## 3 Results
### Validation Experiment of Volatile Components Curve  
As shown in Table 4, each curve's predictions of the volatile components in the fifth hour were different, with the CPM having the highest accuracy, PCF having the second-highest accuracy and CSI having the lowest accuracy. PCF had the best prediction effect on heptanal (0.07) and the worst prediction effect on (E,E)-2,4-nonadienal (3.233). CSI was the best predictor of octanal (0.001), with negative predictions for (E,E)-2,4-nonadienal (\(-\)21.173), (E,E)-2,4-decadienal (\(-\)6.91), 1-octen-3-ol (\(-\)3.742) and (E)-2-nonenal (\(-\)45.821). The overall error of CPM was small, and the curve fitting was accurate. By comparison, it could be seen that CPM was more suitable for modelling and simulation of the key volatile compounds in the Maillard reaction of beef t \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{**No. Aroma-Active Compounds**} & \multirow{2}{*}{**RI a**} & \multicolumn{2}{c}{**Odor Threshold in**} & \multicolumn{5}{c}{**ROAV**} \\  & & \multicolumn{2}{c}{**Water (\#g/kg) b**} & \multicolumn{2}{c}{**MRPs A**} & \multicolumn{2}{c}{**MRPs B**} & \multicolumn{2}{c}{**MRPs C**} & \multicolumn{2}{c}{**MRPs D**} & \multicolumn{2}{c}{**MRPs E**} \\ \hline
1 & (E,E)-3,5-Octadien-2-one & 1068 & 0.1 & 0.007 & 0.010 & 0.016 & 0.009 & 0.010 \\
2 & Hexanal & 1087 & 0.0011 & 0.687 & 0.644 & 0.309 & 0.32 & 0.548 \\
3 & Heptanal & 1182 & 0.0009 & 1.066 & 1.252 & 1.369 & 1.848 & 2.394 \\
4 & 2-Pentyl-furan & 1235 & 0.019 & 0.244 & 0.153 & 0.156 & 0.046 & 0.113 \\
5 & p-Cresol & 1251 & 0.0084 & 0 & 0 & 0 & 0.092 & 0.039 \\
6 & Octanal & 1291 & 0.0004 & 3.48 & 6.801 & 3.929 & 5.023 & 6.876 \\
7 & Ethyl myristate & 1322 & 0.18 & 0.021 & 0.014 & 0.005 & 0.008 & 0.007 \\
8 & 2-Ethyl-3,5-dimethylpyrazine & 1346 & 0.00001 & 100 & 100 & 100 & 100 \\
9 & 2-Ethyl-6-methyl-pyrazine & 1371 & 0.04 & 0.007 & 0.008 & 0.021 & 0.029 & 0.037 \\
10 & Nonanal & 1395 & 0.0026 & 3.234 & 3.545 & 2.874 & 1.992 & 3.113 \\
11 & Trimethyl-pyrazine & 1402 & 0.033 & 0 & 0 & 0.013 & 0.017 & 0.026 \\
12 & (E)-2-Octenal & 1426 & 0.0027 & 1.359 & 3.286 & 2.11 & 1.475 & 2.013 \\
13 & 1-Octen-3-ol & 1438 & 0.0027 & 1.222 & 3.191 & 1.303 & 0.723 & 1.076 \\
14 & 3-(Methylthio)propanal & 1454 & 0.0014 & 0.298 & 1.083 & 0.214 & 0.69 & 1.047 \\
15 & Decanal & 1497 & 0.0026 & 0.352 & 0.466 & 0.124 & 0.35 & 0.409 \\
16 & (E)-2-Nonenal & 1531 & 0.00009 & 12.884 & 36.53 & 12.996 & 38.106 & 15.54 \\
17 & (E)-2-Octen-1-ol & 1544 & 0.04 & 0.032 & 0.055 & 0.057 & 0.034 & 0.025 \\
18 & 1-Octanol & 1559 & 0.022 & 0.032 & 0.056 & 0.029 & 0.049 & 0.048 \\
19 & Butanoic acid & 1631 & 0.004 & 0 & 0 & 0.017 & 0.23 & 0.015 \\
20 & Benzere acataldehyde & 1643 & 0.0017 & 5.564 & 3.462 & 0.96 & 3.818 & 2.818 \\
21 & (E)-2-Decenal & 1654 & 0.0027 & 0.457 & 1.162 & 0.536 & 0.636 & 0.644 \\
22 & (E,E)-2,4-Nonadienal & 1778 & 0.0002 & 3.285 & 11.567 & 2.277 & 1.807 & 0.686 \\
23 & (E)-2-Undecenal & 1861 & 0.044 & 0.029 & 0.066 & 0.026 & 0.039 & 0.036 \\
24 & (E,E)-2,4-Decadienal & 2001 & 0.0023 & 1.665 & 4.514 & 1.145 & 1.227 & 0.638 \\
25 & Phenol & 2020 & 0.046 & 0.009 & 0.008 & 0.002 & 0.004 & 0.004 \\
26 & Hexanoic acid & 2050 & 0.04 & 0.02 & 0.127 & 0.05 & 0.083 & 0.046 \\
27 & Heptanoic acid & 2130 & 0.022 & 0.005 & 0.006 & 0.003 & 0.004 & 0.006 \\
28 & Octanoic acid & 2264 & 0.0051 & 0.077 & 0.058 & 0.065 & 0.091 & 0.092 \\
29 & n-Decanoic acid & 2276 & 0.05 & 0.015 & 0.02 & 0.005 & 0.014 & 0.015 \\
30 & Nonanoic acid & 2370 & 0.02 & 0.027 & 0.017 & 0.018 & 0.023 & 0.031 \\ \hline \hline \end{tabular}  
* RIs were determined using a homologous series of n-alkanes on DB-WAX capillary columns; b odor thresholds were from the reference [(24)].  
\end{table} 
Table 3: Relative odor activity values of aroma-active compounds in MRPs. Figure 1: The result of sensory evaluation among MRPs. The values followed by different letters were significantly different (\(p\leq 0.05\)). Figure 2: The overall acceptability of MRPs.