Investigation of the effects and mechanism of incorporation of cross-linked/acetylated tapioca starches on the gel properties and in vitro digestibility of kung-wan

The effects and mechanism of incorporation of cross-linked tapioca starch (CTS) or acetylated tapioca starch (ATS) on the gel properties and in vitro digestibility of kung-wan (a Chinese-style meatball) were evaluated. The results indicated that incorporation of either CTS or ATS significantly enhanced the gel properties of kung-wan in a dose-dependent manner (P < 0.05), as well as the rheological properties of meat batter. Moreover, hydrogen bonds and electrostatic interaction were the major intermolecular forces in kung-wan when incorporated with CTS or ATS. Meanwhile, CTS and ATS acted as fillers in the meat protein gel matrix, which was further verified by the microstructure of kung-wan. However, CTS produced a more uniform and dense meat protein gel network than ATS, which was mainly due to its limited swelling characteristics. In addition, the incorporation of CTS or ATS significantly increased the in vitro digestibility of protein in kung-wan with increasing level of addition (P < 0.05). However, no significant differences in protein digestibility were detected between the CTS and ATS groups at the same addition level (P > 0.05). Our results provided some critical points for the actual application of modified tapioca starch to promote the quality profiles of kung-wan.