粒型和含水率对籼糙米力学特性的影响

Effects of Grain Shape and Moisture Content on Mechanical Properties of Indica Brown Rice

大米加工过程中会产生破碎籽粒,降低整精米率和影响大米食用品质。研究3种籼糙米的力学特性影响因素(含水率、糙米粒型)与籼糙米碾白品质之间的关系,结果表明,籼糙米含水量增加会逐渐降低压缩力、剪切力、三点弯曲力的破碎力值,含水率从12.88%增加到16.46%时,压缩破碎力值、剪切破碎力值和三点弯曲破碎力值分别降低了22.17、6.92 N和2.38 N。沙软粘、美香粘和天龙一号的厚度平均值为1.59、1.67 mm和1.65 mm,三点弯曲破碎力平均值分别为17.20、18.28 N和20.18 N。沙软粘糙米有31%的籽粒厚度为1.60 mm,美香粘糙米有30%的籽粒厚度为1.70 mm,天龙一号种糙米有46%的籽粒厚度为1.65 mm。达到加工精度即碾减率为10%时,沙软粘、美香粘和天龙一号的碎米率分别为18.50%、16.30%和16.60%。因此厚度均匀性高的糙米碾白产生的碎米少。

The loss of grain caused by broken grains during rice processing reduces the rate of head rice and affects the edible quality of rice.In the present paper,the effects of moisture content,brown rice grain type on the mechanical properties of three cultivars of indica brown rice and the milling quality of brown rice were researched.The force needed to increase water content of indica brown rice caused the decrease of the force of to break.When the water content increased from 12.88%to 16.46%,the compressive force,shearing force and three-point bending force to break the grain decreased by 22.17,6.92 N and 2.38 N,respectively.The average thickness of Sha Ruanzhan,Meixiangzhan and Tianlong No.1 was 1.59,1.67 mm and 1.65 mm,and the average three-point bending force to break the grain was 17.20,18.28 N and 20.18 N,respectively.The thickness of 31%of Sharuanzhan brown rice grains 1.60 mm,that of 30%of Meixiangzhan brown rice grain was 1.70 mm,and that of 46%of Tianlong No.1 brown rice grains was 1.65 mm,respectively.When the degree of milling was same to 10%,the broken rice rate of Sharuanzhan,Meixiangzhan and Tianlong No.1 was 18.50%,16.30%and 16.60%,respectively.Therefore,brown rice with higher uniformity of thickness led less broken rice.