Abstract:

On the basis of sensory evaluation of taste quality, the amylose and protein contents in 21 groups of rice
harvested from Tianjin, Heilongjiang and Hainan were analyzed using a conventional method. The results showed that the
sensory score of cooked rice grown in North China ranged from 66.6 to 82.11, while the sensory score of cooked rice grown
in Hainan ranged from 64.23 to 79.99. A significant difference in rice taste quality between the two growing areas was
observed (P ＜ 0.05). The protein content of rice grown in North China was 6.23%–8.99%, compared to 6.78%–11.19%
for those from Hainan indicating a significant difference (P ＜ 0.01). Meanwhile, rice from higher geographic altitude areas
exhibited lower protein content. This result suggests that higher temperature could result in more protein accumulation in
rice. The amylose contents of rice from northern areas and Hainan were 15.39%–19.75% and 14.68%–19.34%, respectively.
The contents of both protein and amylose had a negative correlation with taste quality of cooked rice. Scanning electronic
microscopy showed that the structure of rice endosperm starch granule as well as gelatinization degree of cooked rice was
different in different rice varieties.

Key words: rice, cooking quality, protein starch, scanning electron microscopy (SEM)