储藏条件及加工精度对早籼稻脂肪酸值的影响研究

EFFECTS OF STORAGE CONDITIONS AND PROCESSING ACCURACY ON FATTY ACID VALUES OF EARLY INDICA RICE

为研究储藏条件及加工精度对早籼稻脂肪酸值的影响,取6种早籼稻在15℃、25℃、35℃,相对湿度60%~65%条件下模拟储存18个月,测定其脂肪酸值;将不同脂肪酸值梯度的早籼稻进行适碾和精碾后,研究其脂肪酸值的变化。结果表明,随着储藏时间的延长,稻谷脂肪酸值逐渐增加,储存温度越高,其脂肪酸值增加越快。15℃、25℃条件下,储存18个月脂肪酸值均小于等于25(KOH/干基)/(mg/100g)。在35℃条件下,储存18个月,大部分稻谷的脂肪酸值达到轻度不宜存或重度不宜存。不同品种稻谷脂肪酸值在15℃、25℃条件下储存,品种之间差异不大,35℃条件下储存,品种间差异较大。早籼稻经适碾和精碾后,大米的脂肪酸值显著降低,其中精碾降幅更大,最高可达29.8(KOH/干基)/(mg/100g)。稻谷经适碾或精碾加工,脂肪酸值可降低约30%~70%。适碾大米和精碾大米的脂肪酸值均与稻谷脂肪酸值呈正相关关系,相关系数分别为0.90和0.72。综上,将早籼稻储藏温度控制在25℃以内,适度加工,可保障稻谷储存和加工品质,安全经济、节能降损。

In order to study the effect of storage conditions and processing accuracy on fatty acid value of early indica rice, six kinds of early indica rice were stored at 15℃, 25℃, 35℃ and the relative humidity 60%~65% for 18 months, and the fatty acid value was determined. The early indica rice with different gradient of fatty acid values was studied after suitable and fine milling. The results showed that the fatty acid value of rice increased gradually with the extension of storage time, and the fatty acid value increased faster with the increase of storage temperature. At 15℃ and 25℃, the fatty acid value of the rice stored 18 months was less than or equal to 25(KOH/dry basis)/(mg/100 g). At 35℃ for storing 18 months, the fatty acid value of most rice reached mild or severe unfavorable storage. The fatty acid values of different rice varieties were not significantly different when stored at 15℃ and 25℃, while the fatty acid values of different rice varieties were significantly different when stored at 35℃. The fatty acid value of early indica rice decreased significantly after suitable and fine milling, and the decrease of fine milling was greater, up to 29.8(KOH/dry basis)/(mg/100 g). The fatty acid value of rice can be reduced by 30% to 70% after milling or finishing milling. There was a positive correlation between the fatty acid values of suitable rice or fine rice, and the correlation coefficients were 0.90 and 0.72, respectively. In conclusion, the storage temperature of early indica rice is controlled within 25℃, and moderate processing can ensure the storage and processing quality of rice, which is safe and economical, energy saving and loss reduction.