A process is provided for obtaining a tannin extract isolated from grapes using grape seeds. The process comprises: preparing the grape seeds as the source of tannins； preparing an aqueous solution of a polyphenol-solubilising agent selected from urea, a compound containing the SO3 group and sodium hydroxide at concentration ranging between 1% and 15% by weight； performing a single extraction in an autoclave reactor； separation and direct concentration in order to produce the isolated extract. The invention also relates to the tannin extract obtained. The new tannin extract isolated from grape seeds comprises a mixture of tannins and non-tannins, the composition whereof provides the extract with improved antioxidant and light fastness properties. The tannin extract isolated from grape seeds further comprises a colouring agent.
