# The Plasma Ozonizer System for Mangosteen Storage Container to Preserve the Quality of Mangosteen
## 4 Discussion
### Assessment of the Quality and Sensory Evaluation  
Ozone can extend shelf life by oxidizing the ethylene gas produced during mangosteen's respiration process [35]. In addition, the ethylene production correlated well with the color changes of mangosteen. Therefore, ozone affected the mangosteen fruit's color during storage.  
In this study, when the mangosteen fruit ripened, the lightness (L*) values in the skin declined. Compared to the control treatment, the rate at which the L* values decreased during the ozone treatment slowed. L* values decreased, indicating a darkening of the surface, which might be explained by the increased anthocyanin content.  
Because chlorophyll is degraded in control fruits, the values of b* and a* change more rapidly, enabling other pigments' colors to be observed. Through this process, the color green transforms into other colors, including yellow, pink, red, and purple, and finally into black. Anthocyanin pigments cause skin discolorations to turn reddish-yellow depending on their concentration [15]. Treatments with ozone had an impact on the content of anthocyanin. Anthocyanin content typically declined as ozone levels and treatment time increased [36]. It has been suggested that applying ozone to fruit during storage can prevent fruit skin color from changing.  
Fruits under the ozone treatment lost significantly less weight than fruits in the control treatment. Throughout the process of preserving mangosteen, water loss occurs. As a result, mangosteen fruit weight decreases. The rate of water loss is influenced by the rate of respiration, temperature fluctuation, and relative humidity levels [17]. The ozone treatment's reduced weight loss may be caused by the structure of the inhibition of respiration rate [37; 38].  
The firmness of the pericarp is a crucial fruit feature because it is used by many consumers to assess the mangosteen's quality. At the end of the storage day, a comparison between the control treatment and the ozone treatment shows that the pericarp firmness of the mangosteen significantly increased while the weight loss percentage decreased. Fruit firmness varies during ripening and storage as a result of protopectin being converted to pectin [17]. The peel of mangosteen fruits, which also contains pectin, phenolic acid, tannin, xanthone, and anthocyanins, is the most significant component [39]. Oxidation caused by ozone has the possibility of adversely influencing pectin's activities.  
The primary factor influencing consumer preference and determining whether a product is accepted or rejected is the mangosteen's external appearance. In all evaluation parameters, the sensory score of fruit treated with ozone was higher than the control group. Our results demonstrate that ozone has a longer shelf life while having no negative effects on the quality of the harvested fruit. Ozone treatments have been shown in various studies to be an alternate approach for extending the shelf life of fruits and vegetables while preserving the sensory quality, such as fresh strawberries [17] and papaya [18].