摘要
在糙米碾米过程中普遍存在碎米较多及碾米能耗高的问题,为改善糙米碾米品质,提出以纤维素酶和木聚糖酶的复合酶溶液处理替代常规水加湿方法的酶法预处理工艺。以贮藏期糙米(含水率15%以下)为原料,采用二次正交旋转中心组合设计试验,研究复合酶溶液处理工艺中复合酶配比、酶质量浓度、加液量及酶处理时间对碾米后整精米率和碾米能耗的影响规律,建立了各因素对整精米率和碾米能耗影响的数学模型。结果表明:构建的整精米率、碾米能耗与复合酶配比、酶质量浓度、加液量及酶处理时间之间的回归方程极显著(P<0.01),得到优化参数组合为纤维素酶和木聚糖酶质量比1.3∶1 g/g、复合酶溶液质量浓度65 mg/m L、加液量1.25%,酶处理时间102 min,该条件下整精米率为80.07%、碾米能耗为90.72 k J/kg。复合酶溶液处理后整精米率较加湿调质处理提高约3.98%,节约能耗约13.06%;较纤维素单一酶溶液加湿处理后整精米率提高约0.98%,节约能耗约5.48%。并通过微观结构分析证实了糙米皮层粗纤维的局部破损是其碾米性能改善的主要原因。研究结果可为实际生产条件下的酶法糙米预处理工艺提供参考。
Generally, lots of broken rice is generated and high energy consumption occurs during the rice milling processing, which bring adverse effect to the economic benefits of rice milling enterprises. Therefore, milling quality improvement is of important significance in practice for rice processing indus,3,. Moisture conditioning treatment for the brown rice, which is an advanced technology, can increase head rice yield and reduce the milling energy consumption to some extent. It reduces the maximum compressive strength and maximum tensile strength with the increase of moisture content and generated moisture gradient within the rice by gradual penetration from the exterior into the interior of kernels. However, it does not fundamentally solve the problem caused by the resistant cortex of brown rice. The brown rice＇s tough cortex is mainly caused by the coarse fiber structure, whose major components are cellulose and araboxylan. This study proposes a new process with composite enzyme of cellulase and xylanase instead of the conventional humidifying method. This method substantially decreases broken rice in the milling process and reduces the milling energy consumption to improve milling quality. The humidification of compound enzyme solution selectively degrades the cortex of brown flee, which can not only reduce the hardness of brown rice kernel and decrease the whitening pressure, but also facilitate the moisture penetration, which would boost cortex softening and increase the grain＇s toughness. Moreover, the synergy of compound enzyme can improve the efficiency of the enzymatic hydrolysis. A central composite rotatable orthogonal experimental design of response surface methodology with 4 factors and 5 levels was employed. Taking brown rice in storage with moisture content below 15% as raw material, the influences of the 4 parameters including ceUulose-to-xylanase mass ratio, concentration of compound enzyme solution, adding liquid proportion and enzyme treating time on the head rice yield and the milling energy
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2015年第16期264-271,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
黑龙江省教育厅项目(1254CGZH18)
哈尔滨市应用技术研究与开发项目(2013DB2BG005)
关键词
酶
模型
品质控制
复合酶法预处理
糙米
碾米性能
皮层特征
enzymes
models
quality control
compound enzyme solution humidification
brown rice
milling quality
cortex characteristic
