4.4. Analysis of Total Phenolic and Flavonoid Contents

The frozen tomato fruit samples were ground into fine powder using liquid nitrogen. Total phenolic and flavonoid contents were extracted and assayed according to the method depicted by Toor and Savage [59] with some modifications. The frozen powder sample (about 1 g) was homogenized in 6 mL of cold ethanol (40%, v/v). After being extracted in a water bath at 60 °C for 1 h, the homogenate was centrifuged at 4 °C with 9000× g for 15 min. The supernatant was used for the analysis of total phenolic and flavonoid contents. Total phenolic content was measured with the Folin–Ciocalteu reagent and 7.5% (m/v) Na₂CO₃ and expressed as gallic acid equivalents based on fresh weight, in mg 100 g⁻¹. Total flavonoid content was determined with a NaNO₂-Al(NO₃)₃-NaOH reagent and expressed as rutin equivalents based on fresh weight, in mg 100 g⁻¹.