Abstract:
Paddy is one of the main food crops in many countries. It is usually produced into rice and traditional rice products such as rice noodles (rice-flour noodles) that are popular in the south of China, such as Hunan and Guangdong province. However, rice and rice noodles (rice-flour noodles) made from rice at different degrees of aging have different tastes. To explore the changes of edible qualities of rice and rice noodles during the aging of paddy, and to find the best way of eating paddy with different aging degrees, an artificial climate box was used to simulate the temperature and humidity of the typical high-temperature and high-humidity (35℃,
RH 75%) storage ecological area to accelerate the aging of rice. The paddy was stored for 12 months, and samples were taken out every month, weighed, washed, and steamed to make rice. After rice hulling, rice milling, and steaming, the rice was made into rice noodles. The cooking and texture characteristics of rice and rice noodles were measured and their eating quality was determined by sensory evaluation of, and the effect of accelerated aging on the changes of various indexes was studied. The results showed that with the extension of storage time, both the dry matter of rice soup and the pH value showed a downward trend, indicating that the taste and smell of rice began to deteriorate and the taste became sour. The iodine blue value of rice soup also decreased. The decline throughout the storage period indicated that the soluble amylose content in the rice grains gradually decreased. The water absorption of rice noodles showed an upward trend from the 2th to 10th month of storage, indicating that the taste of rice noodles began to become soft and waxy, and it began to decrease from the 10th to 12th month, indicating that the taste of rice noodles began to harden. The turbidity of the powder soup showed an upward trend in the first 3 months of storage, and in the following 4th to 12th month, an overall downward trend was observed; both the cooking loss rate and the cooked section rate dropped sharply in the first 4 months of storage, indicating that the cooking resistance of rice noodles was improved and remained stable in the later storage period. In the study of texture properties, as the storage time increases, the hardness of rice continued to increase, and the viscosity and elasticity continued to decrease; the hardness and chewiness of rice noodles continued to increase, and the viscosity continued to decrease. In the sensory evaluation test, the sensory score of rice continued to decline with the prolonged storage time, and the sensory score of rice noodles began to decline after reaching the maximum value at the 8th month. In general, with the extension of storage time, the palatability of rice continued to decline, while the palatability of rice noodles showed a trend of increasing first and then decreasing. Therefore, rice made from newly harvested paddy will have better edible quality, and rice noodles with better edible quality can be made from paddy stored for a certain period of time.