# Late Shelf Life Saturation of Golden Delicious Apple Parameters: TSS, Weight, and Colorimetry
## 1 Introduction
Compared to RGB imaging, the hyperspectral approach showed more promise for objectively differentiating apple ripeness during shelf life. The fruit's surface chlorophyll degradation occurs throughout the ripening phase; while-colored pigments, such as carotenoids (yellow) and anthocyanins (red), are created. Two colors may appear: one is the background color, yellow, and the other is the surface color, red. Golden Delicious apples have a faint pinkish tint ranging from green to yellow-green tones [24]. Some cultivars, such as Golden Delicious, have a long shelf life of roughly four weeks at room temperature [25], although the fruit softens and the peel color changes from green to yellow [26]. Analysis of the green-to-yellow skin color shift in Golden Delicious apples revealed that carotenoid production and chlorophyll degradation are responsible for the alterations [27; 28]. [PERSON] et al. [29] proposed a non-destructive determination of the Golden Delicious ripening stage. However, they confirmed in the end that their development is still a destructive estimation due to their chlorophyll content assay of the apple peel. Even though numerous research has been conducted during storage, there is little information about fruit color changes and the classification of ripening stages during shelf life. [PERSON] et al. [26] showed that color changes during storage could be used as a classification approach. Apple quality deteriorates significantly during storage, impacting consumer acceptance [30; 31]. According to the findings in the literature above, our approach focuses on highlighting the post-harvest late shelf life saturation of Golden Delicious color parameters, based on weight, TSS, and colorimetry data, which is raised as a novel approach in the field. Due to its resemblance to the human perception of color, CIELAB color space is an appropriate choice to describe the color ingredients of fruits and vegetables [5; 32]. The CIELAB color scale comprises L*, a*, and b* coordinates, with L* denoting brightness, a* denoting red or green, and b* denoting yellow or blue color perception. Complex computer vision systems require sensor-based measurements, but flexible and frequent in-situ investigations are a continuous requirement during ambient storage. A calibrated portable device (in a laboratory environment at this research stage) can also be implemented to examine the color changes of different ripening stages, taking multiple, simple, and fast measurements on the surface of given fruits. Besides examining fresh products, it is also essential to evaluate the results mentioned in the last stage of ripening, where the limiting parameters of shelf life can be observed with the saturation limits of the investigated changes in the crucial color parameters. In the case of room temperature storage, these circumstances can be achieved if the examined fruits are selected from the end of the season. This study aims to characterize the ripening process with an applied sensor-based colorimetric approach. It aims to identify the changes in the weight, color, and TSS properties of Golden Delicious apple fruit during storage at room temperature, focusing on the changes in TSS and color parameters that objectively indicate the shelf life limitations of the given cultivar based on asymptotic regression. For the description of the observed limits of the parameters, the approach of exponential asymptotic regression was considered instead of power function [25] to characterize the weekly ripening process, and a color sensor-based measurement method was applied to improve the effectivity of such investigations further.