Analysis Of Beef Flavor Compounds And Exploration Of The Novel Detection Method

As a delicious and rich nutrients food,beef products possess both nutritional and edible value.It comes as no surprise the beef is widely welcomed by domestic and foreign consumers and the beef quality has become the focus of widespread concern.The beef quality mainly includes tenderness,flavor,water-holding capacity,juiciness and flesh color.Beef flavor is an important aspect of beef quality,which has directly impact on the nutritional,edible and commercial value of beef.Beef flavor is a combination of taste and odor.The study of beef flavor is benefit for tracking the the source of beef flavor components.Besides,it can provide important guidance for eliminating bad smells,producing high-grade beef,beef spices and fragrances.The main evaluation methods of flavor are mainly sensory evaluation and instrumental evaluation.However,organizing and operating a sensory evaluation program is very complicated and the results of sensory evaluation may be affected by physiological and psychological factors.The instrumental evaluation can come over the disadvantages of sensory evaluation.This paper designed a taste sensor array to evaluate the beef taste quality,and the mathematical model between sensor array results and the sensory evaluation results are built to evaluate the beef taste quality rapidly,objectively and accurately.The main research work is as follows:1.Headspace solid-phase microextraction(HS-SPME)is commonly used to analyze and detect volatile fragrant components in foods.Firstly,the conditions of HS-SPME are optimized as the 75 μm CAR/PDMS extraction head,under the following conditions:extraction temperature at 80 oC,extraction time = 50 min,and desorption time = 2 min.The volatile flavor substances in different parts of cooked beef and raw beef were investigated by the methods above.There are 38 volatile compounds(10 hydrocarbons,7alcohols,4 aldehydes,8 acids,6 ester,1 ketone,2 furan,sulfur and others)in raw beef.There are 49 volatile compounds(10 hydrocarbons,5 alcohols,20 aldehydes,3 acids,1ester,6 ketone,4 furan,sulfur and others.)in cooked beef.2.Amino acids and 5’-nucleotides(5’-IMP and 5’-GMP)are the most important taste compounds and they were detected in this study.Using amino acid automatic analyzer and high performance liquid chromatography detected amino acids and 5’-IMP,5’-GMP,respectively.By analyzing essential amino acid(EAA),nonessential amino acid(NEAA),total amino acids(TAA),we evaluated the nutritional value of beef.The taste value(TAV)of different taste substances was calculated to evaluate the contribution of different tastesubstances to beef flavor.The results showed that beef was a high quality protein source with good flavor and nutrition.3.A rapid,objective and accurate evaluation method based on sensor array was explored.According to the principle of Beidler on taste,we built a taste sensor array to collect the different signals from samples.Before examination,the working electrodes sensitive parts was activated in relevant activation fluid and soaked in deionized water for15 min.The working electrodes were confirmed to be stable before detecting samples.The taste signals can be converted to voltage signals by the electrochemical workstation.Using principal component analysis(PCA)to reduce the dimensionality of data.The top 5components have extracted and its accumulated contribution of 83.998%.BP artificial neural networks(BP-ANN),Support Vector Machine(SVM)and Bayesdiscriminant were used to build models between sensor array results and the sensory evaluation with accuracy rate of 90%、86.2%、92.3%.So support vector machine(SVM)was finally selected to achieve rapidly,objectively,and accurately evaluation of beef taste quality.