Differences in breaking behavior of rice leaves under microwave and naturally drying processes

In order to fight for good farming time or harvest in bad weather,combine harvester will produce more broken leaves when threshing high moisture content rice,which will seriously hinder the grain cleaning effect.In this study,the breaking behavior of rice leaves under different microwave drying time and drying power was studied.Firstly,based on the appearance of freshly rice leaves undergoing microwave drying,the changing property of moisture content,weightlessness rate and temperature rise of rice leaves were tested and analyzed.Secondly,the tensile breaking force of freshly rice leaves under different microwave drying time and drying power was tested and compared with the tensile breaking force of naturally dried rice.Finally,the optimal microwaves parameters of rice leaves after drying which could result in greater breaking force than the natural drying state were obtained.The result showed that microwave drying method will reduce the moisture content of rice leaves and change the microstructure,which would affect the tensile-breaking property of rice leaves.The maximum tensile breaking force of rice leaves appeared at microwave dried power 70 W for 5-8 min and at microwave dried power 210 W for 3-4 min.The tensile breaking property of rice leaves at microwave dried power 350 W for 6-8 min were the weakest,which was lower than that of fresh rice leaves.Therefore,the optimal microwave drying parameters of rice leaves will provide a basis for the application of microwave technology in the threshing process.

冻干方便米饭品质评价方法及原料适应性的研究

本试验选取了10个品种的大米制作冻干方便米饭,测定了大米的直链淀粉含量和蛋白质含量,并且分析了这两项指标与感官指标以及物性指标(Texture Profile Analysis,TPA)与感官指标的相关关系。研究发现感官指标中的口感与大米的直链淀粉含量呈极显著的负相关,与TPA实验的Hardness和Adhesiveness两项指标呈极显著的负相关。结果表明大米的直链淀粉含量对冻干方便米饭品质有着显著的影响,利用TPA实验可以替代感观评价对冻干方便米饭的品质进行评价,其中利用直链淀粉含量相对较低的粳米制作的冻干方便米饭的口感较好。

不同状态下海参中的铝含量测定及安全分析

目的建立微波消解-电感耦合等离子体质谱测定海参中铝含量的方法,并比较评价不同状态下海参中的铝含量。方法选取不同地市的30个干海参样品和15个即食海参样品,经微波消解后,采用电感耦合等离子体质谱进行测定。结果铝在0~2.0mg/L质量浓度内的线性关系良好,相关系数为0.9998,该方法检出限为0.5 mg/kg,加标回收率为96%~102%,相对标准偏差为1.18%~1.77%。测定的30个干海参直接粉碎后的样本中铝含量在100 mg/kg以上的占73.3%,测定干海参复水后的样本中铝含量均在100 mg/kg以下, 15个即食海参样本中铝含量也均在100mg/kg以下。结论本方法准确度高、精密度好,适用于不同状态下海参中铝含量的测定。从海参不同样品处理铝含量检测结果来看,干海参泡水后达到可食用状态时,铝的含量会远远低于干海参泡水前的铝含量,随机选取的即食海参中铝的含量均很低,检测消费者食用状态下海参的铝含量情况,更能对干海参的食用安全进行科学、合理的评价。

响应面法优化冻干方便米饭中复合添加剂的配方

利用响应面分析法(RSM)对冻干米饭复合添加剂的配方进行优化。在单因素试验基础上选取试验因素与水平,根据中心组合(Box-Behnken)试验设计原理采用三因素三水平的响应面分析法对各个因素的显著性和交互作用进行分析,结果表明:优化出的最佳配方为:β-环状糊精0.98%、海藻糖2.11%、β-淀粉酶1.12%,在此条件下方便米饭的糊化度达96.20%,感官评分为9.2,冻干方便米饭品质优良。