###### Abstract  
Color, being one of the most important sensory characteristics, could be associated to the phenolic compound content and/or the antioxidant activity of fruits and vegetables. In this study, linear ordering was used to build quality rankings of red table grapes based on color parameters or phenolic compounds. First, the principle component analysis (PCA) was used to show the association between color of red grape skins (evaluated in CIE L*a*b* and L*C*h systems) and their individual phenolic compounds (investigated by the HPLC), total polyphenol content (TPC), total anthocyanins (ACNs), as well as the antioxidant activity (DPPH) of five table grape varieties. It could be observed that the lightness (L*) and hue angle (h) are the color coordinates strongly related to some phenolic compounds and ACN, whereas a* was related to DPPH and TPC. Five distinct clusters could be observed from PCA analysis with dark-colored grape varieties showing high levels of ACN (3.48-5.83 mg/g), low lightness (47.8-53.0), and high h values (353.7-359.8\"). L*, a*, and h color coordinates were used to build table grape ranking. The second ranking was built based on phenolic compound content. Results of the two rankings were correlated. High Tau Kendall correlation coefficient (0.51, \(p\) = 0.000) indicated that linear ordering analysis, based on the simple color measurements, could be a useful tool for rapid screening of the quality of grapes. This could be valuable information for producers and consumers of the fruit making decision on the market. m 2022 2022 14 June 2022 14 June 2022 16 June 2022 126 June 2022 14 June 2022 14 June 2022 16 June 2022 126 June 2022 1  
In grape berries phenolic acids (hydroxycinnamic and hydroxybenzoic acids), stilbenes (resveratrol), flavonoids (quercetin, kaempfer, and myricetin), flavanone and anthocyanins are the most important antioxidant active compounds. Most of them are in the skins (30%) and seeds (60%) of grapes, while only around 10% is in the pulp [5]. The composition of grapes strongly depends on the variety, maturity stage of grape berries, viticultural and environmental factors [5]. In red grape varieties, the main phenolic compounds are anthocyanins [6,7]. They account for 42-51% of total phenolics in red grape berries, followed by hydroxycinnamic acid derivatives (30-31%) and flavan-3-ols (8-19%) [7]. Others [8] reported that, apart from anthocyanins, the predominant polyphenols in red grape skins are flavonoids in the form of glycosides (130-200 mg/kg fresh weight), followed by flavan-3-ols (41-93 mg/kg) and hydroxycinnamic acid derivatives (12-19 mg/kg). For white grapes, the predominant polyphenols are flavan-3-ols (54-97 mg/kg), followed by flavonoids (25-98 mg/kg) and hydroxycinnamates (13-38 mg/kg), which constitute 32-59%, 27-49%, and 13-19% of total phenolic compounds, respectively [8]. As reported by [PERSON] et al. [7], pink and white grapes are rich in hydroxycinnamic acid derivatives (43-74%), followed by flavonoids for white cultivars (17-43%) or anthocyanins for pink colored cultivars (21%). Phenolic compounds are responsible not only for the antioxidant activity of the fruit but also play an important role in the sensory characteristics, such as taste and color [7]. Flavan-3-ols and their polymeric forms proanthicyanidins contribute to bitter and stringent taste of the berries [9]. Anthocyanins are responsible for the red, purple, and blues color of fruit. When making purchasing decisions, consumers have always been attracted by the color as a sign of a \"good\" quality product. In the case of fruit, the more vivid color the higher quality of the fruit is attributed [10]. Color, being one of the most important sensory characteristics, could be associated with the phenolic compound content and/or the antioxidant activity of fruit and vegetables [10,11]. Recently, many efforts have been made to obtain the grape varieties of high polyphenol content, which provides beneficial health effects for humans [4].