Research On Cadmium Detection Technology And Fermentation To Subtractive Cadmium In Rice Noodle

Fermented rice noodle is a kind of rice production with rice as raw material made by fermentation, washing, grinding, galvanization, retro-gradation and cooling. Fermented rice noodle is a popular traditional food with rich nutrition, easy to digest and convenient. In recent years, became more and more serious which caused by the environmental pollution. The main raw material of fermented rice noodle is rice. The problem of "excessive cadmium" rice will lead to some unstable factors of fermented rice noodle and food security. Development of rice cadmium reduction technology research is of great significance to reduce the cadmium content in the fermented rice noodle. It can improve the quality and safety of fermented rice noodle, ensure the health of consumers and promote the healthy development of fermented rice noodle industry.On the basis of the methods of fermented rice noodle cadmium determination. This paper focused on the fermented rice noodle vermicelli production, and use the technology of strain which contain Lactobacillus plantarum, Saccharomyces cerevisiae and Bacillus acidophilus to reduce cadmium in fermented rice noodle. This paper determined the mixed cadmium reduction liquid ratio in fermented rice noodle and the best fermentation conditions of fermented rice noodle. Finally, the decreased rate of cadmium in fermented rice noodle was more than 86%.The main conclusions of the study were as follows:1、Optimize for condition before detected cadmium in fermented rice noodleIt is necessary to sample pretreatment when using atomic absorption spectroscopy for determination of cadmium. The pretreatment process was not only the longest process but also the key to the atomic absorption spectroscopy detection. This process often determines the accuracy of the test result. This part focused on the influence of digestion solution, digestion time, digestion temperature on cadmium recovery rate. The optimal conditions of wet digestion were:the best digestion solution was 7ml+3ml+lml hydrogen peroxide, nitricacid chlorine acid, the best digestion temperature gradient was:90℃～150℃～150℃, the best digestion time gradient was: 30min-60min-120min, using step wise digestion method. It used above optimized conditions to do the experiment and determination of the cadmium recovery rate, It can find that the difference of cadmium recovery rate of wet digestion and microwave digestion was less than 10%.2、Optimize for mixed cadmium reduction liquid ratio in fermented rice noodleOn the basis of traditional production process in fermented rice noodle. This part had an inoculation to fermented rice noodle in fermentation process that for investigated the effect of the plant Lactobacillus, yeast, Lactobacillus acidulous suspension on cadmium decreased rate in fermented rice noodle. This part used the central composite design and response surface analysis to Establish the regression models:Y=78.38+4.38A-1.97B+1.42C+1.72AB-0.52AC+4.68BC-3.57 A2-3.18B2-1.09C2, in the models, Y stands for cadmium reduction percentage, A stands for adding amount of Lactobacillus plant-arum suspension, B stands for adding amount of yeast suspension, C stands for adding amount of Lactobacillus acidulous. It confirmed the proportion of three strains:Lactobacillus suspension was 35%, yeast suspension was 30%, Lactobacillus acidulous suspension was 35%. When experiment under above proportion, the cadmium reduction percentage was 79.94%.3、 Optimize for cadmium reduction fermentation process in fermented rice noodleThis part using rice as raw material that the cadmium content was 0.2084 mg/kg,0.4054 mg/kg,0.5061 mg/kg. On the basis of a fixed suspension of plant Lactobacillus, yeast, Lactobacillus acidulous. This chapter investigated the effects of the cadmium reduction percentage in fermented rice noodle on added amount of three strains suspension, fermentation temperature, fermentation time and washing times. The design of experiment was orthogonal that was three the three level, the variance analysis tool was SPSS 17.0. Finally, the optimum conditions of cadmium reduction were determined:(1) The optimal fermentation conditions of 0.2084mg/kg cadmium content rice raw material is:fermentation temperature 39℃, fermentation time 20h, added amount of three strains suspension 6%, on the conditions of above parameters the cadmium reduction rate was 89.4%; (2)The optimal fermentation conditions of 0.4054mg/kg,0.5061 mg/kg cadmium content rice raw material was: fermentation temperature 37℃, fermentation time 32h, added amount of three strains suspension 8%, on the conditions of above parameters the cadmium reduction rate was 86.6%,87.2%, respectively.