饲喂干酪乳杆菌K17对加州鲈鱼肌肉滋味的影响

Impact of Supplement of Lactobacillus casei K17 on Fillet Tastes of Largemouth Bass Micropterus salmoides

为改善饲喂加州鲈鱼肌肉的滋味,研究了添加干酪乳杆菌K17的饲料对加州鲈鱼肌肉滋味物质的影响。试验分为6组:含1×10^(8)CFU/g干酪乳杆菌K17的饲料组(LB),含10%脱脂乳粉保护的1×10^(8)CFU/g干酪乳杆菌K17的饲料组(MB),含1×10^(8)CFU/g热灭活干酪乳杆菌K17的饲料组(DB),含发酵上清液的饲料组(FS)、含10%脱脂乳粉的饲料组(MG)及含0.85%生理盐水的饲料组(SG)。实验结束后,利用电子舌测定了不同处理组样本的整体滋味差异,并分析了其呈味氨基酸和呈味核苷酸的含量。结果显示,通过电子舌主成分分析和判别因子分析,可将6组的差异性进行有效区分;采用雷达图能将各组鲜味、苦味和甜味大小区分。6组加州鲈鱼肌肉中检测出16种游离氨基酸。MB组鲜味氨基酸总量和天冬氨酸含量,FS组缬氨酸、异亮氨酸、亮氨酸、苯丙氨酸含量和苦味氨基酸总量和MG组的必需氨基酸总量显著高于对照组SG(P<0.05)。MB组的味精当量(Equivalent umami concentrations,EUC)增加最明显,与对照组相比差异显著(P<0.05),6组EUC的大小为MB>FS>DB>LB>MG>SG,与电子舌预测结果基本一致。以上研究表明,饲喂不同剂型干酪乳杆菌K17对加州鲈鱼滋味成分和含量的影响存在一定差异,MB组对加州鲈鱼肌肉整体滋味贡献最大,这可为其在加州鲈鱼中应用提供理论依据。

Impact of supplement of Lactobacillus casei K17 on fillet tastes of largemouth bass Micropterus salmoides were researched for improving its fillet tastes. The M. salmoides was given commercial feed supplemented with live L. casei K17(1×10^(8) CFU/g), live L. casei K17 protected by skim milk powder(10%), heat-killed dead L. casei K17, its fermentation supernatant, skim milk powder(10%), and saline(0.85% NaCl), designated as LB, MB, DB, FS, MG, and SG, respectively.At the end of the trial, the outline of the whole taste difference of each group was determined by using the electronic tongue.The contents of free amino acids and flavor nucleotides were analyzed. The results showed that the electronic tongue adopted discriminant factor analysis based on principal component analysis, the difference of six groups could be effectively distinguished, and the umami, bitter and sweet taste of each group could be effectively distinguished by using radar map. Sixteen free amino acids were detected from the fillet of six groups. Total umami amino acids and aspartic acid(Asp) in the MB group, the valine(Val), isoleucine(Ile), leucine(Leu), phenylalanine(Phe) and total bitter amino acids in the FS group, and the total essential amino acids in the MG group were significantly higher than those in the control SG group(P<0.05). Combined with equivalent umami concentrations(EUC), MB group had the most significant increase in EUC compared with the control group, and the order was MB>FS>DB>LB>MG>SG. Consistent with the predicted results of the electronic tongue, EUC was recommended to quantify the umami of fish fillet. These results showed the fillet taste compositions and contents of M. salmoides fed with different L. casei K17 diets were improved obviously compared with the control group, especially LB and MB, which could provide a useful theoretical reference for further development and utilization of M. salmoides.