Effect of Freezing Methods on The Quality Characteristics of Tang-yuan

In order to study the effect of different freezing methods on the quality characteristics of Tang-yuan, the experiment adopts three methods by decreased the center of the Tang-yuan to-18℃ of low-temperature refrigerator freezing, spiral tunnel freezing, liquid nitrogen freezing. Beside the rate of water loss, its brightness, transmittance of soup juice, texture properties, pasting properties and sensory evaluation of Tang-yuan were also measured and analyzed. The results showed that there were significant differences in the rate of water loss, the transmittance of soup juice, hardness, springiness, chewiness, paste properties of three freezing methods (p<0.05). The low-temperature refrigerator freezing had the highest rate of water loss, the lowest brightness and transmittance of soup juice, the highest hardness, least springiness, poor chewiness, the highest degree of starch gelatinization and had poor taste of Tang-yuan. The spiral tunnel freezing had higher rate of water loss, lower brightness and transmittance of soup juice, higher hardness, smaller springiness, relatively poor chewiness, higher degree of starch gelatinization and had good taste of Tang-yuan. The liquid nitrogen freezing had the lowest rate of water loss, the highest brightness and transmittance of soup juice, the lowest hardness, the largest springiness, most excellent chewiness, the lowest degree of starch gelatinization, keeping the better quality characteristics of the Tangyuan and had the best taste of Tangyuan. Liquid nitrogen freezing was a freezing method superior to low-temperature refrigerator freezing and spiral tunnel freezing, which could improve the quality characteristics of Tangyuan.