Cooked prawn colour is known to be a driver ofmarket price and a visual indicator of product quality for the consumer.
Although there is a general understanding that colour variation exists in farmed prawns, there has been
no attempt to quantify this variation or identify where this variation is most prevalent. The objectives of this
study were threefold: firstly to compare three different quantitative methods to measure prawn colour or pigmentation,
two different colorimeters and colour quantification from digital images. Secondly, to quantify the
amount of pigmentation variation that exists in farmed prawns within ponds, across ponds and across farms.
Lastly, to assess the effects of ice storage or freeze-thawing of raw product prior to cooking. Each method was
able to detect quantitative differences in prawn colour, although conversion of image based quantification of
prawn colour from RGB to Lab was unreliable. Considerable colour variation was observed between prawns
from different ponds and different farms, and this variation potentially affects product value. Different postharvest
methods prior to cooking were also shown to have a profound detrimental effect on prawn colour.
Both long periods of ice storage and freeze thawing of raw product were detrimental to prawn colour. However,
ice storage immediately after cooking was shown to be beneficial to prawn colour. Results demonstrated that
darker prawn colour was preserved by holding harvested prawns alive in chilled seawater, limiting the time between
harvesting and cooking, and avoiding long periods of ice storage or freeze thawing of uncooked product.