Characterization and functional properties of pectin derived from leaves, pulp and seeds of lady’s finger (Abelmoschus esculentus Moench)
In Malaysia, lady‘s finger also known as okra (Abelmoschus Esculentus Moench) can be easily available all year round with low maintenance cost. In order to overcome issues regarding contamination of pork-related gelatin substance in food products, the development of plant based gelling agent w...
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Format: | Thesis |
Language: | English |
Published: |
2014
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Subjects: | |
Online Access: | http://psasir.upm.edu.my/id/eprint/66628/1/IPPH%202014%204%20IR.pdf |
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Summary: | In Malaysia, lady‘s finger also known as okra (Abelmoschus Esculentus Moench) can
be easily available all year round with low maintenance cost. In order to overcome
issues regarding contamination of pork-related gelatin substance in food products, the
development of plant based gelling agent was encouraged as an alternative to replace
animal gelatin. Based on previous studies, okra plant was indicated as one of the more
promising crops which possess unique properties of a gelling agent. Therefore, this
study aims to extract, characterize the physicochemical and functional properties of
pectin derived from okra leaves, pulp (skin without seeds) and seeds. Pectin was
extracted using a sequential extraction with the applications of hot buffer (HB), hot
buffer with chelating agents (CH), diluted alkali (DA) and concentrated alkali (CA)
soluble solids. The fractions obtained were compared to commercial pectin in terms of
functional group identification using Fourier Transform Infrared Spectroscopy (FTIR),
nutritional composition, monosaccharide composition, pH, melting point, viscosity, gel
strength and functional properties. Optimization of concentration was performed to
determine the optimal concentration for gel formation and subjected to melting point,
viscosity and gel strength analysis. The highest pectin yield was extracted from seeds
with all fractions yield of 86%, followed by the leaves (75%) and pulp (71%). CH
extraction gave the highest yield (>40%) compared to HB and DA from okra leaves,
pulp and seeds. Nutritional composition showed total dietary fibre was the highest in
okra leaves (65.06 ±1. 59) which was significantly different (p < 0.05) from okra pulp
and seeds. HB fraction of leaves, pulp and seeds had highly purified pectin due to high
anhydro uronic acid content and degree of esterification. Gel formation was achieved
when okra pectin was blended together with konjac glucomannan (KG) and stored 16 -
18hr at 4°C ± 1.0 (5.0% of okra pectin: 1.6% of KG). The presence of major functional
groups of pectin lies at 1,300-800 cm-1 in most of the HB, CH and DA fractions of okra
leaves, pulp and seeds. Gel formation was identified by analysing gel strength and
viscosity which showed HB had lower gel strength ( < 15 Bloom grams) than CH
fraction, meanwhile DA fraction exceeds 50 (g) which generally failed to form a gel.
Galacturonic acid and rhamnose were identified in all fractions of okra leaves, pulp and
seeds by using HPLC-RI. Water and oil holding capacities of HB fraction from okra
pulp were higher compared to others, meanwhile DA fractions of okra leaves showed a higher emulsifying ability and better foaming properties than the commercial pectin.
Conclusively, characterization and functional properties of HB, CH and DA fractions
derived from okra leaves, pulp and seeds showed potential use of the plant as gelling
agent. |
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