香蕉茎叶粉固态发酵条件优化及鹅对其养分利用率的研究

摘要

本试验旨在研究应用固态发酵技术改善香蕉茎叶粉养分组成的工艺参数及鹅对其养分的利用率.选择米曲霉和产朊假丝酵母作为发酵菌种,逐步探究5个因素(单菌种发酵、硫酸铵添加量、米曲霉和产朊假丝酵母接种比例、混合菌液接种量)对发酵后香蕉茎叶粉蛋白质含量的影响.利用正交设计筛选最优发酵温度、底物水分和发酵时间的组合.结果显示:米曲霉和产朊假丝酵母单独发酵均能显著或极显著提高发酵后香蕉茎叶粉的粗蛋白质含量(P<0.05或P<0.01).添加硫酸铵能显著或极显著提高发酵后香蕉茎叶粉的真蛋白质含量(P<0.05或P<0.01),其中添加2%硫酸铵组的真蛋白质含量最高.米曲霉:产朊假丝酵母接种比例为2:1的处理发酵后香蕉茎叶粉的蛋白质净增加量显著或极显著高于比例为1:1、1:3和3:2的处理(P<0.05或P<0.01).正交试验结果显示,以4%的接种量、接种比例为2:1(米曲霉:产朊假丝酵母)、2%的硫酸铵添加量,在基质水分为50%,30℃的环境下发酵4 d效果最佳.经过该工艺发酵后的香蕉茎叶粉粗蛋白质含量提高了33.82%,氨基酸分析结果显示,除赖氨酸和精氨酸外其余的15种氨基酸含量均有不同程度的提高.马冈鹅的代谢试验结果显示,发酵后香蕉茎叶粉中的粗蛋白质利用率提高了52.66%,极显著高于发酵前(P<0.01);此外,代谢能和能量利用率也都略有提高(P>0.05).由此可见,经过该发酵工艺发酵后的香蕉茎叶粉营养价值不仅得到了改善,也促进了鹅对其养分的消化吸收.%This study was conducted to use the solid state fermentation technology to improve nutrient composi-tion of banana stems and leaves and its nutrient utilization for geese. Choosing Aspergillus oryzae and Candida utilis as fermentation strains to investigate the influences of 5 factors [ single strain fermentation, addition of (NH4)2SO4, proportion of Aspergillus oryzae and Candida utilis, mixed bacteria liquid inoculation] on the protein content of banana stems and leaves powder after fermentation. Using orthogonal design to find out the optimal combination of fermentation temperature, fermentation time and substrate moisture. The results showed that using Aspergillus oryzae or Candida utilis as single fermentation strain could significantly increase the crude protein content of fermented banana stems and leaves powder ( P<0. 05 or P<0. 01 ) . Fermentation with (NH4)2SO4 addition could significantly increase true protein content of fermented banana stems and leaves powder ( P<0.05 or P<0.01) , especially 2% addition. The net increase in protein treated with the proportion of Aspergillus oryzae and Candida utilis by 2:1 significantly higher than that of the proportion of 1:1, 1:3 and 3:2 ( P<0.05 or P<0.01) . The results of orthogonal test showed that the best fermentation condition were 4%inoculation (the proportion of Aspergillus oryzae and Candida utilis by 2:1) and 2% (NH4)2SO4 addition, and fermenting in 50% substrate moisture, 30 ℃ for 4 days. The crude protein content of banana stems and leaves increased by 33.82% after this fermentation process. The amino acid analysis showed that there were 15 kinds of amino acids increased differently beside lysine and arginine. The metabolic test results of Magang geese showed that the crude protein utilization of banana stems and leaves powder after fermentation significant-ly increased by 52.66% comparing with the banana stems and leaves powder without fermentation ( P<0.01) , additionally, the energy and metabolic energy utilization were increased slightly as well. In conclusion, the nu-tritional value of banana stems and leaves powder is improved after this fermentation process, and also promote the digestion and absorption of nutrient of geese.