Bioactive Compounds and Antioxidant Capacity of Rosa rugosa Depending on Degree of Ripeness.

Maturity stage affects the bioactive compounds as well as the antioxidant capacity in the fruit. This study was designed to identify and quantify carotenoids, as well as to evaluate vitamin E, vitamin C, antioxidant capacity and total phenolic compounds of Rosa rugosa hips at different degrees of ripeness. HPLC (high performance liquid chromatography) analysis showed different types of carotenoids at different stages of maturity of R. rugosa hips with significant differences (p ˂ 0.05), where the maximum concentration was observed at late harvesting. In the hips investigated, only α-tocopherol was detected, the maximum concentration of both vitamin E and vitamin C was obtained in the orange hips with significant difference (p ˂ 0.05). On the other hand, the highest hydrophilic and lipophilic TEAC (Trolox equivalent antioxidant capacity) values, as well as total phenolic contents, were determined in the mature hips (red colour) with significant difference (p < 0.0001) and (p < 0.001) respectively, whereas ORAC (oxygen radical absorbance capacity) showed lower activity in the mature hips with significant difference (p ˂ 0.05). Late harvesting is recommended if a high content of carotenoids is desired, while harvesting should be carried out earlier if a higher vitamin E and vitamin C content is desired, which in turn affects the antioxidants capacity.

In Vitro Bioaccessibility of Carotenoids and Vitamin E in Rosehip Products and Tomato Paste As Affected by Pectin Contents and Food Processing.

Limited bioavailability of antioxidants present in food from fruits and vegetables matrices is determined by their low bioaccessibility due to the physical and chemical interactions of the antioxidants with the indigestible polysaccharides of cell walls. Therefore, this in vitro investigation aimed to assess the bioaccessibility of carotenoids and vitamin E from rosehips as well as from tomato paste and to investigate several aspects of effects of pectin contents and food processing on bioaccessibility. Following the addition of the enzyme mixture Fructozym P6-XL, the bioaccessibility of carotenoids from rosehips as well as from tomato paste significantly increased. The average relative increase in bioaccessibility from rosehips was lower for ( all-E)-ß-carotene compared with ( all-E)-lycopene and ( all-E)-rubixanthin. In contrast, increases of bioaccessibility of α-tocopherol were comparable for rosehip samples and tomato paste.

Characterization of carotenoids and vitamin E in R. rugosa and R. canina: Comparative analysis.

The hips of Rosa species have gained more attention in recent years due to their high contents of antioxidant compounds. This study was designed to compare rosehips of the two roses species Rosa rugosa and Rosa canina, including different products, on carotenoid contents, including phytoene and phytofluene, as well as vitamin E. The investigation allowed the identification and quantification of types of (Z)-isomers of lycopene and rubixanthin in both rosehips and focused also on isomerisation of both carotenoids. The carotenoid identification and quantification were done using HPLC-DAD and LC-MS/MS. The statistical analysis revealed significant differences (P<0.05) in carotenoid contents and (P<0.001) in vitamin E contents between different rosehips species. The HPLC analysis showed that carotenoid contents varied between rosehips species. The isomerisation of (all-E)-rubixanthin and (all-E)-lycopene using iodine-catalysed photoisomerisation showed that the (5'Z)-isomer gazaniaxanthin is the main (Z)-isomer of rubixanthin and the (13Z)-isomer is the main (Z)-isomer of lycopene.