Anthocyanins are compounds naturally found in berries such as blackcurrants. They possess high levels of antioxidant activity and are also responsible for the dark purple colouring of blackcurrants. Close to 300 different anthocyanins have been discovered to date. They are found amongst many different types of berries.
Anthocyanins inhibit the enzymes Cyclo-oxygenase 1 and 2 and appear to reduce inflammation and reduce the effects of arthritis in the body.
There are many factors that affect the stability of anthocyanins. It has been found that the heat and light sensitive pigments can easily be destroyed during processing of fruit and vegetables. Processing of blackcurrants is very carefully controlled to prevent degradation during processing.
Types of Anthocyanins in Blackcurrants
A study was conducted to detect anthocyanins from blackcurrants in human urine . Urinary samples from 4 health volunteers were collected over a period of 5 hours with intervals of 30 minutes after the ingestion of 200 ml blackcurrant juice.
Their results showed that the urine contained two types of Delphinidins and two types of Cyanidins. Results demonstrated that the levels of the 4 main anthocyanins in the urine were low, at 0.020-0.050%, and it was thus concluded that most of the anthocyanins were absorbed.
The Individual Anthocyanins in Just the Berries Blackcurrants
Many of the antioxidant characteristics associated with berries can be attributed to the anthocyanin content. Anthocyanins are the deep pigments that give berries their rich dark colours. Four anthocyanins: delphinidin-3-rutinoside, cyanidin-3-rutinoside, delphinidin-3-glucoside and cyanidin-3-glucoside make up 98% of blackcurrant anthocyanins, the remaining 2% comprise 11 other anthocyanins including petunidin and malvinidin glycosides. Other polyphenols in blackcurrant are quercetin, myricetin, kaempferol, gallic acid, hydroxycinnamic acid and p-coumaric acid.
Analysis of a wide range of fruits and vegetables carried out by Prior et al of Tufts University, indicated that common berryfruits grown in the USA were high in antioxidant activity as measured by "Oxygen Radical Absorbance Capacity" (ORAC)
Figures drawn from a table of ORACs presented in "Agricultural Research, February 1999, p 16" illustrate the very high antioxidant activity of berryfruit in relation to other fruits and vegetables.
The results highlighted Blueberry in particular as being high in antioxidant activity.
Comparative tests carried out by the Crop and Food Research Laboratories in New Zealand indicated that New Zealand Blackcurrant fruit was up to 3 times higher in antioxidant activity than Blueberry.
The average results obtained in comparative tests on extracts 3 samples of New Zealand Blackcurrants compared with those on extracts from Blueberry were as follows:-
|Antioxidant activity* mmol TEAC/g fruit weight||189||78|
|Anthocyanin HPLC mg/g fruit weight (Based on peak area relative to cyanidin-3-glucoside
|Total Phenolics mg gallic acid equivalent/g fruit weight
Calculated using Folin Ciocalteu reagent
TEAC = Trolox Equivalent Antioxidant Activity measured by ABTS test method (Ref Miller, Rice-Evans).