响应面法优化鸡肝发酵工艺

Optimization of Fermentation Process for Chicken Liver by Response Surface Methodology

采用益生菌对鸡肝进行发酵。从3种菌株(植物乳杆菌LP1、发酵乳杆菌LF1、枯草芽孢杆菌BS1)中选择生长能力和产酸能力最强的植物乳杆菌LP1作为发酵剂,以发酵初始pH值、葡萄糖添加量、接种量、发酵时间和料液比5个因素进行单因素试验。在此基础上,以发酵鸡肝A_(280 nm)为指标,采用响应面分析法进行3因素3水平响应面优化试验,结果表明:各因素对发酵鸡肝A_(280 nm)的影响大小为发酵初始pH值>料液比>接种量,经过优化得到的最佳发酵工艺为:发酵初始pH 5.57、料液比1∶3.55(m/V)、接种量1.5%,最终发酵鸡肝A_(280 nm)为1.537;发酵鸡肝游离氨基酸和必需氨基酸总含量均显著增加(P<0.05),说明发酵能促使蛋白质分解,进一步提升鸡肝的营养价值。

In this study,three different probiotics(Lactobacillus plantarum LP1,Lactobacillus fermentum LF1,and Bacillus subtilis BS1)were used to ferment chicken liver.Among these,Lactobacillus plantarum LP1 was found to have the strongest growth and acid production capacity and thus was selected as the starter for further fermentation.Single-factor experiments were carried out with five variables,initial fermentation pH,glucose addition,inoculum size,fermentation time and solid-toliquid ratio.On this basis,the fermentation process was optimized by response surface methodology using three variables at three levels each.The results showed that the influence of three variables on the absorbance at 280 nm(A_(280 nm))of fermented chicken liver was in decreasing order as follows:initial pH of fermentation medium>solid-to-liquid ratio>inoculum size.The optimal fermentation conditions were determined as initial pH of fermentation medium,solid-to-liquid ratio for 5.57,1:3.55(m/V)and 1.5%,respectively.The A_(280 nm)of fermented chicken liver obtained under the optimized conditions was 1.537.The total contents of free amino acids and essential amino acids in chicken liver increased significantly after optimization(P<0.05),indicating that fermentation can promote the decomposition of chicken liver protein and thereby improve the nutritional value of chicken liver.