## 3 Results
The rise of rejections, which is more apparent at high temperature levels, was due to the degradation of thermosensitive nutrients such as vitamin C and others that lead to degradation of sensory characteristics such as aroma, flavor and taste [22; 23; 24]. The data in Table 5, which presents the comparison between the sensory and the microbiological shelf life, show that the sensory shelf life corresponds to 12, 5.3, 2.6 and 2.0 days (Temperature levels: 10, 20, 30, 40 \({}^{\circ}\)C), all of which were lower compared to the microbiological shelf life: 15.1, 6.6, 3.6 and 3.1 days (exponential model), and 16.4, 7.2, 4.5 and 3.2 days (polynomial model) [17]. This deviation was mainly due to the more rapid degradation kinetics of enzymatic reactions than that of microbiological components. This means basically that the juice maybe presented unwanted sensory characteristics within its microbiological shelf life. This is very important for the industry because if they take into account both microbiological and sensory shelf life while adjusting the expiration date of the pasteurized orange juice, they will minimize returned products. More specifically, off-flavors and unwanted aromas of orange juice are mainly attributed to the generation of 4-vinylguaiacol (4 VG) after prolonged storage at higher temperatures [25]. According to the work of [PERSON] et al. (2022) [26], which assessed the most prominent types of off-flavor and off-taste chemical compounds that were generated during long-term storage of orange juice at high temperatures, four compounds and more specifically dimethyl sulphide, 4-vinylguaiacol, \(\alpha\)-terpineol and furaneol were identified. Table 6 provides information on the shelf life of juices and more specifically on the median shelf life (h) per temperature level, including also the 95% confidence intervals and the quartiles of the median. The log-rank and Kruskal-Wallis test of homogeneity between temperature levels showed strong statistical significance (\(p<0.0001\)) (Table 7), indicating different median survival times, and judging by the size of the overlap of both the quartiles and the confidence limits, a survival decrease at the levels: 10 \(>\) 20 \(>\) 30 = 40 is apparent (in the last two temperature levels, the confidence limits of survival overlap significantly). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Temperature** & **Failures** & **Passes** &
\begin{tabular}{c} **Median** \\ **Time (h)** \\ \end{tabular} & **Days** & **SE** \\ \hline
10 & 35 & 31 & 287.9 & 12 & 13.8 \\
20 & 38 & 26 & 126.8 & 5.3 & 6.0 \\
30 & 39 & 29 & 63.0 & 2.6 & 3.0 \\
40 & 43 & 23 & 48.2 & 2.0 & 2.7 \\ Combined & 155 & 109 & 168.9 & & 9.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Survival time (h) at different temperature levels using the Kaplan–Meier estimator. The analytical survival rate of orange juice data (Table 8) indicated the shelf life and the survival rate per temperature level. The term \"pass\" and \"failure\" correspond to the \"acceptance\" or \"rejection\" of a sample. So, depending on the rejection rate that a company considers acceptable, the corresponding shelf life can be calculated. Thus, if the firm considers the minimum acceptance rate for its product to be around 50% (e.g., 50% of the consumers will reject the product) the predicted sensory shelf life (h) is: 312 h at 10 \({}^{\circ}\)C (44.2% failure), 120 h at 30 \({}^{\circ}\)C (46.83% failure), 60 h at 30 \({}^{\circ}\)C (39.2%) and 50 h at 40 \({}^{\circ}\)C (51.6%). In the study of [PERSON] et al. (2016) [16], where strawberry juice was stored at different temperature levels, it was shown that for an acceptance rate 50% the predicted sensory shelf life (h) was -2016, -1344, -672, -336 for 20, 28, 38 and 42 \({}^{\circ}\)C. Although direct comparison with the results of the present study was not adequate due to the differences between the products, it was observed that in both experiments increasing storage temperature reduces by half the time needed for the consumers to perceive sensory defects.