Sumary
Citrus are the most widely produced fruits and their market has increased in recent years favoured by their high content in vitamin C and other bioactive compounds, such as polyphenolic compounds, with high antioxidant properties. Nowadays new innovative environmentally friendly postharvest technologies are been studied to commercialize citrus fruit. These technologies should maintain the maximum physicochemical, sensory, and nutritional quality until the fruit reach the consumer. 
This thesis studies the effect of: (1) two innovative quarantine treatments, such as insecticidal atmospheres (IA) and low doses X-ray irradiation in combination with short periods of cold-quarantine storage on the nutritional quality of mandarins 'Clemenules', (2) the combination of IA applied at high temperatures with cold-quarantine storage in the physicochemical, sensory, and nutritional quality of 'Valencia' oranges, (3) the application of a chitosan edible coating at different solid content (SC) on the physicochemical, sensory, and nutritional quality 'Oronules' mandarins and 'Valencia' oranges and (4) the application of edible composite coatings based on hydroxypropyl methylcellulose (HPMC)-lipid with different SC and beeswax:shellac ratio on the physicochemical, sensory, and nutritional quality 'Oronules' mandarins and 'Valencia' oranges.
Cold-quarantine treatment  (1.5 ēC for 6, 9 and 12 days) combined with IA (95% CO2 at 20 or 25 ēC) or X-ray radiation (0, 30, 54 and 164 Gy) did not affect negatively the total antioxidant capacity and total ascorbic acid (TAA) content of the 'Clemenules' mandarins. However, the flavanone glycosides (FGs) and total phenolic content were slightly modified.
Combinations of cold quarantine (1 ēC for 8, 16 and 24 days) and IA at high temperatures (95% CO2 to 23, 28 or 33 ēC) did not affect negatively the quality of ‘Valencia’ orange. The exposure of oranges to the IA at 28 °C reduced the weight and firmness loss compared to control fruits. The ethanol content increased in fruit exposed to IA applied at 28 or 33 ēC, but sensory quality not adversely affected. Combination of IA and 8 or 16 days of cold storage did not affect the TAA content of oranges; however when cold quarantine period increased to 24 days, treated fruit had lower TAA content than control fruit.
Chitosan coating application with different SC (0.6, 1.2 or 1.8%) reduced gas exchange, modifying internal atmosphere of 'Oronules' mandarins and 'Valencia' oranges stored 4 and 16 weeks at 5 ēC plus 1 week at 20 ē C, respectively. Increasing the SC of the coating increased the ethanol content in juice. However, sensory quality was not affected. Similarly, the SC of coating did not affect of nutritional quality of 'Valencia' oranges and 'Oronules' mandarins 
The effectiveness of composites edible coatings based on HPMC-lipid controlling weight loss of 'Valencia' orange was limited; while in 'Oronules' mandarins the coating with the highest SC and shellac content was effective controlling weight loss. Although edible coatings were effective maintaining fruit firmness, no relationship was observed between SC and beeswax:shellac ratio with this quality parameter. On the other hand, increasing SC and shellac content affected internal atmosphere and increased the ethanol content of the fruit during storage. Sensory quality of 'Valencia' orange was not affected by coating application. However, HPMC-lipid coatings with 8% SC induced off-flavor in 'Oronules' mandarins. The nutritional quality of citrus fruit was not significantly affected by coating application.