微生物法削减大米粉中镉的工艺研究及品质分析

The study of the removal of cadmium in the rice by microorganisms and effects on the qualities of rice flour

笔者在本研究中提出了用正交法优化微生物发酵法削减大米粉中镉污染的工艺条件,在最优条件下测定了微生物发酵对两种污染程度不同的大米的主要化学成分的影响,并用差示扫描量热法(differential scanning calorimetry,DSC)、X射线衍射(X ray diffraction,XRD)、红外光谱等方法分别研究了微生物发酵大米热力学特征、淀粉晶体结构及官能团的影响。结果表明,最佳的发酵菌种为植物乳杆菌,发酵法削减大米中镉的最佳条件为接种量3.5%,发酵时间为48h,料液比为1:3。在此条件下,镉含量为0.459±0.006mg/kg米中的镉去除率达到80.02±1.10%,可以得到镉含量为0.092±0.003 mg/kg的大米;镉含量为0.873±0.031mg/kg大米的镉去除率达到77.25±4.47%,可以得到镉含量为0.199±0.039mg/kg的大米。在最佳工艺条件下,两种大米中的水分和蛋白质、淀粉含量显著降低(p<0.05),脂肪含量也有略微下降。两种大米发酵后糊化起始温度降低,污染较小的大米峰值温度降低,而污染较严重的大米峰值温度变化不大。两种大米的结晶度都有一定下降,特别是污染程度较低的大米下降明显。但两种大米在发酵过程中都没有发生剧烈的化学变化而产生新的化学键或基团。

In this paper,we optimized the condition for removing cadmium in rice with microbiology by the orthogonal method.We determined the effect of the optimized treatment for cadmium removal on main components retention of two kinds of rice with different levels of pollution（0.459±0.006 kg/mg,0.873±0.031 mg/kg）.And by using differential scanning calorimetry（DSC）,X ray diffraction（XRD）and infrared spectrometry respectively,we studied the effects of thermodynamic characteristics and starch crystal structure and functional group of the fermentation rice.The results showed that the best fermented strainswas lactobacillus plantarum,and the best condition to remove cadmium in rice was inoculation amount of3.5%,water to liquid ratio of 1：3,during time 48 h,and the removal rate of cadmium in rice（cadmium content of 0.459±0.006 mg/kg）was 80.02±1.10%,which could obtain rice with a cadmium content of0.092±0.003 kg/mg;As for another rice（cadmium content of 0.873±0.031 mg/kg）,the removal rate of cadmium was 77.25±4.47%,which could obtain cadmium content of 0.199±0.039 mg/kg.Under the best technological conditions,the moisture,starch and protein content in the rice decreased significantly（p0.05）,and the contents of fat also decreased.After gelatinization,the initial temperature of gelatinization of two kinds of rice decreased,the peak temperature decreased in the mildly polluted rice and changed little in the more serious polluted rice.The starch crystallinity of the fermentation rice decreased,especially the more serious polluted rice decreased significantly.There were no new chemical bonds or group produced in the process of fermentation in two kinds of rice which indicated that fermentation did not lead severe chemical changes.