†Laboratory of Food Chemistry, Wageningen University, Post Office Box 17, 6700 AA Wageningen, Netherlands.
‡School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China.
J Agric Food Chem. 2015 May 13;63(18):4646-54. doi: 10.1021/jf506349w. Epub 2015 May 4.
Sweet potato starch was modified by cross-linking, hydroxypropylation, and combined cross-linking and hydroxypropylation, and the starches were subsequently sieved to obtain differently sized granule fractions. The effects of granule size of native and modified sweet potato starch fractions and all fractions were investigated with respect to their physicochemical properties. The large-size granule fraction (27-30 μm) showed a 16-20% higher chemical phosphorylation and a 4-7% higher hydroxypropylation than the small-size granule fraction (14-16 μm). The large-size granule fractions of native and modified sweet potato starches showed lower transition temperatures (0.7-3.1 °C for peak temperature of gelatinization) and lower enthalpy changes (0.6-1.9 J/g) during gelatinization than the small-size granule fractions, making the sweet potato starch different from cereal starches. The large-size granule fraction of native starch showed a higher paste viscosity (78-244 cP) than the corresponding small-size granule fraction. In addition, cross-linking and hydroxypropylation affected the paste viscosity of the large-size granule fraction significantly more than that of the small-size granule fraction when compared to the corresponding parental starch fractions. The large-size granule fraction of native and dual-modified starches showed a lower syneresis after freeze-thaw treatments than the small-size granule fractions. The difference in swelling power between large- and small-size granule fractions was not significant. In general, the large-size granule fraction of sweet potato starch was more susceptible for cross-linking and hydroxypropylation and the physicochemical properties were changed to a higher extent compared to the corresponding small-size granule fraction.
红薯淀粉经过交联、羟丙基化和交联与羟丙基化结合的改性处理，然后通过筛分获得不同粒径的颗粒级分。研究了原淀粉和改性淀粉的不同粒径颗粒级分以及所有级分的物理化学性质。与小粒径颗粒级分（14-16μm）相比，大粒径颗粒级分（27-30μm）的化学磷酸化程度高 16-20%，羟丙基化程度高 4-7%。原淀粉和改性红薯淀粉的大粒径颗粒级分的糊化起始温度（峰值温度）和焓变（0.6-1.9 J/g）均低于小粒径颗粒级分，使红薯淀粉与谷物淀粉不同。原淀粉的大粒径颗粒级分的糊化黏度（78-244 cP）高于相应的小粒径颗粒级分。此外，与相应的原始淀粉级分相比，交联和羟丙基化对大粒径颗粒级分的糊化黏度的影响比对小粒径颗粒级分的影响更大。与小粒径颗粒级分相比，原淀粉和双改性淀粉的大粒径颗粒级分在冻融处理后表现出较低的析水率。大粒径和小粒径颗粒级分之间的膨胀力差异不显著。一般来说，与相应的小粒径颗粒级分相比，红薯淀粉的大粒径颗粒级分更容易发生交联和羟丙基化，其物理化学性质的变化程度更高。
