Relationships between fatty acids of grain and taste quality of rice and regulating effects of soil moisture

To prove the relationships between the taste quality and fatty acids content of rice grain, fatty acids, protein, amlose contents of five varieties of rice were measured. And soil moisture was regulated at water poteintial of -30 ~ -35 kPa and -60 ~ -65 kPa, then the ingredients and taste value of superior grain, medium grain and inferior grain of two varieties were analyzed. The results show that fatty acids content of “Kenjiandao 5”, “Fushiguang” and “DongnongV 10” is significantly higher (P<0.01) than that of “Kendao 8” and “Kongyu 131”. Also the taste value of “Kongyu 131” is significantly higher than that of “DongnongV 10”, “Kenjiandao 5” and “Kendao 8”. Furthermore, “Fushiguang”, “DongnongV 10” and “Kenjiandao 5” have a significantly higher taste value than “Kendao 8”; and the taste value of “Fushiguang” is significantly higher than that of “DongnongV 10” and “Kenjiandao 5”. Taste value is significantly negatively correlated with fatty acids and protein contents (r = -0.577^**, -0.910^** for 2002; r = -0.845^**, -0.980^** for 2003). Protein content is in turn significantly positively correlated with fatty acids content (r = 0.582^** for 2002; r = 0.866^** following order of fatty acids > protein > amylose. Fatty acids content of the “Shangyu 397” and “Suijing 3” rice grains at different positions of the panicle are significantly higher (P< 0.01) than in the control under different water-control treatments before heading. This is, however not the case for “Suijing 3” under high water-control treatment at tilling stage. During the same growth period under intensive water-control, fatty acids content of the two varieties is higher, but it is not significant. Water-control during filling stage leads to a significantly lower taste value compared with CK. The coefficient of variance for fatty acids is higher than those for protein and amlyose. However, protein path coefficient is the highest among the grain ingredients. In summary therefore, rice grain fatty acid content subject to external influences is highly correlated with taste quality. It then implies that fatty acids study should be part of any grain taste evaluation and nutritional assessments.