Effect Of Dietary Added Thyme On Tan Sheep Mutton’s Flavor Substances

This study analyzed flavor quality of Tan sheep mutton among two Ningxia Tan sheep groups that respectively feeded on the total mixed diets added Thyme by5%and by10%, and the control group (without Thyme).This study carried out feeding trials, slaughter test and analyzed Tan mutton’s flavor related indicators after the slaughter and to explore the effect of Thyme on Tan Sheep mutton’s flavor substances.The study provided a scientific basis for the development of Thyme as green feed additive and vigorous promotion of the next feeding pattern of feeding would product better flavor of lamb.1. This study used completely random experimental design methods and carried out feeding trials and slaughter test.The study analyzed chemical indicators of slaughter performance and carcass quality to evaluate the impact of diets supplemented with thyme on Tan sheep fattening effects and carcass quality.The results showed that:(1) Diets added thyme improved Tan sheep’s weight gain and adding5%,10%thyme group respectively enhanced34.51%(P<0.05),10.21%(P>0.05) compared with the control group;Diets added thyme improved the slaughter rate and adding5%,10%thyme group respectively improved6.78%(P<0.01),2.11%(P>0.05) compared with the control group;Diets added thyme improved feed efficiency and adding5%,10%thyme group respectively improved34.06%,23.42%compared with the control group.(2) Diets added thyme improved the content of fat in the muscle and adding5%,10%thyme group respectively improved7.50%,27.97%compared with the control group;Diets added thyme improved the percentage of flavor amino acids in the total amino and adding5%,10%thyme group respectively improved1.22%,0.25%compared with the control group;The content of Cysteine can be improved and adding5%,10%thyme group respectively improved15.38%,23.08%compared with the control group;The content of the other amino acids were descending:the control group>5%thyme group>10%thyme group;Diets added thyme did not significantly (P>0.05)effect muscle’s the content of crude protein,moisture,crude ash,calcium and phosphorus.2.To explore the effect of thyme on Tan sheep mutton’s inosine acid which is the most important freshness substances of muscle and the rule of degradation,the test analyzed the quantity of Tan sheep mutton’s inosine acid and inosine, on the basis of HPLC.The result showed that diets added thyme can improve the content of inosine acid which related with the amount of added thyme,and adding5%,10%thyme group respectively improved11.76%(P<0.01),3.06%(P>0.05) compared with the control group;adding5%thyme group delayed the inosine’s degradation within eight days and inosine degradation generated inosine, adding5%thyme group can also enhance freshness value of muscle and extend the shelf life of the muscles.3.The study used37kinds of fatty acid methyl ester standards as an external standard and undecanoic acid triglyceride as the internal standard,and analyzed the qualitative and quantitative of fatty acids in Tan sheep’s muscles,on the basis of AOAC996.06that was acid hydrolysis extraction-gas chromatography.The results showed that:(1)Diets added thyme significantly improved the content of TFA and adding5%,10%thyme group respectively improved10.49%(P>0.05),35.25%(P<0.01) compared with the control group.(2) Diets added thyme improved the content of USFA and adding5%,10%thyme group respectively improved10.56%(P>0.05),39.62%(P<0.01) compared with the control group.(3)Diets added thyme significantly improved the content of PUFA and adding5%,10%thyme group respectively improved14.49%(P<0.01),14.97%(P<0.01) compared with the control group; Diets added thyme significantly improved the content of EPA(C20:5n3) and adding5%,10%thyme group respectively improved346.26%(P<0.01),178.23%(P<0.01) compared with the control group;Diets added thyme significantly increased the content of DHA(C22:6n3)and adding5%,10%thyme group respectively improved321.05%(P<0.01),171.05%(P<0.01) compared with the control group.In short,Diets added thyme can improve Tan sheep mutton’s USF, thereby thyme added into diets improved the nutritional value and flavor quality of Tan sheep mutton.4.The study analyzed the volatile flavor compounds of Tan sheep muscle,on the basis of HS-SPME and GC-MS technology. The results showed that:Diets added thyme improved the relative content of terpenoids, aromatic hydrocarbons, ketones and esters,and reduced the relative content of alkanes, alcohols and aldehyde in Tan sheep’s muscle.Adding5%,10%thyme group respectively improved49.17%,97.43%compared with the control group of terpenoids and respectively improved12.99%,33.80%compared with the control group of aromatic hydrocarbons.Diets added thyme the most obviously enhanced the terpenoids and aromatic compounds which are aromatic odor and the low threshold compounds,thus improved the Tan sheep mutton’s flavor.