Articles
THE CHEMICAL COMPOSITION OF SOME VACCINIUM CORYMBOSUM VARIETIES
Some years ago, however, they were taken as a raw material from which anthocyanosides were extracted and used in therapeutics.
In 1975, 1 400 tons of Vaccinium myrtillus berries were required to get these anthocyanosides used for medicinal purposes.
Because of the increasing demand of Vaccinium myrtillus berries, it was important to see whether berries of other Vaccinium species had the same chemical composition and could be used for the anthocyanoside extractions.
It was, however, impossible to plant a Vaccinium myrtillus culture because this species requires partial shade, preferable that of conifers.
This culture would have had to have been preceded by the planting of such trees and at best, it would have taken 15 years to get the required shade.
Preliminary analysis showed that the content of anthocyanosides, in the species cultivated most, was very limited.
On account of these results, we chose the corymbosum species, variety Amblue, which grows easily in the Massif Central, particularly in granite grounds near Clermont-Ferrand.
Plantings were done in such areas at an altitude of 540 metres.
The pH was 5. Some acid fertilizer and oak or chestnut chips were added.
These chips are antiseptic and hinder bacterial development.
Some plants were cut slightly.
This operation is, however, undesirable because it decreases the fructifying during the first years.
The planting was followed by only one watering.
The plants were between 0.6 and 0.8 metres high.
The flowering spread over a period of more than 2 months, mainly from the end of February to the end of April.
Fruit maturation began near the end of July and went on up the beginning of October.
Harvesting was best from August – September.
The maturation time changed with exposure.
It was interesting to compare the anthocyanoside content of the fruit at the beginning to that at the end of summer.
For 5 years, samples were taken several times throughout the maturation period.
The anthocyanoside content of each was determined.
It seemed from the start that no anthocyanoside was present in the colourless pulp of Vaccinium corymbosum.
In fact, the analysis showed that it contained leucoanthocyanosides, which were transformed into anthocyanosides while being extracted.
The separation of the anthocyanosides is done by means of fermentation, which has been summarized as follows: Saccharomyces, previously acclimatized yeasts, are used to ferment the pressed berries.
After the fermentation occurs, the juice is filtered and the anthocyanosides are separated by christallization.
During fermentation, the leucoanthocyanosides are transformed quantitatively into anthocyanosides, thereby increasing the yield.
Most of the anthocyanosides are, nevertheless, contained in the pericarp of the fruits.
In order to determine the maturation level of the berries, some of them are pressed and the optical density of the juice is measured with a spectrophotometer.
Berries harvested at the same