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The present study titled “Utilization of pomegranate (Punica granatum L.) peel
as a natural food colourant” was carried out in the Department of Postharvest
Management,College of Agriculture,Vellayani during the period 2021-2023, with the
objective of standardizing food formulations using pomegranate peel as a natural
colourant.
The study was carried out as two experiments with anthocyanin pigment extracted
by acidified ethanolic maceration of dehydrated peels of pomegaranate (Punica
granatum L.) fruits which were collected as a byproduct from processing unit.
Three processed food products viz., lime squash, jackfruit jelly and ashgourd
candy, each of liquid, semisolid and solid nature were prepared with incorporation of
anthocyanin pigment at 1%, 2% and 3% concentration along with control in the first
part of the experiment and were subjected to evaluation of chemical, nutritional and
sensory quality parameters for selecting the most acceptable pigment concentration.
Lime squash with 2% anthocyanin pigment had highest antioxidant activity
(89.44%) and higher anthocyanin content (7.42 mg100g-1
) with highest mean scores
for appearance (7.86), colour (8.22) and overall acceptability (7.52); hence, 2% was
selected as the optimum concentration of anthocyanin pigment for incorporation in lime
squash.
Jackfruit jelly incorporated with 3% anthocyanin pigment had lowest
acidity(0.89%), highest anthocyanin content (5.52 mg100g-1
) and a comparatively
higher antioxidant activity (41.00%) with maximum mean score of appearance (8.30),
colour(8.70) and overall acceptability score (8.13) and hence 3% was selected as the
optimum concentration of anthocyanin pigment for incorporation in jelly.
The optimum concentration of anthocyanin pigment for candy preparation
was found to be 2%, as it had high antioxidant activity (59.09%), higher anthocyanin
(6.24 mg 100g-1
) and highest ascorbic acid content (65 mg 100g-1 ) as well as best
appearance (7.80), color (7.90), and overall acceptability (8.0) score among the colored
candies. Anthocyanin content and antioxidant activity were lowest for colourless candy
and pigment incorporation did not adversely affect the flavour, taste and texture, but
colour and appearance of candies with no pigment were highest. Computation of overall
acceptability also showed the superiority of colourless candy with highest overall
acceptability score (8.30). Among the coloured candies, candy with 2% pigment
recorded the highest overall acceptability of 8.00; hence 2% was selected as the
optimum concentration of anthocyanin pigment for incorporation in candy.
Incorporation of anthocyanin pigment resulted in production of products rich in
anthocyanin contents and antioxidant activity. As the concentration increased from 1-
3%, anthocyanin content was increased and antioxidant activity was same for all the
pigment incorporated products.
The three products were prepared by incorporating the respective optimum
concentration of anthocyanin and pigment stability in products was assessed by storing
the products in glass containers under ambient and low temperature condition for a
period of 3 months in the second part of the study.
Ascorbic acid, anthocyanin content and antioxidant activity were higher under
low temperature compared to ambient storage in all the three pigment incorporated
products. The quality parameters of all the products were affected by storage period. A
reduction of 11.02%, 6.32% and 3.53% anthocyanin content was recorded in lime
squash, jackfruit jelly and ashgourd candy respectively, indicating a reasonably higher
pigment stability during storage.
The present study could formulate three different antioxidant rich processed
products incorporated with natural anthocyanin from pomegranate peel, with
comparatively better pigment stability for a period of three months, proving the
potential of pomegranate peel as a natural colourant in processing industry.