Determination of Carotenoids in Fruits of Rosa sp. (Rosa Canina and Rosa Rugosa) and of Chokeberry (Aronia Melanocarpa)

Carotenoid composition of fruits of two Rosa species (Rosa canina and Rosa rugosa) and of chokeberry (Aronia melanocarpa) was studied by high performance liquid chromatography. Nine carotenoids were determined: three carotenes (lycopene, ζ-carotene, β-carotene) and six xanthophylls (neoxanthin, trans-violaxanthin, cis-violaxan-thin, 5,6-epoxylutein, lutein, β-cryptoxanthin). This high number of compounds classified these fruits among those with the greatest variety of carotenoid pigments. Quantitatively large differences occurred in the carotenoid composition of the three fruits. Rosa hips contained the highest concentrations of total carotenoids, which were mainly comprised of lycopene and βcarotene. Conversely, total xanthophylls were low. In contrast to Rosa, fruits of Aronia were lower in total carotenoids while xanthophylls composed a higher proportion.     

Changes in Grape Seed Phenols as Affected By Enzymic and Chemical Oxidation in vitro

An in vitro oxidation system containing all the phenolic compounds of an extract of grape seeds and phenol oxidases (catechol oxidase from grapes and laccase from grey mold of grape Botrytis cinerea) was used to determine the effects of enzymic oxidation on seven phenolic compounds: gallic acid, (+)-catechin; (-)-epicatechin and four procyanidins, dimers of (+)-catechin and (-)-epicatechin units. HPLC determinations showed that there was considerable depletion of phenolic compounds in the extract by both enzymes since the quantities of all the compounds fell during enzymic oxidation. When a pure chemical oxidation was compared, the decrease was very much slower.     

Anthocyanins in Fruits of Aronia Melanocarpa (Chokeberry)

Anthocyanins from fruits of Aronia melunocap (chokeberry) were extracted with acidified ethanol and methanol and fractionated by high performance liquid chromatography. The pigment composition was very simple as there were only four compounds. Semi-preparative HPLC, thin-layer chromatography and spectral techniques indicated cyanidin as a single aglycone and glucose, galactose, arabinose, and xylose as associated sugars. The relative proportions of anthocyanins were determined. The major components were cyanidin 3-galactoside and cyanidin 3-arabinoside.