Studies On The Rule Of Quality Forming And Technology Improvement Of Airing Yak Beef

By multivariate analysis method, the descriptive words used for sensory profile of the airing yakbeef were obtained. By detecting the quality and microorganism indicator of airing yak beef samples indifferent stages to study the rule of quality forming and changes of microorganism, the amino acid andfatty acid composition assay were analyzed and evaluated by comparing yak meat with airing yak meat.Then improve the flavor of the airing yak meat by Box-Behnken method.The results were as below:1. By multivariate analysis method, flavor and texture were obtained as the descriptive words usedfor sensory profile of the airing yak beef. Then by drawing the sensory profile of six products boughtfrom the market, the nutrition and quality characteristics was measured, which is correlational with thesensory characteristics. The regression equation was made by stepwise regression: texture=1.448-3.256TBA+0.455fat content+4.52water activity (R~2=0.925). The regression equation wassignificant P＜0.01, and the degree of fitting was well. Flavor was not significantly different (P＞0.05)with nutritional quality characteristics.2. The appearances of the airing yak beef change significantly, the weight loss was76%, TBAvalue increased gradually with the prolonged process, the final product is0.48mg/kg; moisture contentand water activity decreased gradually, from raw meat to the fifth day, the moisture content change isnot significant (P＞0.05), other stages change significantly (P＜0.05), from the10th day to the15th dayis the major dehydration stage, the20th day and the25th day of water activity change significantly (P＜0.05); pH increased from5.40to5.52, a small range; total number of colonies on the5th day and the20th day change significantly (P＜0.05), coliform reduced gradually with the process,there were noListeria monocytogenes and Staphylococcus aureus detected. Conclusion: in the drying process, thereduction of water activity is the main reason for the decline of the total number of colonies, and lowerwater activity ensure the safety of products, The dehydration speed is the most important factoraffecting air-dry time and product crisp.3. There were eighteen kind of amino acid and fourteen kind of fatty acid in both yak meat andairing yak meat, the total content of amino acid and fatty acid in airing yak meat is higher than yakmeat(P＞0.05). The content of amino acid in airing yak meat was81.14g/100g dry matter, EAA/TAAwas39.45%，EAA/NEAA was65.15%. The total content of fatty acid was97.97%, P:S was0.32whichwas close to ideal pattern, n-6:n-3was1.4which was in the ideal range. So airing yak meat was a goodsource of high quality with unique flavor, and a kind of meat product with balanced fatty acid nutritionalvalue.4. Based on the response surface optimization analysis, it is determined that the optimal flavorformula is0.8%,0.73%and2.4%, for salt, sugar and cooking wine respectively, and the flavor scoresreached to7.96, closed to the level of quite likable.