Effect of Simulated Vibration and Storage on Quality of Tomato

: The inﬂuence of simulated transport vibration and storage conditions for 10 days on tomato fruits quality (color, weight, ﬁrmness, total soluble solids, and headspace gases) were investigated. Better kinetic models for color changes, weight loss, and ﬁrmness of stored tomato fruits were selected. Tomato fruits were divided equally into two main groups where the ﬁrst one was subjected to vibration at a frequency of 2.5 Hz for two hours and the other group was set as a control (with no vibration stress). Both tomato groups were stored for 10 days at 10 ◦ C and 22 ◦ C storage conditions. The results showed a reduction in total soluble solids, yellowness, weight, lightness in the tomato fruits subjected to vibration at 22 ◦ C storage condition. Ethylene and carbon dioxide increased by 124.13% and 83.85% respectively on the same condition (22 ◦ C). However, storage at 10 ◦ C slowed down the investigated quality changes attributes of both tomato groups (vibrated and control) during storage. The weight loss change kinetics of both tomato groups at both storage temperatures were highly ﬁtted with a zero-order kinetic model. Color and ﬁrmness kinetic changes of tomato groups stored at both conditions were described well by zero and ﬁrst order kinetic models. To validate the appropriateness of the selected model, lightness, redness, yellowness, and ﬁrmness were taken as an example. The study revealed that the vibration occurrence and increasing storage temperature cause various changes in the quality attributes of tomatoes.


Introduction
Tomato fruit (Lycopersicon esculentum, Mill) is one of the most common and significantly grown fresh produce worldwide and ranked second after potato in terms of area and amount of production as recently reported by Famuyİnİ and Sedara [1]. It is a vital source of nutrients and different beneficial minerals and considers as a source of income in most developing countries. The quality of any agricultural product is a significant factor for both the consumers and producers. The quality of tomatoes is highly categorized by weight, color, firmness, and flavor [2]. Tomatoes are climacteric fruits and their physiological attributes make them highly delicate agricultural products [3]. Wu and Technology Laboratory of Sultan Qaboos University, Oman. The selected samples (n = 63) were similar in color, size, weight (177 ± 0.02 g), firm state, and free of defects and blemishes. Tomato fruits were divided equally into two main groups where the first one was subjected to vibration at 2.5 Hz frequency for two hours and the other group stressed no vibration stress.
The vibrated group were exposed to vibration using an orbital shaker (model: SM25, Edmund Bühler GmbH, Schleswig-Holstein, Germany) [16] to simulate the vibration generated during fresh produce transportation at 2.5 Hz frequency for 120 min at a speed of 150 revolutions per minute (r/min) (205 km distance). The plastic container was tightly fixed in the top of the shaker and 3-axis vibration/acceleration data loggers (Model: OM-VIB101, Spectris plc, Connecticut, Norwalk, CT, USA) were placed vertically inside the container (bottom, middle and top) to record the generated vibration (every 1 s) during simulated transport from three different positions. The resulted vibration signals were later transformed to a personal computer and a shock application (Vibration data logger v2.3) was applied for time-domain vibration analysis of signals. Also, a histogram was used to identify the peaks number generated per accelerometer fixed on each location during the simulated transport experiment.
After conducting the simulated vibration experiment, tomatoes with and without vibration stress were divided equally into two groups at 22 ± 1 • C (65 ± 5% RH) and 10 ± 0.5 • C (95 ± 1% RH). Further objective evaluations of tomato fruit were carried out such as weight loss, firmness, color, total soluble solids (TSS), and headspace gases to study the influence of vibration/control treatments and two storage conditions on the quality of tomatoes at two days intervals for 10 days. For day-0 analysis, three tomato fruits with no vibration were analyzed for all previously mentioned analyses. Besides, daily observations of bruising were recorded. In the current paper, a total of 3 tomato fruits replicates were utilized for each treatment.

Weight Loss%
A batch of three tomato fruits for each treatment was weighed on day 0 and the weight loss percentage was recorded on days 2, 4, 6, 8, and 10, relative to day 0.

Color Measurements
The color values of tomato fruits were measured using a computer vision system ( Figure 1). A total of 5 readings were taken per sample for color measurements during the experiment at 2 days intervals (60 per day). The system includes a cardboard box utilized to cover the entire system and to avoid the backscattering effect. A lighting system including two long fluorescent lights (36 W) (Model: Dulux L, OSRAM, Milano, Italy) was placed above the sample at an angle of 45 • . An RGB digital camera (Model: EOS FF0D, Canon Inc., Tokyo, Japan) was fixed in the top of the cardboard box at 26 cm from the sample. The digital camera involves a remote shooting software EOS Utility used to acquire the image in the maximum required resolution. All captured images were transferred to a personal computer and stored in JPG format for subsequent analysis. ImageJ software (v. 1.53, National Institute of Health, Bethesda, MD, USA) was performed for image processing [6]. All obtained RGB values were transformed to CIEL*a*b* color coordinates. The L* value refers to darkness (0) and lightness (100), a* value is used to donate redness (+) and greenness (-), and the value of b* denotes yellowness (+) and blueness (-). The total color difference (TCD) (Equation (1)) from tomato samples was calculated. Chroma (Equation (2)), hue angle (Equation (3)), and tomato color index (CI) (Equation (4)) indicating color intensity, purity, and red color development index, respectively were also computed [26] as follow: Horticulturae 2021, 7, 417 4 of 20 color intensity, purity, and red color development index, respectively were also computed [26] as follow: Figure 1. A schematic diagram of computer vision system.

Firmness
To measure the force (N) needed to puncture the tomato surface, a digital fruit firmness tester (Model: FHP-803, L.L.C., Franklin, ME, USA) was used. Both sides were measured in each tomato sample at two days intervals.

Total Soluble Solids (°Brix)
Tomatoes juice was extracted and then analyzed by utilizing a digital refractometer (Model: PR-32 α, ATAGO Co., Ltd., Tokyo, Japan). Clear and pure drops of tomato juice were added to the prism surface of the refractometer and the readings were taken and expressed as °Brix.
2.2.5. Headspace Gases (CO2, O2, and C2H4) After the vibration treatment, eight plastic food containers (2.6 L) were prepared as gas collection containers. A total of 6 tomatoes (968.3 ± 25.2 g) were placed inside each

Firmness
To measure the force (N) needed to puncture the tomato surface, a digital fruit firmness tester (Model: FHP-803, L.L.C., Franklin, ME, USA) was used. Both sides were measured in each tomato sample at two days intervals.

Total Soluble Solids ( • Brix)
Tomatoes juice was extracted and then analyzed by utilizing a digital refractometer (Model: PR-32 α, ATAGO Co., Ltd., Tokyo, Japan). Clear and pure drops of tomato juice were added to the prism surface of the refractometer and the readings were taken and expressed as • Brix.

Headspace Gases (CO 2 , O 2 , and C 2 H 4 )
After the vibration treatment, eight plastic food containers (2.6 L) were prepared as gas collection containers. A total of 6 tomatoes (968.3 ± 25.2 g) were placed inside each container. Oxygen (O 2 ) and carbon dioxide (CO 2 ) concentrations were measured using O 2 /CO 2 analyzer (Model: 90 2D, Quantek Instruments, Inc., Grafton, Australia). Ethylene (C 2 H 4 ) (ppm) was determined using an ethylene detector (Model: SCS 56, Fricaval89, Valencia, Spain). Both instruments include a needle that is plunged inside the containers and an electronically timed pump used to pull the needed amount of gases for further analysis. Besides, two replicates were used per treatment to determine O 2 , CO 2 (%), and C 2 H 4 (ppm) inside the containers for two days intervals.

Kinetic Model
To determine the physical quality changes of vibrated and non-vibrated tomatoes stored at different storage temperature conditions as a function of time, a kinetic model was applied. The rate of quality change factor was explained by (Equation (5)) [27]: where k is the kinetic rate constant at a temperature T, C is the quality factor concentration at time t, and n is the order of the reaction. Most time-dependent relationships for most food materials are likely to be well fitted with the zero-order kinetic model (Equation (6)) or the first-order kinetic model (Equation (7)) follow [28]: where C 0 is the initial quality parameter value, C is the quality parameter value at a time and t is the time of storage. Regression analysis such as reduced chi-square (X 2 ) (Equation (8)), determination of coefficient (R 2 ) (Equation (9)), and root mean square error (RMSE) (Equation (10)) were done as the main standard to choose the best fit of the studied kinetic models to the current experimental data. Also, the model that effectively fitted tomato fruits quality parameters was defined with the maximum R 2 and lowest X 2 and RMSE. Besides, the following formulas were applied for the estimations of the parameters [23]: where, MR pre , i and MR exp , i are the ith predicted and experimental values of the quality parameters and MR pre is the average values of predicted quality parameters, n is the numbers of constant model and N is the number of observations. To validate the appropriateness of the selected model, some quality attributes were taken as an example.

Statistical Analysis
SPSS 20.0 (International Business Machine Crop., New York, NY, USA) was applied to study the influence of vibration/control treatments as well as storage temperature conditions (10 • C and 22 • C) on the physical and physiological attributes of tomatoes for 10 days. For statistical analysis, analysis of variance (ANOVA) was conducted at a 5% significance level. All resulted data were expressed in mean ± SD.

Simulated Vibration Analysis
The accelerometers placed in the three positions of the plastic container recorded thousands of vibration signals. Histogram analysis was applied for all time-domain vibration signals to obtain the peaks number of accelerations per accelerometer ( Table 1). The middle position recorded the maximum number of peaks (1664 peaks) at 2.5 Hz for 120 min in the acceleration interval of 0.0275 to 0.0280 m/s 2 with an acceleration occurrence reached 22.75%. This was followed by the bottom position of the container which generated 1248 peaks in the acceleration interval of 0.0053 to 0.0055 m/s 2 . The acceleration interval of 0.0151 to 0.0156 m/s 2 of the top position recorded 896 peaks during the simulated transport experiment. The vibration recorded from each position of the tomato plastic container can indicate that tomato fruits can encounter several damages from each side of the packaging unit during transportation. Figure 2 shows the weight loss (%) of both tomato groups stored at different storage conditions (10 and 22 • C) during the 10 days of storage. Tomato fruit weight loss was varied significantly (p < 0.05) between vibrated and control groups. Also, tomato weight loss was statistically influenced (p < 0.05) by storage condition and storage duration. Vibrated tomato fruits stored at ambient temperature (22 • C) had about 4.21% weight loss at the end of storage compared to the control tomato group that had 3.38% of weight loss at the same storage condition. The lowest tomato weight loss was recorded on the control group stored at 10 • C with 1.02% on day 10 of storage. While the vibrated tomatoes stored at 10 • C recorded a 1.39% weight loss on the last day of the study. As reported by Jung et al. [11], vibration can accelerate the increment of both respiration and ethylene rates resulted in a higher reduction in moisture content of the produce, consequently increasing weight reduction as storage duration increased. As stated by Xu et al. [13], vibration can prompt the process of ripening which is highly caused by the promotion of respiration rate and ethylene production. During ripening, an increase in weight loss can be observed due to water movement (water evaporation) from the produce to the surrounding environment. Also, Munhuewyi [29] confirmed that the rate of respiration is one of the main factors that contribute to weight alterations in fresh produce due to the conversion of carbon (C) atoms to atmospheric carbon dioxide (CO 2 ).   Figure 3 shows the significant (p < 0.05) interaction effect of treatment tion/control groups), storage conditions, and storage duration on tomato L* val storage time, a decreasing trend of the L* value of all vibrated and non-vibrated t at both storage temperatures for the 12 days storage was observed due to a redu   [30] also recorded higher weight loss on tomato fruit stressed to vibration compared to the control tomato group due to higher respiration rate and mechanical damages caused by the simulated transport vibration. According to Endalew [31] and Al-Dairi et al. [6], storage at ambient temperature resulted in a greater transpiration rate that leads to wilting, shriveling, and weight reduction in tomatoes. Also, Al-Dairi et al. [2] recorded a low weight loss percentage (3.18%) on tomato fruit stored for 12 days at low temperature (10 • C) which attributed to water retention that occurred at this condition. Regarding weight loss kinetic, Table 2 demonstrates that the zero-order kinetic model gave the highest R 2 (R 2 ≥ 0.9483) and the lowest values of X 2 , and RMSE for weight loss of both control and vibrated tomato groups stored at both storage conditions (10 • C and 22 • C).  Figure 3 shows the significant (p < 0.05) interaction effect of treatments (vibration/control groups), storage conditions, and storage duration on tomato L* value. With storage time, a decreasing trend of the L* value of all vibrated and non-vibrated tomatoes at both storage temperatures for the 12 days storage was observed due to a reduction in brightness. However, the results of this study showed a higher L* value reduction (37.33) in tomato stressed to vibration compared to the control 39.83 group and stored at 22 • C. Besides, the non-vibrated tomatoes at 10 • C had a better (L*) color value (46.71) than tomatoes stressed to vibration after 10 days of storage. More changes of lightness were observed on tomatoes exposed to vibration due to the repeated vibration motions generated during simulated transport. Besides, the reduction of the color change of the L* value with storage time particularly at 22 • C is due to carotenoids synthesis which leads to tomato darkening [2]. Discoloration of fresh produce due to vibration results in enzymatic browning [32] like polyphenol oxidase (PPO) and peroxidase (POD) [33]. Lightness (L*) change kinetics on Table 2 shows that the zero-order model produced a high R 2 for both control (R 2 = 0.9483) and vibrated (R 2 = 0.9720) tomato groups stored at 10 • C. However, the first-order model was considered the most appropriate model to represent the L* value change for 10 days for both tomato groups stored at 22 • C. To validate the best model of the L* value of both tomato groups stored at both temperature conditions, the predicted values with the experimental data values were presented and plotted in Figure 4. The predicted values were in a very good correlation with the experimental values (R 2 > 0.94) where the predicted data banded around the straight line for all storage conditions and groups which validate the suitability of the selected.     The redness (a*) was differed (p < 0.05) significantly between tomato groups (control and vibrated), storage condition, and storage duration. The redness increased dramatically as storage temperature and duration increased. Besides, vibration showed a higher The redness (a*) was differed (p < 0.05) significantly between tomato groups (control and vibrated), storage condition, and storage duration. The redness increased dramatically as storage temperature and duration increased. Besides, vibration showed a higher a* value increment in tomatoes than those exposed to no-vibration. At the end of the 10 days storage period at 22 • C, the a* value percentage of increase in tomato stressed to simulated vibration was 54.14%, while it was 38.66% in tomatoes with no vibration ( Figure 5). However, the control tomato group stored at 10 • C showed the lowest percentage of increase in both groups. The increment in redness observed on vibrated tomato samples could be attributed to the high percentage of acceleration occurrence generated from simulated transport resulted in increasing the ripening process of the samples. Besides, higher ethylene and respiration are responsible for vibrated tomato color changes. Also, Dagdelen and Aday [32] indicated an increase in the a* value of peach on the last day of storage due to the increase in respiration rate resulted from the mechanical vibration leading to fruit and color degradation. Wu and Wang [4] observed high red color development in tomatoes exposed to 60 min of simulated transport vibration. Furthermore, high temperature caused a rapid change in the redness value due to lycopene accumulation, rapid ripening, and chlorophyll degradation compared to low storage temperature with storage time [34]. The experimental data of a* value color kinetic of vibrated and control tomato groups stored at 10 • C was highly described by the first-order model. The zero-order kinetic model provided the highest (R 2 ) for the a* value of vibrated and control tomato groups stored at 22 • C Table 2. The good agreement reported between the predicted values and the experimental values can validate the appropriateness of the models in a* value color kinetic change ( Figure 6). ripening, and chlorophyll degradation compared to low storage temperature with storage time [34]. The experimental data of a* value color kinetic of vibrated and control tomato groups stored at 10 °C was highly described by the first-order model. The zero-order kinetic model provided the highest (R 2 ) for the a* value of vibrated and control tomato groups stored at 22 °C Table 2. The good agreement reported between the predicted values and the experimental values can validate the appropriateness of the models in a* value color kinetic change ( Figure 6).  The yellowness (b*) color from the two tomato groups decreased with storage temperature and storage period and a considerable b* value difference (p < 0.05) between the vibrated and control tomato groups was observed (Figure 7). On the last day of storage, vibrated tomato stored at 22 °C showed 18.35% more b* value reduction than the control group tomato stored at 10 °C that had the lowest reduction in the b* value among all tomato groups stored at both conditions. Endalew [31] recorded a reduction in the b* value of tomato at a higher temperature during storage due to red color increment. Table 2  The yellowness (b*) color from the two tomato groups decreased with storage temperature and storage period and a considerable b* value difference (p < 0.05) between the vibrated and control tomato groups was observed (Figure 7). On the last day of storage, vibrated tomato stored at 22 • C showed 18.35% more b* value reduction than the control group tomato stored at 10 • C that had the lowest reduction in the b* value among all tomato groups stored at both conditions. Endalew [31] recorded a reduction in the b* value of tomato at a higher temperature during storage due to red color increment. Table 2 shows that the b* value of control tomato groups stored at 10 • C and 22 • C was highly described by the zero-order model. However, the first-order kinetic model was adequately fitted with the b* value of vibrated tomato stored at 10 • C and 22 • C. Figure 8 indicated the correct selection of the kinetic models in the b* color kinetic change which was resulted from the good agreement and relation between the predicted and the experimental data values.   The color attributes of total color difference (∆E), chroma, hue angle, and tomato color index were significantly (p < 0.05) varied with storage temperature condition and duration ( Figure 9). Also, they were statistically (p < 0.05) differed between control and vibrated tomato groups, except with chroma, which had no pronounce (p > 0.05) significance between the tomato groups (vibrated and control). The total color difference value of tomato increased with storage time in all storage conditions and groups. The highest ∆E was observed in vibrated tomato group (22.87) followed by the control tomato group (17.86) stored at 22 • C ( Figure 9A). On the last day of storage, the ∆E reached 15 and 11.16 on vibrated and control tomato groups stored at 10 • C, respectively ( Figure 9A). The reduction in the hue • was higher in tomatoes exposed to vibration and stored at 22 • C with 54.99% than those exposed to no vibration at 10 • C ( Figure 9B). Storage at 22 • C offered a faster reduction in hue angle caused due to the natural relation between chemical reactions and temperature that make tomato samples ripen rapidly and convert the green color of tomato to red [5]. During storage days, a fluctuation in chroma value was observed in tomato groups, particularly in those stored at 10 • C ( Figure 9C). Despite this, the vibrated tomato group stored at 22 • C showed a dramatic increase in chroma for the 10 days storage period ( Figure 9C). As tomato is exposed to vibration and stored at a higher temperature, more color index (CI) can be observed. The initial color index of tomato was 1.03 which later increased and reached 1.91 and 1.71 in vibrated and control tomato groups stored at 10 • C, respectively ( Figure 9D). However, the increment was twice higher at 22 • C in the vibrated (2.29) and control (2.24) tomato groups ( Figure 9D).  The color attributes of total color difference (∆E), chroma, hue angle, and tomato color index were significantly (p < 0.05) varied with storage temperature condition and duration ( Figure 9). Also, they were statistically (p < 0.05) differed between control and Regarding model kinetics, Table 2 shows that the total color difference and tomato color index experimental data of all tomato groups stored at both storage conditions were better predicted by the first-order kinetic model. However, the zero-order model was found suitable to describe chroma and hue angle data of the control tomato group stored at 10 • C. To predict the kinetic changes in hue angle and chroma of vibrated tomato stored at both conditions and control tomato group at 22 • C, a zero-order model was selected (Table 2).

Firmness (N)
There was a significant difference (p < 0.05) in the firmness values between vibrated and control tomato groups. Besides, storage temperature conditions and storage duration were highly significant (p < 0.05) with firmness ( Figure 10). The initial value of firmness in all tomato groups was 35.51 N. With storage time, the firmness reduced by 24% and 21.95% on vibrated and control tomato groups stored at 10 • C, respectively. When the vibrated and control tomatoes were stored at 22 • C, their firmness state became low with increasing storage duration. At the end of storage, tomatoes subjected to 2 h vibration and stored at 22 • C showed more reduction (44.82%) in firmness compared to those stressed no vibration (35.11%). As highlighted by Wei et al. [7], the vibration generated from simulated transport accelerated the ripening process, thus, reduced firmness with storage time. Dagdelen and Aday [32] reported that higher vibration during transportation can cause more damage to the produce cell wall, therefore, water loss and respiration increased due to structural degradation. In this study, firmness loss was observed in both control and vibrated tomato groups particularly at a storage temperature of 22 • C. This was attributed to the enzymatically controlled processes occurred at room temperature condition which is also link to other metabolic processes like respiration and transpiration as obtained by Cherono and Workneh [35]. Kabir et al. [21] and Al-Dairi et al. [36] found similar trends of firmness reduction at cold and ambient temperature conditions. served in tomato groups, particularly in those stored at 10 °C ( Figure 9C). Despite this, the vibrated tomato group stored at 22 °C showed a dramatic increase in chroma for the 10 days storage period ( Figure 9C). As tomato is exposed to vibration and stored at a higher temperature, more color index (CI) can be observed. The initial color index of tomato was 1.03 which later increased and reached 1.91 and 1.71 in vibrated and control tomato groups stored at 10 °C, respectively ( Figure 9D). However, the increment was twice higher at 22 °C in the vibrated (2.29) and control (2.24) tomato groups ( Figure 9D).  The zero-order kinetic model was successfully fitted to experimental data of firmness reduction values of both vibrated to control tomato groups stored at 10 • C (Table 2). However, the first-order model gave the highest coefficient of determination (R 2 ) and low chi-square (X 2 ), and root mean square error (RMSE) of the firmness value of vibrated and non-vibrated tomatoes stored at room condition as shown in Table 2. Figure 11 illustrates the efficiency of the selected models. The straight line was banded by the predicted values of all tomato groups stored at both storage conditions. This can validate the suitability of the model chosen for this parameter.

Total Soluble Solids ( • Brix)
The amount of total soluble solids (TSS) was increased significantly (p < 0.05) with storage time and storage conditions. Also, it was varied statistically (p < 0.05) between the tomato groups ( Figure 12). A higher magnitude of TSS increment was observed in tomatoes exposed to two hours vibration (4.70 • Brix) than in the non-vibrated one (4.48 • Brix) where the increase accelerated by storage at 22 • C. The increase in TSS was also observed in vibrated and control tomatoes stored at 10 • C with 4.51 • Brix and 4.41 • Brix, respectively. Increasing TSS in tomatoes with simulated vibration stress compared to control tomatoes is owing to the rapid ripening of stressed tomatoes under these conditions. During storage, TSS increased more rapidly, suggesting a more ripening resulted in pectin substance degradation into more simple sugars e.g., Oligosaccharides [29]. More TSS was observed on samples subjected to vibration compared to the control samples by Dagdelen and Aday [32]. Similar results of significance on TSS between control and vibrated samples were also found on apples by Jung and Park [9]. A similar trend was observed by Kabir et al. [21] and Pathare and Al-Dairi [37], where increasing storage time can increase TSS contents. of fresh produce. Besides, Tigist et al. [34] recorded higher TSS content after the 32 days of storage at room temperature. and control tomato groups. Besides, storage temperature conditions and storage duration were highly significant (p < 0.05) with firmness ( Figure 10). The initial value of firmness in all tomato groups was 35.51 N. With storage time, the firmness reduced by 24% and 21.95% on vibrated and control tomato groups stored at 10 °C, respectively. When the vibrated and control tomatoes were stored at 22 °C, their firmness state became low with increasing storage duration. At the end of storage, tomatoes subjected to 2 h vibration and stored at 22 °C showed more reduction (44.82%) in firmness compared to those stressed no vibration (35.11%). As highlighted by Wei et al. [7], the vibration generated from simulated transport accelerated the ripening process, thus, reduced firmness with storage time. Dagdelen and Aday [32] reported that higher vibration during transportation can cause more damage to the produce cell wall, therefore, water loss and respiration increased due to structural degradation. In this study, firmness loss was observed in both control and vibrated tomato groups particularly at a storage temperature of 22 °C. This was attributed to the enzymatically controlled processes occurred at room temperature condition which is also link to other metabolic processes like respiration and transpiration as obtained by Cherono and Workneh [35]. Kabir et al. [21] and Al-Dairi et al. [36] found similar trends of firmness reduction at cold and ambient temperature conditions. The zero-order kinetic model was successfully fitted to experimental data of firmness reduction values of both vibrated to control tomato groups stored at 10 °C (Table 2). However, the first-order model gave the highest coefficient of determination (R 2 ) and low chi- square (X 2 ), and root mean square error (RMSE) of the firmness value of vibrated and nonvibrated tomatoes stored at room condition as shown in Table 2. Figure 11 illustrates the efficiency of the selected models. The straight line was banded by the predicted values of all tomato groups stored at both storage conditions. This can validate the suitability of the model chosen for this parameter.

Total Soluble Solids (°Brix)
The amount of total soluble solids (TSS) was increased significantly (p < 0.05) with storage time and storage conditions. Also, it was varied statistically (p < 0.05) between the tomato groups ( Figure 12). A higher magnitude of TSS increment was observed in tomatoes exposed to two hours vibration (4.70 °Brix) than in the non-vibrated one (4.48 °Brix) where the increase accelerated by storage at 22 °C. The increase in TSS was also observed

Headspace Gases
Headspace O2 and CO2 concentration significantly (p < 0.05) declined over time at both storage temperatures. Headspace O2 was not varied significantly (p > 0.05) between the vibrated and non-vibrated groups Table 3. The average O2 concentration on day 2 was almost 16.85% and 16% in the control and vibrated stress group which reduced to reach 14.35% and 15.15% at 10 °C on day 8 respectively. More reduction was reported on O2% in the control and vibrated tomato groups stored at 22 °C. On day 8, the vibrated tomato group showed a reduction in O2 with 7.80% which later increased by 1% on day 10. Furthermore, more CO2 increment was observed in tomatoes stored at 22 °C. On day 8, the CO2 content reached 4.75 and 17.30% on the vibrated and control tomato groups respectively at 10 °C, while it was 4.55 and 17.75% respectively at 22 °C. The study suggested that both O2 and CO2 gases are correlated inversely during storage inside the gas collecting containers of tomatoes.
A significant increase was observed in ethylene (C2H4) at both storage conditions for 8 days storage period, which reduced on day 10 in all storage temperatures. There was no pronounce significance (p < 0.05) in C2H4 content between the vibrated group and the control tomato group. However, the vibrated tomatoes stored at room temperature recorded the highest content in C2H4 on day 8 with 3.25 ppm followed by the control tomatoes stored with 1.85 ppm compared to the initial value (1.45 and 1.25 ppm) respectively. Ethylene concentrations were 1.26 and 1.55 ppm in the control group and vibration stress group stored at 10 °C on day 8 respectively. All gases reached their equilibrium concentration on day 8 (Table 3). Low O2 concentration activates anaerobic metabolites. The slow change in O2 at 10 °C could result from the low rate of respiration at low-temperature storage conditions. Besides, the C2H4 production increased due to the continued ripening even after harvest. Therefore, C2H4 can accelerate the ripening of fresh produce [9].

Headspace Gases
Headspace O 2 and CO 2 concentration significantly (p < 0.05) declined over time at both storage temperatures. Headspace O 2 was not varied significantly (p > 0.05) between the vibrated and non-vibrated groups Table 3. The average O 2 concentration on day 2 was almost 16.85% and 16% in the control and vibrated stress group which reduced to reach 14.35% and 15.15% at 10 • C on day 8 respectively. More reduction was reported on O 2 % in the control and vibrated tomato groups stored at 22 • C. On day 8, the vibrated tomato group showed a reduction in O 2 with 7.80% which later increased by 1% on day 10. Furthermore, more CO 2 increment was observed in tomatoes stored at 22 • C. On day 8, the CO 2 content reached 4.75 and 17.30% on the vibrated and control tomato groups respectively at 10 • C, while it was 4.55 and 17.75% respectively at 22 • C. The study suggested that both O 2 and CO 2 gases are correlated inversely during storage inside the gas collecting containers of tomatoes.
A significant increase was observed in ethylene (C 2 H 4 ) at both storage conditions for 8 days storage period, which reduced on day 10 in all storage temperatures. There was no pronounce significance (p < 0.05) in C 2 H 4 content between the vibrated group and the control tomato group. However, the vibrated tomatoes stored at room temperature recorded the highest content in C 2 H 4 on day 8 with 3.25 ppm followed by the control tomatoes stored with 1.85 ppm compared to the initial value (1.45 and 1.25 ppm) respectively. Ethylene concentrations were 1.26 and 1.55 ppm in the control group and vibration stress group stored at 10 • C on day 8 respectively. All gases reached their equilibrium concentration on day 8 (Table 3). Low O 2 concentration activates anaerobic metabolites. The slow change in O 2 at 10 • C could result from the low rate of respiration at low-temperature storage conditions. Besides, the C 2 H 4 production increased due to the continued ripening even after harvest. Therefore, C 2 H 4 can accelerate the ripening of fresh produce [9].

Subjective Quality Analysis/Visual Observation of Mechanical Damage
The visual observation of the physiological damage and bruise incidence was mostly observed on the vibration stress tomato group at 22 • C ( Figure 13) compared to the control group stored at both storage conditions. The damage on vibrated tomato at 22 • C reached 38.80%, while it was 5.50% on the control tomato group at the same temperature. No dam-age was observed on the control tomato stored in both conditions. Overall, the results of this study showed that vibration stress during simulated transport and storage at ambient accelerated the degradation of tomato with storage time.

Subjective Quality Analysis/Visual Observation of Mechanical Damage
The visual observation of the physiological damage and bruise incidence wa observed on the vibration stress tomato group at 22 °C ( Figure 13) compared to th group stored at both storage conditions. The damage on vibrated tomato at 22 °C 38.80%, while it was 5.50% on the control tomato group at the same temperature. N age was observed on the control tomato stored in both conditions. Overall, the r this study showed that vibration stress during simulated transport and storage at accelerated the degradation of tomato with storage time.

Conclusions
The study investigated the effect of vibration stress generated from laboratory simulated transport and storage at two different storage conditions on the quality of tomatoes (weight loss %, color parameters, firmness, total soluble solids (TSS), and headspace gases) for 10 days. Based on the obtained results, weight loss %, firmness, lightness (L*), redness (a*), yellowness (b*), hue • , and total color changes (∆E) were highly dependent on all studied factors (storage duration, vibration, and storage temperature conditions). A high reduction in weight, L*, b*, firmness, O 2 and hue angle, and increment in a*, TSS, color index (CI), C 2 H 4 content, and CO 2 in the vibrated tomato fruits at room temperature 22 • C. Storage at low temperature (10 • C) reduced the quality changes occurrence of both control and vibrated tomato groups. The experimental data of weight loss, color, and firmness values were highly fitted to zero and first-order kinetic models. It was also found that the first-order kinetic model was the best model applied to represent the quality changes kinetic of both tomato groups at 10 and 22 • C. Proper technologies during transportation and storage are required to minimize the quality changes and degradation of tomatoes in the harvesting-consumption system.