Quality Improvement of Cassava Residue by Solid-State Fermentation with Aspergillus niger

In this study,a solid-state fermentation( SSF) using Aspergillus niger was conducted to improve the nutritional quality of cassava residue and the optimal fermentation parameters w ere investigated. Firstly,a single factor experiment design w as adopted to screen the optimal fungi inoculation size,rapeseed meal supplemental level,fermentation time,fermentation temperature,the ratio of substrate to moisture and initial pH according to the nutritional value of fermented cassava residue. An orthogonal experiment design w as further used to investigate the effects of fermentation parameters such as fermentation time,fermentation temperature,the ratio of substrate to moisture and initial pH on the nutritional quality of cassava residue. The results show ed as follow s: 1) inoculated 3 × 106 Aspergillus niger spore per gram fermentation materials,added 15% rapeseed meal,controlled the ratio of substrate to w ater 1: 1.50 and fermented w ith initial pH 4 at 36 ℃ for 4 days could get the optimal result. 2) Fermented cassava residue under the optimized condition described above and calculated based on dry matter,the crude fiber content w as decreased from 22.26% to 17.71%( P0.05) and the reducing sugar content w as increased from 1.42% to 5.11%( P 0.05),crude protein content w as increased from 8.67% to 13.48%( P0.05),crude fat content w as increased from 7.89% to 11.72%( P0.05),the ash content w as increased from 6.02% to 7.31%( P0.05) after SSF,Moreover,after fermentation the enzyme activities of carboxy methyl cellulase,filter paper activity and β-glucosidase reached 9. 05,2. 37,2.35 U /g,respectively. Our results suggest that the SSF w ith Aspergillus niger offers an effective alternative to improving the nutritional value of cassava residue.