Natural food and beverage colourings - Natural Food Additives, Ingredients and Flavourings - page 27

extractor/natural colour supplier is to take these factors into account to provide a
consistent fi nal product for use as a food colour.
To comply with European legislation the strain Beta vulgaris L. var. rubra must
be used. 3 The red pigment in beetroot juice is called betanin and this typically
makes up 80% of the total pigments present. There is another pigment present
called vulgaxanthin, which is yellow. Consistent shade is obtained and specifi ed
to the fi nal user against a ratio of betanin and vulgaxanthin. Beetroot juice also has
a low level of anthocyanins present due to the carryover from pigmentation of the
vegetable's skin, but this is insignifi cant colour compared with the impact of
the betanin.
Beetroot juice is obtained in processes similar to fruit juice extraction with
either pressing or diffusion. The juice obtained from this is fi ltered, centrifuged,
Pasteurised and concentrated by a combination of vacuum and ultrafi ltration. The
standard commercial product is typically 0.5% betanin and contains approximately
70% solids. The juice can also be spray-dried onto a carrier to provide a powder
for applications and processes more suitable for powder based colours. Such
powder beetroot colours typically contain 0.3% betanin.
Beetroot juice disperses readily to give a clear red colour with some blue notes
when in clear application. In milk-based applications the colour is a classic pink
colour that is associated with strawberry fl avoured products. The typical dose for
ice cream is up to 0.5% of a beetroot juice extract to account for the overrun
applied. This is a relatively high dosage for a natural colour, but even at this dose,
there is no taste carryover experienced.
The shade of beetroot juice in application is independent of pH within the
range typically experienced in food and beverages but at high pH (7.5 and above),
betanin can degrade by hydrolysis into a yellow/brown colour.
Beetroot juice has fair stability to light but insuffi cient to support its use in a
red beverage in clear packaging. Some suppliers of beetroot juice add ascorbic
acid as an anti-oxidant to increase both general and specifi c heat stability but the
evidence behind this seems inconclusive.
The main issue with beetroot juice is its sensitivity to heat processing. The
colour degradation varies depending on application and specifi cally factors such
as the temperature applied, duration of heating and water activity of the product.
With foods coloured with beetroot it is often not how high the temperature goes
but how long heat is applied. Beetroot juice can survive HTST (high temperature
short time) processing as long as there is a cooling stage applied. Pasteurisation is
more challenging but there are reports 4 of the beetroot colour surviving in products
with low water activity. More extreme processes such as retorting and extrusion
do not to allow the survival of beetroot as a colour.
Traditional applications for bulk use of beetroot liquid as a food colour are ice
cream, milk drinks, dairy products, sorbets, icings and decorations, and yoghurts.
These applications have processing and supply chain conditions that suit the heat
instability of beetroot. For example once the liquid ingredients are mixed in ice
cream and freezing is applied to create the product, the temperature remains low
for the rest of the life of the ice cream.

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