Essers A J, Ebong C, van der Grift R M, Nout M J, Otim-Nape W, Rosling H
Department of Food Science, Wageningen Agricultural University, The Netherlands.
Int J Food Sci Nutr. 1995 May;46(2):125-36. doi: 10.3109/09637489509012540.
Processing of cassava roots by the Alur tribe in Uganda includes a stage of solid substrate fermentation in heaps. Changes in cyanogen levels during the process, microflora involved, and protein levels, amino acid patterns and mycotoxin contamination of the final products were studied. Processing was monitored at six rural households and repeated at laboratory site, comparing it to sun-drying. Flour samples from rural households were analysed for residual cyanogens, mutagenicity, cytotoxicity and aflatoxins. Mean (+/- SD) total cyanogen levels in flours collected at rural households were 20.3 (+/- 16.8) mg CN equivalents kg-1 dry weight in 1990 (n = 23) and 65.7 (+/- 56.7) in 1992 (n = 21). Mean (+/- SD) levels of cyanohydrins plus HCN were 9.1 (+/- 8.7) in the 1992 flours. Total cyanogen levels in the village monitored batches were reduced considerably by heap-fermentation from 436.3 (+/- 140.7) to 20.4 (+/- 14.0) mg CN equivalents kg-1 dry weight cassava. Residual cyanogen levels were positively correlated with particle size of the resulting crumbs. Heap-fermentation was significantly more effective in reducing cyanogen levels than sun-drying alone, but did not always result in innocuous levels of of cyanogens. Dominant mycelial growth was from the fungi Neurospora sitophila, Geotrichum candidum and Rhizopus oryzae. No mutagenicity, cytotoxicity nor aflatoxins could be detected in the flours. Protein quantity and quality were not significantly reduced. Cassava gel viscosity pattern was modified to the consumers' preference by this method. As the removal of cyanogens was more efficient and we found no new obvious health risk, heap-fermentation can be regarded as an improvement compared to sun-drying alone in areas where cassava varieties with higher cyanogen levels prevail, but we recommend optimisation of the process for ensuring still safer products.
乌干达阿鲁尔部落对木薯根的加工包括在堆中进行固体基质发酵的阶段。研究了该过程中氰化物水平的变化、涉及的微生物群落，以及最终产品的蛋白质水平、氨基酸模式和霉菌毒素污染情况。在六个农村家庭对加工过程进行了监测，并在实验室场地重复进行，同时与晒干进行比较。对农村家庭的面粉样本进行了残留氰化物、致突变性、细胞毒性和黄曲霉毒素分析。1990年（n = 23）农村家庭收集的面粉中平均（±标准差）总氰化物水平为20.3（±16.8）毫克氰当量/千克干重，1992年（n = 21）为65.7（±56.7）。1992年面粉中氰醇加HCN的平均（±标准差）水平为9.1（±8.7）。通过堆发酵，村庄监测批次中木薯的总氰化物水平从436.3（±140.7）大幅降至20.4（±14.0）毫克氰当量/千克干重。残留氰化物水平与所得面包屑的颗粒大小呈正相关。堆发酵在降低氰化物水平方面比单独晒干显著更有效，但并不总能使氰化物水平达到无害程度。主要的菌丝生长来自嗜神经孢子菌、白地霉和米根霉。在面粉中未检测到致突变性、细胞毒性和黄曲霉毒素。蛋白质的数量和质量没有显著降低。通过这种方法，木薯凝胶粘度模式被调整为符合消费者的偏好。由于氰化物的去除更有效，且我们未发现新的明显健康风险，在氰化物水平较高的木薯品种占主导的地区，与单独晒干相比，堆发酵可被视为一种改进，但我们建议优化该过程以确保产品更安全。
