稻谷储存过程中食味品质对氮肥的响应

Response of rice taste quality to nitrogen fertilizer during storage

【目的】明确氮肥水平和储存时间与稻米食味品质的关系,为优质稻米的实际生产和储存提供理论依据。【方法】以高产优质水稻品种德优4727(低氮高效型)和旌优781(低氮低效型)为供试材料,设4个氮肥水平处理,分别为0 kg/ha(N0)、90 kg/ha(N1)、150 kg/ha(N2)和270 kg/ha(N3),测定不同氮肥水平下稻谷产量及其在储存3个月和12个月后蛋白含量、直链淀粉含量和淀粉黏滞性等食味品质的变化情况,并分析储存时间与蒸煮食味品质各指标的相关性。【结果】德优4727和旌优781的产量、蛋白含量和直链淀粉含量均随施氮量增加而升高,N2处理的产量增幅最大,分别为31.63%和28.86%,N3处理的蛋白和直链淀粉含量增幅大于其他3个处理,而食味值最低。储存12个月后,N3处理的蒸煮食味品质较其他处理差。氮肥水平与稻米的储存品质显著相关(P<0.05,下同),储存12个月后,增施氮肥导致稻米储存后食味品质变劣,N3处理下储存12个月后德优4727的食味值变化率达13.36%,显著高于N0、N1和N2处理;N3处理下旌优781的食味值变化率达18.19%,显著高于N0和N1处理。N3处理下德优4727和旌优781的直链淀粉含量变化率分别为14.02%和8.86%,均显著高于N2处理。稻米储存时间与直链淀粉含量、蛋白含量、糊化温度、消减值和回复值呈极显著正相关(P<0.01,下同),与食味值、峰值黏度、冷胶黏度、热浆黏度和崩解值呈极显著负相关。【结论】德优4727和旌优781在施氮量为150 kg/ha时产量增幅最大,食味品质最优。氮肥过度施入不仅影响稻谷食用品质,还加速稻米储存过程的老化。

【Objective】Clarify the relationship between nitrogen fertilizer level and storage time and rice taste quality,in order to provide theoretical basis for the actual production and storage of high-quality rice.【Method】High-yielding and high-quality rice,Deyou 4727(low-nitrogen high-efficiency type)and Jingyou 781(low-nitrogen low-efficiency type),were used as test materials.And set four nitrogen fertilizer levels as 0 kg/ha(N0),90 kg/ha(N1),150 kg/ha(N2),270 kg/ha(N3),the yield of rice produced under different nitrogen fertilizer levels and the changes of its protein,amylose content,starch viscosity and other taste qualities after storage for 3 months and 12 months were analyzed.The correlation between storage time and cooking flavour quality was also analyzed.【Result】Yield,protein content and straight-chain starch con-tent of Deyou 4727 and Jingyou 781 increased with increasing nitrogen application,the yield of N2 treatment increased the most,which were 31.63%and 28.86%respectively.The contents of protein and amylose in N3 treatment increased more than those in the other three treatments,and the taste value was the lowest.After 12 months of storage,the cooking and eating quality under N3 treatment was worse than other treatments.Nitrogen fertilizer level was significantly correlated with storage quality of rice(P<0.05,the same below).After 12 months of storage,the increased application of nitrogen fertilizer led to the deterioration of the taste quality of rice.The rate of change in taste value of Deyou 4727 after 12 months of storage under N3 treatment was 13.36%,which was significantly higher than that of N0,N1 and N2 treat-ments;the rate of change in taste value of Jingyou 781 under N3 treatment was 18.19%,which was significantly higher than that of N0 and N1 treatments.The change rates of amylose content of Deyou 4727 and Jingyou 781 were 14.02%and 8.86%respectively in N3 treatment,which were significantly higher than N2 treatment.Rice storage time showed extremely significant positive correlations with straight chain starch content,protein content,pasting temperature,abatement value and recovery value(P<0.01,the same below),and extremely significant negative correlations with flavour value,peak viscosity,cold gel viscosity,hot slurry viscosity and disintegration value.【Conclusion】Deyou 4727 and Jingyou 781 have the highest yield increase and the best taste quality when the nitrogen fertilizer level is 150 kg/ha.Over application of nitrogen fertilizer not only affects the edible quality of rice,but also accelerates the aging of rice during storage.