MSc

The present study entitled “Standardization of anthocyanin extraction from
pomegranate (Punica granatum L.) peel” was carried out in the Department of Postharvest
Management, College of Agriculture, Vellayani during the period 2020-2022, with the
objective to standardize process parameters for anthocyanin extraction from pomegranate fruit
peel using maceration.
Experiment was carried out in three different parts viz., effect of dehydration in
anthocyanin content, standardization of solvent for anthocyanin extraction and effect of pretreatments to enhance anthocyanin recovery. Uniformly ripe good quality pomegranate fruits
procured from Swasraya Karshaka Vipani of VFPCK, Trivandrum were cleaned by washing,
surface sanitized using 2 ppm ozonised water for 10 minutes, the peel was separated from the
arils and mesocarp, cut into uniform pieces of approximate 2cm3
and utilized for the
experiment.
The prepared peels were subjected to four different dehydration treatments viz., cabinet
drying at 50± 50C for 24 hrs, shade drying for 24 hrs, cabinet drying at 50± 50C for 1 hr
followed by shade drying for 24 hrs and drying in blancher-cum drier at 50± 50C for 24 hrs to
improve the anthocyanin content. Shade drying, cabinet drying followed by shade drying and
cabinet drying of peels had enhanced the anthocyanin content from 6.70 mg/100g to 10.10
mg/100g, 17.37 mg/100g and 55.91 mg/100g respectively. Peels dried in cabinet drier at 50±
5
0C for 24 hrs had 26.15% yield, least moisture content (13.3%), highest total anthocyanin
content (55.91 mg/100g) and comparatively higher total anti-oxidant activity (39.45%); hence
selected as the best dehydration treatment for extraction of anthocyanin content from
pomegranate peel.
In the second part of study, the prepared peel pieces were cabinet dried at 50± 50C for
24 hrs, which was selected as the best dehydration treatment, macerated using three different
solvents viz., acidified ethanol (1% HCl), acidified methanol (1% HCl) and 50% ethanol +
93
0.2% citric acid in 2:1 liquid to solid ratio for 48 hours under room temperature (30-35℃) &
75-80% RH, the infusion mixture was filtered and evaporated under water bath at 60℃ for
complete removal of solvent. Extraction using acidified ethanol with 1 % HCl had recorded
highest yield (25.5%), acidity (5.90%), and anthocyanin content (84.57 mg/100g) along with
comparatively lesser time for extraction (1.50 hr); hence selected as the best solvent for
anthocyanin extraction.
The effect of four different pre-treatment techniques in improving the anthocyanin
extraction efficiency was analysed in the third part of the experiment. Extracts from peel pieces
stored at 4℃ in dark for 24 hrs before cabinet drying and maceration had highest anthocyanin
content (71.35 mg/100g) and total anti-oxidant activity (86.30%) as against 62.51 mg/100g
anthocyanin and 82.33% total anti-oxidant activity in peels without pre-treatment, hence
selected as the best pre-treatment for extracting anthocyanin recovery from pomegranate peels.
Low temperature storage of peel pieces at 4℃ in dark for 24 hrs prior to cabinet drying could
result in 14.14% enhanced anthocyanin recovery.
Extraction conditions to maximize anthocyanin content was optimized by taking into
consideration, the best dehydration method for raw material, solvent suitable for anthocyanin
extraction and adoption of proper pre-treatment prior to extraction procedure. Based on the
results, a protocol was standardized for the efficient extraction of anthocyanin from
pomegranate peels using maceration. Maceration of crushed 2cm3 pomegranate peel pieces,
collected from clean sanitized ripe fruits which are subjected to storage at 4℃ in dark for 24
hrs followed by cabinet drying at 50± 50C for 24 hrs, using acidified ethanol with 1 % HCl in
2:1 liquid to solid ratio for 48 hours under room temperature (30-35℃) & 75-80% RH and
evaporation under water bath at 60℃ could result in enhanced anthocyanin recovery.