不同处理方式复合菌固体发酵野生构树叶制备蛋白饲料的工艺优化

Optimization of Preparation Process of Protein Feed by Solid Fermentation of Wild Broussonetia papyrifera Leaves with Different Treatment Methods

为降低构树叶中单宁含量,采用蒸汽爆破、球磨等方式对构树叶进行预处理,以抗营养因子单宁含量为考察指标,通过响应面分析法确定枯草芽孢杆菌、乳酸菌和酿酒酵母菌的复合菌固态发酵构树叶制备蛋白饲料的最佳工艺。结果表明:最佳工艺条件为汽爆压强1.4 MPa,维压时间90 s;球磨时间20 min;发酵时间4 d,含水量60%,发酵温度32.50℃,酿酒酵母菌:乳酸菌:枯草芽孢杆菌=1:1:1。构树叶经发酵、汽爆后发酵和球磨发酵后发酵单宁含量分别降低了36.2%、39.5%和60.5%;粗蛋白含量分别增加了23.59%、10.28%和7.84%;粗灰分含量分别增加了16.7%、31.80%和24.23%;粗纤维含量分别降低了15.33%、12.32%和7.85%。构树叶的钙含量为2.70%,经发酵后钙含量无明显变化,经汽爆发酵后和球磨发酵后分别增加了23.33%和22.22%(P<0.05),预处理和发酵对磷和粗脂肪的含量几乎无影响,磷含量约为0.3%,粗脂肪含量约为2.4%。原料发酵、汽爆发酵和球磨发酵的酶活力分别高达41.43、44.77和65.10 U。球磨发酵降单宁效果要远远优于汽爆发酵和原料发酵,原料发酵的蛋白增加效果最佳。

To reduce tannin content in Broussonetia papyrifera leaves,steam explosion and ball milling were used to pretreat Broussonetia papyrifera leaves,and response surface methodology was used to determine the best technology for preparing protein feed by solid fermentation of Broussonetia papyrifera leaves with complex bacteria of Bacillus subtilis,lactic acid bacteria and Saccharomyces cerevisiae.Results showed that,the optimum process conditions were as follows:Steam explosion pressure 1.4 MPa,maintaining pressure time 90 s.The ball milling time was 20 min.The fermentation time was 4 d,water content was 60.07%,fermentation temperature was 32.50℃,and the ratio of Saccharomyces cerevisiae:lactic acid bacteria:Bacillus subtilis was 1:1:1.The tannin content of Broussonetia papyrifera leaves after fermentation,steam explosion fermentation and ball milling decreased by 36.2%,39.5%and 60.5%respectively.The crude protein content increased by 23.59%,10.28%and 7.84%respectively.Crude ash content increased by 16.7%,31.80%and 24.23%respectively.The crude fiber content decreased by 15.33%,12.32%and 7.85%respectively.The calcium content of Broussonetia papyrifera leaves was 2.70%,which had no obvious change after fermentation.But the calcium content increased by 23.33%and 22.22%respectively after steam explosion and ball milling(P<0.05)by fermentation.Pretreatment and fermentation had little effect on phosphorus and crude fat content,with phosphorus content being 0.3%and crude fat content being 2.4%.The enzyme activities of raw material fermentation,steam explosion fermentation and ball milling fermentation were as high as 41.43,44.77 and 65.10 U.The tannin reduction effect of ball milling fermentation is far superior to steam explosion fermentation and raw material fermentation,and the protein increase effect of raw material fermentation is the best.