A beverage product that includes water, a color derived from natural sources, and a compound in an effective amount to inhibit fading of the color derived from natural sources. The compound is an unsaturated acid, and may be selected from the group consisting of maleic acid, maleic anhydride, aconitic acid, mesaconic acid, itaconic acid, and/or fumaric acid. The incorporation of the compound can be particularly useful for inhibiting color fading of the beverage product under thermal stress. The colors derived from natural sources may be an anthocyanin, cyclohexene dione dimers and/or a color derived from the reaction of an iridoid and amino acids. For example, the colors may include purple sweet potato, black carrot, purple carrot, black currant, blueberry, carthamus yellow, and/or gardenia blue. The compound can be effective to prevent color fading even in the presence of ascorbic acid, which promotes the fading of colors derived from natural sources.