Research On Commercial Quality And Assessment Technology Of Yak Meat

Yak as the special livestock resource of Qinghai-Tibet Plateau, is an important tool and main economicsources of production and living. Yak meat is the most value-added product, so its security qualitycultural affect Qinghai-Tibet Plateau community even people around the world. Analyzing otherpeople’s research about Yak meat, we found that previous studies ignored the feeling of consumer toYak meat. The physiochemical indexes were used to evaluate Yak meat eating qualities by constructingregression models scientifically, taking the fried meat as an example. Specific research are as follows:(1) The indicators of fried Yak meat eating quality was screened by M value method, principalcomponent analysis and correlation analysis coupled with sensory evaluation accordingGB/T16861-1997. It was concluded that the texture characteristics played an important role asevaluating Yak meat, which comprised hardness tenderness and springing. Besides flavor andappearance also were used to evaluate Yak meat, which comprised fragrance taste acid and colorbrightness respectively. The indicators made up the sensory evaluation system of Yak meat.(2) In order to use instruments instead of sensory evaluation and reduce subjective error of sensoryevaluation, the correlation analysis and regression analysis were used to develop model of sensoryevaluation indicators and the results of instrumental indicators(P<0.05). The regression equationsestablished had better fitting effects (R2>0.6), except for hardness and acid. Model validation showedthat the equations had high accuracy to instead sensory evaluation. By reason of shear force hadsignificant correlation with several sensory evaluating indicators, Yak meat was divided into threegrades based on the variance analysis of shear force: first grade, shear force≤5.3kg, tender; second grade,shear force5.3kg~7.6kg, general; third grade, shear force＞7.6kg older.(3) The experiment measured shear force and scanned spectrometer of340samples at the same time,using near infrared spectrum technology to build prediction model of shear force. The maximum valueof shear force was16.2kg, the minimum was2.4kg, and the average was6.90±2.67kg. Resultsshowed that RPD was lower than2.5, RER was lower than7.0of all the built models. So the models ofshear force need were not good enough and need further research.(4) Given the large proportion of older meat, it was necessary to improve Yak meat quality by aging.Yak meat were placed under2and10℃respectively after hot-boning and vacuum packing. pH, shearforce, cooking loss and meat color were measured at1,2,3,4,6,12,18d during postmortem aging, tostudy the effect of time and temperature on quality of yak meat. Results showed: from1to12d pH ofmeat under2℃kept rising, while meat under10℃changed little, then both of them decrease during12~18d. Yak meat became tender with extend of post aging time, but shear force of10℃significantlylower than meat of4℃. L*, a*, b*, C*, h had overall risong trend during post aging. Generallyconcluded that, yak meat from hot-boning and vacuum packing reached first grade placed under2℃after18days’ post aging, and it needed shorter time placed under10℃.