Effect of nitrogen fertilizer application rate on the eating characteristic and textural properties of japonica softer rice

【Objectives】 The objective of this study was to clarify the response to nitrogen levels in the eating quality and textural characteristic of different rice cultivars and the relationship between the tasty and texture related indexes.【Methods】 A field experiment was carried out with two japonica softer rice varieties. Four nitrogen application levels were designed: 0, 150, 225, and 300 kg/ha, and the eating qualities and mouthfeel of japonica softer rice were measured and their relationships with each other were calculated. 【Results】 1)With the increment of nitrogen input levels, the aroma, gloss, taste, mouthfeel and comprehensive indices were decreased but the integrity increased, the CV% of eating indexes was in order of mouthfeel gloss taste value taste aroma integrity; indicating that nitrogen levels affect mouthfeel and gloss more than aroma and integrity of rice. 2)With the increment of nitrogen levels, the hardness, cohesiveness, chewiness and resilience were increased at first and then decreased, the maximum value appeared at 225 kg/ha treatment; the adhesiveness of rice exhibited opposite trend, the minimum value appeared at 225 kg/ha treatment, springiness was not influenced by nitrogen fertilizer. The CV% of rice textural properties was in order of chewinesshardnessresilienceadhesivenesscohesiveness, indicating that nitrogen levels affect the chewiness and hardness more than cohesiveness. 3) The values of aroma, gloss, taste, mouthfeel and comprehensive indexes of cultivar Nanjing9108 was higher than those of Nanjing5055, but the integrity was opposite. The coefficient of variation of taste indexes of Nanjing9108 were higher than Nanjing5055,indicating the better eating qualities of Nanjing 9108 than Nanjing5055. Nanjing 9108 was more sensitive to nitrogen fertilizer than Nanjing5055. 4)The values of hardness, adhesiveness, springiness, cohesiveness of Nanjing 9108 were lower than those of Nanjing5055, but the adhesiveness was opposite. 5)The aroma was positively correlated with aroma, gloss, taste and mouthfeel, negatively with integrity; hardness was significantly negatively correlated with cohesiveness and chewiness; resilience was negatively correlated with adhesiveness and springiness. 【Conclusions】 Nitrogen levels significantly impacted the eating quality and textural properties of japonica soft rice. Nanjing 9108 was more sensitive to nitrogen fertilizer than Nanjing5055, N fertilization decreased the taste, aroma, mouthfeel, but increased the integrity of the selected two rice cultivars. When the N application levels were lower than 225 kg/ha, the N fertilization increased the chewiness, hardness, resilience and adhesiveness of the rice. Therefore, N application levels should be considered carefully for keeping the good tasty quality of japonica softer rice.