Effects of postharvest arginine, citrulline and ferulic acid applications on some physiological events in fresh-cut kiwi and mandarin fruits

This master's thesis evaluates the effects of applications of ferulic acid, citrulline, and arginine on the fresh-cut forms of two different fruit types, namely Satsuma mandarin (Citrus unshiu) and Hayward kiwi (Actinidia deliciosa). After the applications were carried out, the fruits were stored at 4 °C for six days. Analyses were conducted every two days to monitor changes in quality parameters during the storage period. The applications on Satsuma mandarin effectively preserved the quality by reducing the weight loss to a minimal level of 0.17%, while keeping the pH and total soluble solids (TSS) levels stable. However, the citrulline application significantly decreased the total phenolic content. The effects of these applications on antioxidant properties and color stability remained limited, indicating a need for further optimization in the future. Similar applications conducted on Hayward kiwi demonstrated that the combination of ferulic acid, arginine, and citrulline reduced fruit water loss by 0.83±0.09%, with the highest weight loss recorded at 1.40±0.33% for the ferulic application. Depending on storage duration, pH values ranged from 3.83 to 3.93, and total soluble solids values varied between 12.17 and 12.58. Additionally, it was concluded that the formulations applied to this fruit significantly contributed to preserving the nutritional value and quality, with an optimum consumption period limited to 48 hours. In conclusion, this study shows that the applications of ferulic acid, arginine, and citrulline are effective in enhancing the quality of both Satsuma mandarin and Hayward kiwi fruits, and that biochemical applications have great potential for developing fresh fruit preservation strategies. Future research may provide an important foundation for the discovery of effective components and strategies.