Use of natural extracts as color preservatives in drying apple fruits

This study aims to examine how color parameters (L*, a*, b*, Chroma, Alpha, Delta E, BI) change in drying processes carried out with different drying temperatures and pre-treatment applications. The effect of drying temperatures and pre-treatment applications on visual quality, especially color tone and brightness, was investigated. In the study, drying of apple slices was carried out using different pre-treatment methods such as normal drying, Dia Natura Base, and Sorrel extract, and different temperatures such as 50 °C, 55 °C, 60 °C, 65 °C, 70 °C. Color parameters were measured using Adobe Photoshop's Image Analysis Tool, and the effect of each temperature and pre-treatment combination on color saturation, yellowness, red-green tones, yellow-blue tones, and brightness was examined. In addition, parameters such as Delta E (color change) and BI (browning index) were calculated, and the relationship between color changes and browning rates with temperature and pre-treatment applications was evaluated. The lowest ΔE values were obtained with pre-treatment with Sorrel Extract (10 → 20). Even at 70 °C, the ΔE = 20 value was maintained. This shows that sorrel extract, which has a high antioxidant content, prevents oxidative color changes by *protecting phenolic compounds*.