CW2.5, CW5, CW7.5, and CW10, respectively). Each blend was used to make dough. A rapid viscosity analyzer, a farinograph, and an extensograph were used to measure pasting, farinographic, and extensographic properties, respectively. Meanwhile, scanning electron microscopy (SEM) was employed to observe the microstructure of dough, and quality changes in steamed bun were assessed in terms of color, porosity, specific volume, and textural properties. The results showed that the addition of C. reinhardtii powder significantly affected the characteristics of dough and the quality of steamed bun, but its effects on medium-gluten flour and whole wheat flour dough were different. The stability of both doughs decreased, but their extensibility increased. Besides, the specific volume of steamed buns decreased, and their hardness increased. The addition of C. reinhardtii powder had a smaller effect on CM2.5 and CW2.5, while its effect was more pronounced on CM10 and CW10. The farinograph quality index of medium-gluten flour increased and the extensibility energy decreased, while whole wheat flour showed the opposite trend. The effects of C. reinhardtii powder on the quality of medium-gluten and whole wheat steamed bun also differed, with its effect on the specific volume of whole wheat steamed bun being smaller when compared with medium-gluten steamed bun. Therefore, CW2.5 was advantageous for improving both the quality and nutrition of steamed bun. Furthermore, sensory evaluation of CW2.5-based steamed bun showed the highest scores for appearance, aroma, texture, taste, saltiness and overall acceptability, providing important evidence for the feasibility of the commercial application of C. reinhardtii in the food field. In summary, it is fully feasible to develop C. reinhardtii incorporated steamed bun with good nutritional balance, excellent sensory quality, and high market acceptance.

Key words: Chlamydomonas reinhardtii powder; wheat flour; farinograph properties; texture properties; steamed bun