砻谷机工艺参数对丝苗米加工品质的影响规律

Effects of Process Parameters of Rice Huller on the Processing Qualities of Simiao Rice

砻谷工艺效果直接影响糙米的品质及成品米的质量。该研究以广东省5种丝苗米为原料,采用单因素试验,改变砻谷机线速差(1.20、1.61、2.03 m/s)和轧厚比——胶辊轧距与稻谷籽粒厚度之比(0.6、0.7、0.8),探究不同砻谷工艺参数下稻谷加工品质的变化规律。结果表明:经砻谷机一次脱壳,在线速差2.03 m/s、轧厚比0.6的参数组合下,5种稻谷的脱壳率为82.51%~86.21%,出糙率为57.82%~65.32%,糙碎率为8.43%~24.42%;在线速差1.20 m/s、轧厚比0.8的参数组合下,5种稻谷的脱壳率为78.82%~81.31%,出糙率为53.47%~62.06%,糙碎率为6.30%~21.36%。回砻谷后,5种稻谷的总脱壳率和总出糙率显著提高。美香粘的容重(527 g/L)较象竹香丝苗(428 g/L)大,粒长(8.53 mm)较象竹香丝苗(10.96 mm)小,在同一砻谷工艺参数下,美香粘的总出糙率较高(76.19%~78.63%),总糙碎率较低(6.84%~8.43%);象竹香丝苗的总出糙率较低(68.66%~71.30%),总糙碎率较高(8.56%~15.38%)。综合以上规律,总结出针对丝苗米依据稻谷品种的长度和容重调节砻谷机工艺参数的方法:对于容重较小的丝苗米品种,可适当设置较大的线速差和较小的轧厚比提高出糙率;对于长度较大,粒型较细长的丝苗米品种,可适当设置较小的线速差和较大的轧厚比以降低糙碎率。

The effect of rice hulling process has direct influence on the qualities of unpolished rice and finished rice.In this study,five kinds of Simiao rice from Guangdong province were used as raw materials.By changing line speed difference(1.20 m/s,1.61 m/s,2.03 m/s)and the gap-thickness ratio:the ratio of gap of rollers to grain thickness(0.6,0.7,0.8)of the rice huller,the change rules of processing qualities of rice were investigated under different process parameters of rice huller.After one-time husking by the rice huller,the husking ratio(HR),brown rice yield(BRY),percentage of generated broken rice(PGBR)of five kinds of paddies were 82.51%to 86.21%,57.82%to 65.32%and 8.43%to 24.42%respectively under the parameter combination of line speed difference of 2.03 m/s and gap-thickness ratio of 0.6.And under the parameter combination of line speed difference of 2.03 m/s and gap-thickness ratio of 0.6,HR,BRY and PGBR were 78.82%to 81.31%,53.47%~62.06%and 6.30%to 21.36%,respectively.With the re-husking of the rice huller,the total husking ratio(THR)and total brown rice yield(TBRY)of paddies increased significantly.The bulk density of‘Meixiangzhan’was 527 g/L,which was larger than that of‘Xiangzhuxiangsimiao’(428 g/L),and its grain length was 8.53 mm,which is smaller than that of‘Xiangzhuxiangsimiao’(10.96 mm).Under the process parameters,‘Meixiangzhan’had the higher TBRY(76.19%~78.63%)and the lower total percentage of generated broken rice(6.84%~8.43%);however,the TBRY of‘Xiangzhuxiangsimiao’was lower(68.66%~71.30%),and the total percentage of generated broken rice was higher(8.56%~15.38%).Based on the above change rules,the methods of adjusting the process parameters of rice huller according to the length and bulk density of rice varieties are summarized:for the Simiao rice with smaller bulk density,larger line speed difference and smaller gap-thickness ratio can be appropriately set to improve BRY;and for the Simiao rice with larger length and more slender grain shape,in order to reduce PGBR,small line speed difference and larger gapthickness ratio can be set appropriately.