Effects of Huangjing polysaccharides on the properties of sweet potato starch

Abstract

Huangjing polysaccharides (HJP) have been shown to have many functions, however little was known about HJP on starch properties. This study investigated the effects of HJP from raw Huangjing (RHJP), high pressure steamed Huangjing (HPSHJP) and nine steamed and nine solarized Huangjing (NNHJP) on the properties of sweet potato starch (SPS). Results showed that HJP reduced setback viscosity (SB) of SPS. HJP decreased hardness, cohesiveness and chewiness, but increased the springiness of SPS gels. RHJP decreased tan δ of the starch gel but HPSHJP and NNHJP were less effective at higher frequencies. HJP increased the solubility but decreased the swelling power of SPS. Starch gel with HJPs showed a denser structure as observed by scanning electron microscopy. HJP decreased the relative crystallinity (RC) of the starch gel where HPSHJP was more effective than RHJP and NNHJP. HJP increased the degree of order (DO) while decreased the degree of double helix (DD) of SPS gels where RHJP was more effective than HPSHJP. Furthermore, HJP decreased the gelatinization enthalpy (ΔH) values of SPS with HPSHJP and NNHJP more effective. In conclusion, HJP could potentially improve the properties of SPS based foods but the changes of HJP after food processing require further investigation.