关键词: 优质稻, 品质评价, 食味感官评分值, 北方粳稻, 南方粳稻, 籼稻

Abstract:

【Objective】In order to clarify the quality characteristics of high quality japonica rice in north and south China and high quality indica rice, and explore the physical and chemical indexes related to rice taste quality, this study investigated the differences of quality and taste sensory evaluation value of high quality rice in China. It would provide theoretical basis for quality evaluation and improvement of high quality rice varieties in China. 【Method】 A total of 122 high quality rice grain varieties from 30 provinces of China in the third national high-quality rice variety taste quality evaluation activities were used as materials. According to suitable planting area, all the samples were divided into three types as northern japonica, southern japonica and indica rice with the sample numbers of 38, 15 and 69, respectively. To clarify the relationship between physical chemical parameters and taste sensory evaluation value, rice appearance quality, rice flour pasting properties, protein content and taste sensory evaluation value were measured. According to the taste sensory evaluation value, each type of rice was divided into three categories as high (≥90), medium (80-90) and low taste (<80). The differences of rice qualities among different types and taste categories were analyzed. 【Result】Northern japonica rice could be divided into high and medium taste categories. The length-width ratio, protein content, setback viscosity and hardness of high taste category rice were lower than those of medium taste category rice, by 0.2, 0.32 g/100 g, 134 cP, 16 g, respectively (P<0.05). However, the peak viscosity, stickiness and spring value of high taste category rice were higher than those of medium taste category rice, by 145 cP, 70 g and 0.04%, respectively (P<0.05). Southern japonica rice could be divided into high, medium and low taste categories. The chalkiness degree, peak, and breakdown viscosity, and stickiness of high taste category rice were higher than those of low taste category rice, by 0.65%, 314 cP, 259 cP, 261 g, respectively (P<0.05). However, the apparent amylose content, protein content, final and setback viscosity of high taste category rice were lower than those of low taste category rice, by 4.0 g/100 g, 9.2 g/100 g, 260 cP and 574 cP, respectively (P<0.05). Indica rice could be divided into high, medium and low taste categories. The high taste category rice had a longer and thinner grain shape and a better appearance quality than the low taste category rice (P<0.05). The protein content, setback viscosity and hardness of high taste category rice were higher than those of low taste category rice, by 0.45 g/100 g, 157 cP, 46 g, respectively (P<0.05). However, the breakdown viscosity and stickiness of high taste category rice were lower than those of low taste category rice, by 115 cP and 107 g, respectively (P<0.05). 【Conclusion】Northern japonica rice type with high taste sensory evaluation value had a crystal-clear appearance (chalkiness degree was less than 1%), low protein content (about 6 g/100 g), moderate hardness, and high elasticity (about 0.6%). Southern japonica rice type with high taste sensory evaluation value had a good appearance quality, low apparent amylose content (about 13 g/100 g) and setback viscosity (about -250 cP), and high cooked rice stickiness (about -1200 g). Indica rice type with high taste sensory evaluation value had a long and thin grain (length-width ratio about 4.0) and crystal-clear appearance, and low ratio of hardness to stickiness (about 0.25).

Key words: high quality rice, quality evaluation, taste sensory evaluation value, northern japonica rice, southern japonica rice, indica rice