Biochemical and Mineral Profiling of ‘Karaevrek’ Grape from the Perspective of Sustainability and Waste Management

Abstract

Recent increases in population density, environmental pollution, and global warming necessitate more efficient use of food resources. Research into the utilisation and economic recovery of waste materials from food processing has gained momentum. This study investigates the health benefits of the ‘Karaevrek’ grape variety, cultivated in the Kayseri/Incesu region, by examining its antioxidant capacity, phenolic and flavonoid content, and mineral and bioactive compound profiles in the fruit flesh, grapeseeds, leaves, and pedicels. Notably, grapeseeds exhibited the highest total phenolic content (176.11 ± 3.15 mg gallic acid equivalents/g) and strongest antioxidant activity (95.20 ± 0.21% radical scavenging; 352.00 μg trolox equivalents/mL Copper (II) Reducing Capacity), alongside the highest concentrations of all analysed minerals, particularly potassium (296.81 ppm), magnesium (122.22 ppm), and iron (8.96 ppm). Leaves (KL) displayed the highest flavonoid content (301.98 ± 6.44 mg quercetin equivalents/g), indicating complementary bioactive potential. Phosphorus was most abundant in the stem (2.73 ppm), while magnesium was prominent in fruit flesh (13.36 ppm). Gas Chromatography/Mass Spectrometry (GC-MS) analyses identified 54 compounds, including antioxidant hexadecanoic acid methyl ester and cardioprotective Vitamin E. The findings suggest that ‘Karaevrek’ grapes, particularly their grapeseeds, leaves, and pedicels, could be valuable natural additives in the food industry, emphasising the need for further studies on local varieties’ biochemical properties.