Phenolic acids bilberry

For phenolic acids in bilberry juice, a reversed-phase HPLC method (16) using a linear-gradient elution of (a) 2% aqueous acetic acid and (b) acidified, aqueous acetonitrile on two Cl8 columns was able to separate the 12 phenolic acids and flavonoids (three flavonol glycosides and three flavonols) in ethyl acetate extract. Phenolics in blueberries were extracted, isolated, and... 

Table 6. Composition of phenolic acids found in natural humus beneath bilberry Vaccinium myrtillus) plants in clearings of Norway spruce (Picea abies) in eastern France. Data ifom Souto et al., 2000.

Bilberry consists of the dried ripe Ifuit of Vaccinium myrtillus, a dwarf shrub of the Ericaceae family. Dried bilberries contain 1-5% catechins, approximately 30% invert sugar, and small amounts of flavonol glycosides (e.g., astragalin, quercitrin, isoquercitrin, hyperoside), phenolic acids (e.g., caffeic and chlorogenic acids), and anthocyanins, particularly glycosides ofmalvidin, cyanidin, and delphinidin [30]. 

Most HPLC applications used for phenolic analysis simply allow the room temperature to determine the operating temperature of the column, but elevated temperatures of between 30°C and 40°C are often applied for phenolics and derivatives in apples (14), carrots (15), apple juice (6,13), bilberry juice (16), and for cis-trans isomers of caffeic and p-coumaric acids in wines (17). Generally, a change in temperature has only a minor effect on band spacing in reversed-phase HPLC and has essentially no effect in normal-phase separations. Thermostatic control of the column temperature is generally recommended to provide reproducible retention. 

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