镉超标大米水解糖发酵生产2-酮基葡萄糖酸过程中镉的迁移规律

目的 揭示以镉超标大米为原料发酵生产2-酮基葡萄糖酸过程中镉的迁移规律，并获得符合食品抗氧化剂D-异抗坏血酸钠合成要求的2-酮基葡萄糖酸。方法 以正常大米、镉超标大米和混合大米为原料，系统分析大米糖化、种子培养、2-酮基葡萄糖酸发酵、发酵产物提取等过程中镉的含量和分布，确定镉的迁移规律及其对2-酮基葡萄糖酸发酵性能和D-异抗坏血酸钠产品品质的影响。结果 大米原料和辅料碳酸钙中的镉的含量对2-酮基葡萄糖酸发酵性能影响不显著；发酵产物的提取过程有效降低了2-酮基葡萄糖酸中的镉含量，提取过程中产生的酸化废渣（主要由硫酸钙和菌体组成）可富集90%以上的镉；以镉超标大米为原料制备的D-异抗坏血酸钠的质量符合国家标准要求，未检出镉的存在。结论 该研究为综合利用镉超标大米生产2-酮基葡萄糖酸、进而生产高附加值的食品添加剂D-异抗坏血酸钠提供了理论依据和技术支撑。

Migration law of cadmium during 2-ketogluconic acid production using hydrolysate of cadmium-contaminated rice as raw material

Objective To reveal the migration law of cadmium during 2-ketogluconic acid production using hydrolysate of cadmium-contaminated rice as raw material, and produce 2-ketogluconic acid meeting the requirement for synthesis of food antioxidant sodium erythorbate. Methods Contents and distributions of cadmium during processes of saccharification, seed culture and fermentation of 2-ketogluconic acid, and 2-ketogluconic acid extraction and purification were systematically analyzed using normal rice, cadmium-contaminated rice and mixed rice as raw materials to confirm the migration law of cadmium and its effect on the fermentation performance of 2-ketogluconic acid and the quality of sodium erythorbate. Results Cadmium in the rice and calcium carbonate has no significant effect on the fermentation performance of 2KGA. The extraction and purification process of 2-ketogluconic acid could effectively reduce the cadmium content in 2-ketogluconic acid. Over 90% of cadmium has been accumulated in the acidification waste residue (mainly composed of calcium sulfate and bacterial cells). The quality of sodium erythorbate produced by using cadmium-contaminated rice as raw material meets the requirements of National Standards, with no detection of cadmium. Conclusion The present study provides a theoretical basis and technical support for the comprehensive utilization of cadmium-contaminated rice to produce 2-ketogluconic acid for synthesizing high value-added food additive sodium erythorbate.