Het vitamine C gehalte van zwarte bessen is het hoogst van al onze inheemse vruchten. Met een gemiddelde van 181 mg per 100 g verse bessen ligt dit extreem hoog en is volgens de Amerikaanse aanbevelingen voor volwassenen zelfs 3 maal zoveel als de aanbevolen dagelijkse hoeveelheid (ADH). Vergelijk hierbij appelsienen die met 50 mg per 100g vier maal lager scoren.                 Daarnaast zijn er nog veel secundaire inhoudsstoffen die door voedingswetenschappers als voorbehoedend voor hart – en bloedsomloopstoornissen en kanker erkend worden. Dit zijn de anthocyanen die de pel zwart en het sap zwartrood kleuren. Daarbij zijn de bessen nog rijkelijk voorzien van ballaststoffen en kalium, daarbij ook calcium en ijzer.

Het gehalte aan antioxidanten is wellicht de voornaamste factor voor het bepalen van de gezondheidswaarde. Ze maken de gevaarlijke radicalen onschadelijk.

Ik  voeg hieronder een tekst in van het Scottish Crop Research Institute

Fruit quality and nutritional aspects

The main fruit quality objectives in blackcurrant breeding have traditionally focused on ascorbic acid (AsA) content. The range of AsA in commercially available varieties varies from 130 - 200 mg/100 ml juice, but this increases to over 350 mg/100 in some breeding lines and even higher in wild accessions of R. nigrum var. sibiricum. Some reports suggest that the AsA contained in blackcurrant fruit is more stable than most other sources, possibly due to the protective effects of anthocyanins and other flavonoids within the berries. The main period of AsA accumulation coincides with the berry expansion phase, soon after fertilization, and genotypic rankings of AsA content established in this early stage remained constant thereafter (Viola et al 2000).

Blackcurrants and other Ribes species are outstanding sources of antioxidants, both in the form of high ascorbate levels but also in the high concentrations of polyphenolic compounds that are contained within the fruit. The latter include flavonoids, such as anthocyanins and flavonols. The amounts of these compounds present in the berries varies with cultivar, environment and agronomic practices. The main anthocyanins in blackcurrant are cyanidin-3-rutinoside, delphinidin-3-rutinoside, delphinidin-3-glucoside and cyanidin-3-glucoside, and the relative proportions vary between genotypes. For example, a survey of available germplasm has shown that western European varieties contain more cyanidin derivatives, whilst Scandinavian varieties contain a higher proportion of delphinidin derivatives. Since the latter are generally more stable, many breeding programmes including the SCRI programme have preferentially selected for a high delphinidin:cyanidin ratio (Brennan 1996) and varieties such as 'Ben Alder' are particularly high in delphinidins. There are also within blackcurrant fruit minor compounds, such as cyanidin-3-sophoroside, delphinidin-3-sophoroside and pelargonidin-3-rutinoside, which collectively amount to ca. 5% of the total anthocyanins.

The stability of these nutritionally important compounds in blackcurrant during processing has been assessed, and whilst juice processing can cause considerable losses of ascorbate, the phenolic compounds are relatively stable during processing and antioxidant activity is retained in the juice. However, there may potentially be changes caused within the phenolic compounds by the processing, which may affect bioavailability. There are at present various studies worldwide, involving clinical trials, to ascertain how much of the ingested blackcurrant phenolics are actually taken up by the body and thereby play a role in proposed health benefits from berry consumption.

Tabel 1  Gemiddelde Voedingswaarde per 100 g verse bes

(Gegevens: United States Departement of Agriculture: Nuttrient Database)