Nutritional, physico‐chemical, and pasting properties of sweet potato raw powder: effects of color protection combined with different drying methods

Due to the increasing production and significant nutritional benefits of sweet potato, it is crucial to utilize sweet potato as raw powder for various applications. However, there is still a lack of optimum processing technology for the production of sweet potato raw powder with an emphasis on the quality parameters. The present research aimed to improve the quality of sweet potato raw powder by investigating the impact of color protection combined with various drying techniques on the nutritional, physico-chemical, and pasting characteristics thereof. Compared with sun drying alone (O1, P1), the combined treatment of 1% (w/v) ascorbic acid for color protection and microwave vacuum drying (O6, P6) significantly enhanced the nutritional profile of both orange and purple sweet potato raw powders, which increased the content of protein, total dietary fiber, starch, total polyphenols by 9.06-10.82%, 27.25-30.67%, 11.26-13.96%, and 20.52-32.18%, respectively. Furthermore, the resulting powders exhibited superior quality attributes, including color, water absorption index, water solubility index, swelling capacity, and flowability, which were comparable to those of samples prepared by freeze-drying. The findings indicated that ascorbic acid treatment combined with microwave vacuum drying was an effective technique for processing sweet potato raw powder, and it could also be developed on a larger production scale.