The multi-scale structures and in vitro digestibility of starches with different crystalline types induced by dielectric barrier discharge plasma

The effects of plasma treatment on multi-scale structures and in vitro digestibility of starches isolated from Tartary buckwheat (TBS), potato (PTS), and pea (PS), were investigated. The results from SEM and CLSM showed that plasma treatment resulted in the extension of pores from the starch hilum to the surface. The XRD and 13C CP/MAS NMR spectra demonstrated that the crystalline type of three starches was not changed by plasma treatment, while the RC and double helix content of TBS increased. Besides, the single helix content and the proportion of amorphous phase decreased following the treatment, which was consistent with the result of SAXS. However, the PTS and PS showed the opposite results by plasma treatment. In addition, the modification significantly changed the molecular weight (Mw) and chain length distribution of all the starches, among which the Mw of PTS fell drastically from 2.45 x 107 g/mol to 1.74 x 107 g/mol. The in vitro digestibility of starches increased significantly when treated with plasma, in which TBS exhibited the biggest increase for its inside-out and side-by-side digestion manners. Therefore, plasma treatment led to different alteration trends for multi-scale structures with quite various change extent for in vitro digestibility about different crystalline starches.