Effect of Freezing and Thawing Treatment on the Quality Characteristics of Taizhou Taro Starch

In order to explore the effects of freezing for 24 h at -18℃, thawing for 1 h at 25℃ treatments (freeze-thaw cycles 0, 5 and 10 cycles) on quality characteristics (starch system properties and microstructure) of taro starch extracted through ammonium medium method were systematically investigated with three different taro as raw materials in this study. The results showed that with the increase of freeze-thaw cycles, the degree of particls surface clamage increased. The quality of stabilization got worse according to the number of freeze-thaw cycles, the following sequence was observed:Jingjiang xiangsha taro > Taixing xianghe taro > Xinghua longxiang taro.The freeze-thaw cycles treatments resulted in the increasing of hardness, elasticity, chewiness of the taro, but the decreasing of cohesiveness.With the increase of freeze-thaw cycles, the onset gelatinization temperature, peak gelatinization temperature and final gelatinization temperature of Xinghua longxiang taro were higher than those of Taixing xianghe taro and Jingjiang xiangsha taro under the same conditions. The swelling powers of the three kinds of taro starch increased with the increase of temperature, the swelling powers and the retrogradation properties of each type of taro starch decreased with the increase of the freeze-thaw cycles.All the results demonstrated that freeze-thaw cycles could lower the quality of samples and this effect was positively related to the number of freeze-thaw cycles.