Proximate composition, starch properties and functionality in selected aquatic macrophytes
A total of six freshwater macrophytes, Colocasia esculenta, Eleocharis dulcis, Nelumbo nucifera, Sagittaria sagittifolia, Trapa bispinosa, Typha angustifolia, and one marine macrophyte, Enhalus acoroides were collected and divided into their vegetative (leaf and petiole), reproductive (pollen) an...
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| Format: | Thesis |
| Language: | English |
| Published: |
2019
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/90054/1/FP%202020%2012%20%20ir.pdf |
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| Summary: | A total of six freshwater macrophytes, Colocasia esculenta, Eleocharis dulcis,
Nelumbo nucifera, Sagittaria sagittifolia, Trapa bispinosa, Typha angustifolia,
and one marine macrophyte, Enhalus acoroides were collected and divided into
their vegetative (leaf and petiole), reproductive (pollen) and storage (seed, corm,
rhizome and root) organs. All of these parts were determined for their proximate
composition including moisture, ash, crude lipid, crude fiber, crude protein,
Nitrogen Free Extract (NFE) contents. Proximate analysis showed that leaf part
of freshwater macrophytes had higher moisture (T. angustifolia, 16.24%) and
lipid (C. esculenta, 4.29%), whereas N. nucifera petiole had higher fiber content
(42.60%) compared to others. Also, storage organs of different species had
higher ash (S. sagittifolia root, 25.65%), protein (N. nucifera rhizome, 20.44%)
and NFE (T. bispinosa seed, 72.32%) content. Marine macrophytes, E.
acoroides were observed with higher moisture and ash in root part (18.92% and
27.06% respectively), whereas leaf part displayed higher lipid (2.49%), fiber
(21.66%) and protein (13.58%) contents. The seed of E. acoroides had higher
NFE (59.93%) compared to its leaf (24.73%). Plant parts with high NFE content
(>50%); T. bispinosa seed (72.32%), C. esculenta corm (68.39%), T. angustifolia
pollen (65.62%), N. nucifera seed (63.97%), E. dulcis corm (63.31%), N. nucifera
rhizome (60.21%), E. acoroides seed (59.93%), S. sagittifolia corm (56.16%), E.
acoroides rhizome (55.41%) and T. angustifolia rhizome (51.27%), were
selected and further analyzed in detailed for their starch properties (size, shape
and hilum) and functionality (starch gelatinization, crystallinity and rheological
behavior) by extracting their native starches. Starch granules of aquatic
macrophytes were as simple granules except for C. esculenta corm and
N.nucifera. Size of starch granules from freshwater macrophytes ranged from
smaller granules of T. angustifolia pollen (0.40-4.00 μm) to larger granules of
N. nucifera rhizome (5.00-40.00 μm) whereas, for marine macrophytes, E.
acoroides rhizome starch granules were with bigger size (28.85-53.84 μm) compared to its seed (4.59-28.00 μm). Based on the shapes, polygonal, irregular
and oval were observed in C. esculenta corm and T. angustifolia pollen;
elongated and longitudinal granules in T. bispinosa seed and E. acoroides
rhizome; oval, round and ellipsoidal for the rest of the species. The round and
oval shapes of starch granules were mostly observed with centric hilum whereas
elongated granules had eccentric hilum. Eleocharis dulcis corm starch had
significantly higher total starch content (90.87%) followed by corms of C.
esculenta (82.35%) and S. sagittifolia (71.71%), in which are comparable with
commercial starches. Amylose to amylopectin ratio shows that only N. nucifera
seed categorized as high amylose starch (71.45:28.55%) while N. nucifera
rhizome, T. bispinosa seed, C. esculenta corm and T. angustifolia rhizome as
waxy starch with low amylose content, 7.63%, 8.83%, 10.61% and 13.51%
respectively. On the other hand, parts with higher total starch and amylose
contents were analyzed in E. acoroides rhizome (67.97% and 25.39%
respectively). Non-starch components like protein was high in most starches
(3.06-26.47%) as well as lipid contents (0.24-5.57%) affected the starch purities,
whereas phosphorus contents (0.02-0.43%) association with starch increased
the starch functionality. Glucose was present in all of the samples range between
0.19 g 100 g-1 - 0.25 g 100 g-1. Total sugar contents were comparatively low
ranging from 0.40 g (T. angustifolia rhizome) to 1.71 g (C. esculenta corm)
whereas comparable values were observed in E. acoroides seed (0.63 g) and
rhizome (0.57 g). The functional properties of native starches are important
analysis in order to define its values, whether they are attainable or need some
modification to achieve the desired results. Based on thermal properties, higher
gelatinization temperature on both onset and peak were observed in marine
macrophytes of E. acoroides rhizome (62.35°C and 96.46°C respectively)
whereas lower temperatures were detected in freshwater macrophytes, T.
angustifolia pollen (41.63°C and 74.62°C respectively). High-amylose of N.
nucifera seed and T. angustifolia pollen resulted in higher gelatinization enthalpy
(19.93 and 18.66 Jg-1 respectively) while lower enthalpy was in both E.
acoroides seed (7.72 Jg-1) and rhizome (4.30 Jg-1). In the present study the
lotus seed had higher digestible starch (44.36%) compared to its RS (27.94%).
Higher RS was observed mostly in rhizome part (E. acoroides>N. nucifera>T.
angustifolia) compared to others. Functional properties showed the XRD profiles
of aquatic macrophytes starches displayed that all the corms starches, N.
nucifera seed, and marine macrophytes, E. acoroides seed had A-type
crystallinity. The T. bispinosa seed had CA-type whereas rhizomes part (N.
nucifera and E. acoroides) and T. angustifolia pollen starch exhibited CB-type
crystallinity. Waxy starches of C. esculenta corm had higher relative crystallinity
(36.91%) and viscosity (46.2 mPas) with compared to regular starches. In
conclusion, these selected aquatic macrophytes show its storage organs has
good potential in starch-based food production based on their carbohydrate
content and starch properties. Details on their starch granules properties and
functionality are very important in order to obtain its suitability in food formulation
and non-food application industries. |
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