Blackcurrants
What are Antioxidants

Antioxidants have received a lot of press for their possible role in preventing the degenerative diseases of aging (e.g. cancer and heart disease).

This is because antioxidants help protect against the harmful effects of free radicals and other highly reactive chemicals, which may cause cell damage.

Free radicals are generated in our body all the time as a by-product of breathing oxygen, exercising and breaking down food for energy as well as through environmental factors such as UV exposure from sunlight, smoking, pollution and certain chemicals.

Free radicals have been implicated in the universal degenerative diseases of aging such as cancer, heart disease and cataracts, and also diseases with more specific causes such as Parkinson's disease and pancreatitis.

There are several different types of antioxidants found in many fruits, vegetables, grains and beverages. The phenolics include some important antioxidant compounds, such as the flavonoids that are present in most fruit and vegetables as well as tea and red wine. As well as antioxidant effects, some flavonoids may have other positive effects such as stimulating the immune system.

A second major class of antioxidant compounds are the carotenoids, yellow, orange and red pigments found widely in nature. Common carotenoids include beta-carotene and lycopene (the red compounds present in tomatoes). Carotenoids vary in their antioxidant activity, e.g. lycopene has much stronger activity than B-carotene.

Vitamins C and E also have antioxidant activity. Vitamin C is an essential water-soluble vitamin, not manufactured in the human body, with antioxidant and immune stimulating properties. Cigarette smoking and high alcohol intake can deplete levels of Vitamin C in the body.

Some micronutrients, such as selenium, zinc and cah also assist in controlling free radicals and repairing injury to the cell.

What anthocyanins are in blackcurrants

Research analysis has shown Blackcurrants to have the following complement of antioxidants:

Antioxidant

Content per 100 g fresh

Vitamin C 221 mg
Vitamin E 1.4 mg
Carotenoids
(beta-carotene equivlents)
160 mg
Phenolics 2,160 mg

- Anthocyanins

1,200 mg


The Individual Anthocyanins in Just the Berries Blackcurrants

cyanidan-3-rutinoside 42%
delphinidin-3-rutinoside 41%
cyandin-3-glucoside 11%
delphinidin-3-glucoside 6%

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.

Berryfruit in a context of fruits and vegetables

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.

Refer Dr Carolyn Lister at
Crop and Food Research
www.crop.cri.nz