HPLC analysis of carotenoids in four varieties of Calendula officinalis L. flowers

Calendula officinalis L. is a medicinal plant that accumulates large amounts of carotenoids in its inflorescences. The yellow-to-orange colour of inflorescences is mostly due to carotenoids and the shade is dependent on pigments content and profile.We investigated the carotenoid content and profile in four selected varieties of Calendula: Double Esterel Orange, Radio Extra Selected, Bonbon Abricot and Double Esterel Jaune. The total carotenoid content was evaluated spectrophotometrically and pigments were separated using chromato-graphic methods (CC, TLC, HPLC). An HPLC gradient system with a Nucleosil C18 column and a Waters PDA detector was used for separation and identification of carotenoids. The carotenoid content was higher in orange varieties: 276 mg/100 g fresh flowers for Double Esterel Orange and 111 mg/100 g fresh flowers for Radio variety. All varieties contain the same pigments but there are significant differences for the ratio between individual pigments. Orange varieties contain higher amounts of hydrocarbons: 44.5% of total carotenoid in Double Esterel Orange; while yellow varieties contain mostly oxygenated derivatives: 97% of total carotenoids in Double Esterel Jaune. The main pigments identified were: flavoxanthin, lutein, rubixanthin, b-carotene, b-carotene and lycopene. The cultivation of orange varieties is recommended especially when the pharmacological products for skin protection are envisaged

Xanthophyll Esters in Fruits and Vegetables

Carotenoids possessing hydroxyl groups (xanthophylls) are often found as fatty acid esters in many fruits and vegetables. The developments in high resolution chromatographic and spectroscopic techniques have led to a detailed characterization of xanthophyll esters in commonly consumed fruits and vegetables, such as apples, apricots, mandarins, mangoes, papayas, red and chili peppers, potatoes or squash. Some more rich sources have been identified, like wolfberry (goji), sea buckthorn, persimmon, whose popularity is increasing due to the high content of bioactive compounds. Esterification increases the lipophilicity of xanthophylls and contributes to the sequestration of carotenoids, to the formation of specialized structures in the chromoplasts and to an increased photoprotection. The process occurs during ripening in fruits and it is associated with a significant change in colour. Even if the specific enzymes which catalyze the esterification process were not characterized yet in fruits, detailed analytical data regarding the carotenoid composition suggested a selectivity of these enzymes for certain fatty acids and selectivity for the ring in the case of non-symmetric xantophylls. Xanthophyll esters seem to be efficiently hydrolyzed and absorbed in humans leading to a comparable bioavailability to the unesterified compounds. In addition, the xanthophyll esters preserve the antioxidant capacity of the parent compounds while having a better stability in fruits during storage and processing. All these properties are important from the perspective of the use of fruits rich in xanthophyll esters as valuable components of the human diet and as sources of bioactive compounds in the prevention of severe degenerative diseases

Comparative Study of the Antioxidants Compounds in Fresh and Thermally Processed Tomatoes Juice

The purpose of our study was to determine the influences of thermal processing of tomato juice, in a manner similar to that commonly used in traditional cuisine, on the concentration of antioxidant compounds: total carotenoid and their profile; concentration of lycopene; concentration of ascorbic acid and total polyphenols. The boiling of tomato juice resulted in a significant increase in the concentration of total carotenoids and lycopene. No statistically significant differences in total carotenoids and lycopene content occurred depending on the boiling time. In fresh juice, ascorbic acid had average values of 20.73 mg /100g and significant decreased depending on the boiling time. Processing of tomato juice by boiling for 15 minutes or 30 minutes causes a slight increase in the concentration of phenols. The results obtained in this study have shown that, in the case of tomato juice, cooking by boiling determines the decrease of ascorbic acid concentration, but on the other hand makes the carotenoids and phenolic compounds more available, thus being nutritionally beneficial