Beetroot has long been identified as a raw material source for the extraction of naturally occurring colour pigments, providing vibrant red to violet tones that can be further refined into yellow/orange and blue/purple pigments.
Research to isolate a beetroot variety with high colour pigment, in correlation with soil conditions and planting windows.
Beetroot variety isolation in relation to colour pigmentation were designed to determine the impact of variety, soil type and seasonality on the resulting colour pigment of beetroot juice.
Colour pigmentation versus beetroot variety was achieved by selecting three high pigment beetroot varieties from the preliminary 2006 investigations.
Beetroot varieties identified as ‘BT5004’, ‘Deep Detroit Red’ (DDR) and ‘Pablo’ were then:
1. Planted in two soil types. Heavy Black Cracking Clay and Light Clay Loam
2. Planted during two planting windows. Early and Mid Beetroot Season.
Research of beetroot variety isolation in relation to colour pigmentation was aimed to identify:
1. Which cultivated beetroot variety yielded higher colour pigmentation
2. The impact of planting and harvesting windows on colour pigmentation
3. The impact of soil conditions on colour pigmentation
Frank Van Doore
- The increasing demand and consumer focus to replace synthetic food colouring with natural derivatives within the food industry has driven industry to source colour pigments from fruits and vegetables.
- Colour pigments within beetroot, known as betalains have been well researched. Betalaines are divided into two colour shades, betacyanin and betaxyanthin.
- cv.‘Pablo’ yielded the highest betanin content
- Soil type marginally affected betanin recovery
- The impact of seasonality was inconclusive
Variety and Seasonality
Beetroot can be isolated by variety to yield higher colour pigmentation in raw extracted beetroot juice.
‘Pablo’ with an average diameter of 78mm grown in light clay loam, within the mid season planting window, produced highest betanin content in raw extracted juice.
However this variety did not consistently perform highest across all trial plantings.
‘Deep Detroit Red’ produced consistent results across trial plantings, with the exception of mid season – heavy black cracking clay.
Furthermore results indicate that this particular variety has higher levels of betaxyanthin pigments.
‘Deep Detroit Red’ is not recommended as a raw material source for the production of beetroot concentrate when producing for blue/purple shading, due to levels of yellow/orange pigmentation.
However this variety could be utilised for the production of yellow/orange shaded concentrates.
‘BT5004’ preformed the lowest and is not recommended for future colour development work.
Seasonality marginally affected total betanin recovery when both trial plot data is compared.
Light clay loam consistently produced beetroot with lower soluble solids and higher betanin content.
in contrast, heavy black cracking clay produced beetroot with higher soluble solids and lower betanin content.
Therefore selection of a beetroot yielding lower soluble solids grown in light clay loam will provide a higher betanin beetroot concentrate
All beetroot varieties in relation to betanin recovery preformed the lowest during Trial Plot B – mid season, grown in heavy black cracking clay.
This project was funded by Horticulture Australia Ltd through the National Vegetable R&D Levy and by voluntary contributions from Golden Circle Limited.
The Australian Government provides matched funding for all HAL’s R&D activities.