PhD

An investigation on “Jackfruit (Artocarpus heterophyllus Lam.) as a
potential source of bioactive compounds” was carried out at Department of Post
Harvest Technology, College of Agriculture, Vellayani from 2017-2020 with the
objectives to standardize the extraction procedure for maximizing the antioxidant,
anti-cancerous and anti-hyperglycemic properties of fruit wastes from varikka and
koozha jackfruit types, phytochemical profiling, encapsulation and commercial
exploitation of encapsulated extracts for fortification of fruit juice beverages.
Experiments were carried out in four parts.
Standardization of extraction procedure was carried out in the first part by
evaluating the extracts for antioxidant, anti-hyperglycemic and anti-cancerous
properties. Both varikka and koozha types were harvested at optimum maturity
and were utilized at ripe stage independently. Except bulb, seed and peel without
horny portion, all other parts were dried in cabinet (D1) and freeze (D2) driers,
pulverized to fine powders and extracts were prepared using solvents viz.,
methanol at 90 (S1), 80 (S2), 50% (S3) and ethanol at 60 (S4), 80 % (S5) with solid
to solvent ratios of 1:30 (R1), 1:40 (R2) and 1:50 (R3). Extract of freeze dried
varikka samples using 60 per cent ethanol at 1:50 solid to solvent ratio (D2S4R3)
had highest Total flavonoid content (TFC) (15.66 mg QE 100g-1
), Total phenolic
content (TPC) (156.10 mg GAE 100g), DPPH scavenging activity (69.29 per cent
inhibition) and α-glucosidase inhibition activity (90.24 per cent). The same
extract, D2S4R3 from koozha also exhibited highest TFC (15.88 mg QE 100 g
-1
),
TPC (164.63 mg GAE 100g), DPPH scavenging activity (68.64 per cent
inhibition) and α-glucosidase inhibition activity (92.28 per cent).
Freeze dried varikka samples extracted using 90 per cent methanol at 1:50
solid solvent ratio (D2S1R3) recorded the highest (45.88 mg 100g-1
) ascorbic acid
content and freeze dried koozha samples extracted using 90% methanol at 1:40
solid solvent ratio (D2S1R2) had the highest ascorbic acid content of 47.37 mg
100g-1
.
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Based on the efficiency and economics, extraction of freeze dried samples
using 60% ethanol at 1:40 solid to solvent ratio (D2S4R2), similar samples using
60% ethanol at 1:50 solid to solvent ratio (D2S4R3 ) and cabinet dried samples
with 60% ethanol at 1:50 solid to solvent ratio (D1S4R3) were selected as three
superior extraction methods .
The MTT system which is a simple, reproducible and accurate means of
measuring the activity of living cells via mitochondrial dehydrogenases was
utilized to assess the anti-cancerous properties of the selected three extracts viz.,
D2S4R2, D2S4R3 and D1S4R3 on HeLa cell lines with doxorubicin as control.
Freeze dried varikka and koozha samples extracted in 60 percent ethanol at 1:50
solid to solvent ratio (D2S4R3) had the lowest IC50 value of 129.30 and 157.60 µg
mL-1 respectively whereas the IC50 value for doxorubicin (positive control)
was18.85 µg mL-1
.
When the three superior extracts were subjected to phytochemical profiling in the
second part of the experiment using LCMS/MS (Waters UPLC H class system
fitted with TQD MS/MS system) for sugars, organic acids, phenolic acids and
flavonoids, they were significantly influenced by extraction methods and jack fruit
types. Fifteen sugars, ten organic acids, eighteen phenolic acids and fifteen
flavonoids were fractionated and identified from the extracts. Extract of freeze
dried sample using 60% ethanol in 1:50 solid to solvent ratio (D2S4R3) had highest
sugars, organic acids, phenolic acids and flavonoid content. The major sugars
identified were fructose, glucose, mannose, sucrose and sorbitol and; organic
acids were citric acid, malic acid, shikimic acid, succinic and hydroxycitric acid;
phenolic acids were ferulic acid, p-coumaric acid, caffeic acid, benzoic acid, o -
coumaric acid; myricetin, catechin, naringenin, quercetin and epicatechin were the
major flavonoids.
The three superior extracts selected were encapsulated independently by
spray and freeze drying in the third part of the study. Two maltodextrin (MD)
levels (10 and 20 dextrose equivalence, DE), three carrier to extract ratio (1:10,
1:15 and 1:20), two inlet- outlet temperature of spray drier (180 - 80º C inlet -
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outlet and 190 - 90º C inlet - outlet) were the process variables for spray
encapsulation, whereas for freeze encapsulation, maltodextrin (MD) levels and
carrier ratio were selected as process variables.
The extract D2S4R3 from varikka and koozha, spray encapsulated using
MD 20 DE at 1:20 carrier to extract ratio (Cr3) at inlet and outlet temperature of
180 and 80º C (T1) recorded highest TPC of 115.47 and 117.92 mg GAE 100 g-1
respectively. Varikka and koozha extracts spray encapsulated using MD 20 DE at
1:10 carrier to extract ratio at 190 - 90ºC inlet - outlet temperature (C2Cr1T2)
produced encapsulate with highest per cent recovery (83.77 and 82.09 %
respectively). Lowest moisture content of 2.46 and 2.55 per cent were recorded by
the extracts spray encapsulated using 10 DE MD at 1:20 carrier to extract ratio at
inlet - outlet temperature of 190 - 90º C (C1Cr3T2) from varikka and koozha
respectively. Based on the superior physico-chemical properties, spray
encapsulate of freeze dried varikka and koozha extracts prepared using 60 per cent
ethanol at 1:50 solid to solvent ratio (D2S4R3), using 20 DE maltodextrin at 1:20
carrier to extract ratio with 180 - 80°C inlet - outlet temperature (C2T1Cr3), was
selected for Part 4 of the experiment.
D2S4R3 extract from varikka and koozha, when freeze encapsulated with
MD 20 DE at 1:20 carrier to extract ratio had highest TFC of 11.62 and 11.75 mg
QE 100 g-1
respectively. Koozha extract, freeze encapsulated with MD 20 DE at
1:20 carrier to extract ratio had highest TPC of 134.38 mg GAE 100 g-1 DPPH
scavenging activity of varikka and koozha extracts were highest when freeze
encapsulated with MD 20 DE at 1:20 carrier to extract ratio (per cent inhibition of
71.66 and 77.48 respectively). Ascorbic acid content and per cent recovery of
encapsulates were not influenced by levels of MD or carrier to extract ratio. The
extracts freeze encapsulated with MD 10 DE at 1:10 carrier to extract ratio had
lowest moisture content of 2.22 and 2.51% respectively. Based on the superior
physico-chemical properties, freeze encapsulate of the freeze dried varikka and
koozha extract prepared with 60 per cent ethanol at 1:50 solid to solvent ratio
(D2S4R3), using 20 DE maltodextrin at 1:20 carrier to extract ratio, was selected
for part 4 of the experiment.
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The encapsulated extracts were utilized @ 0.01 to 0.1 per cent for
development of fortified mango RTS beverages as per FSSAI standards and
compared with commercial fortified beverage in the fourth part of study. Mango
RTS beverage enriched with the freeze encapsulate of the extracts @ 0.05 per cent
was found to be superior with respect to Total Soluble Solids, total phenolic
content, antioxidant activity and total sugar content and these were on par with the
beverage enriched with spray encapsulates @ 0.05 per cent and commercial
fortified beverages. The highest TPC of 41.05 and 41.12 mg GAE 100 ml-1 were
recorded in mango RTS beverage enriched with 0.05 per cent freeze encapsulate
of varikka and koozha respectively which were found to be on par with the mango
RTS beverage enriched with 0.05 per cent spray encapsulate. The highest
scavenging activity (76.29 per cent inhibition) was noticed in RTS beverage
enriched with 0.05 per cent freeze encapsulate, followed by the beverage mixed
with 0.05 per cent spray encapsulate (73.21%). The lowest scavenging activity
(55.19 per cent inhibition) was observed in control sample.
From the study, it was proved that the extracts prepared from combined
inedible parts of both varikka and koozha jackfruit types are potential source for
bioactive compounds. Extraction of freeze dried varikka and koozha types using
60 per cent ethanol at 1:50 solid to solvent ratio was standardized as the best
extraction method for retention of phytochemicals, antioxidant activity, antihyperglycemic and anti-cancerous properties. Phytochemical profiling of the
superior extracts revealed the presence of 15 sugars, 10 organic acids, 18 phenolic
acids and 15 flavonoids. Extracts from varikka and koozha spray encapsulated
using 20 DE maltodextrin at 1:20 carrier to extract ratio with 180 - 80°C inlet -
outlet temperature and freeze encapsulated by using 20 DE maltodextrin at 1:20
carrier to extract ratio retained maximum phytochemicals and antioxidant
properties. These spray and freeze encapsulates could be utilized for fortifying
mango RTS beverage @ 50 mg 100 ml-1 without affecting the sensory parameters
with an enhanced antioxidant activity of 13-16% compared to commercial
fortified mango RTS beverage.