Environmental Engineering Reference
In-Depth Information
8.3
Food Source from Red
Seaweeds
seaweed masala;
Gracilaria edulis
as seaweed
pickle, seaweed wafer, and seaweed jelly; and
Ulva lactuca
as seaweed jam (Chennubhotla
et al.
1981
).
Acanthophora
or spiny sea plant,
Asparagopsis
or supreme limu,
Callophyllis
or large wire weed,
Hypnea
or maidenhair,
Halymenia
or red sea
lettuce,
Laurencia
or fl ower limu, and
Scinaia
or tender golden weed are eaten fresh or raw;
chopped and cooked, especially with coconut
milk, or sprinkled as a spice in salads; used to
make pudding and jellies; and dried and rehydrated
in the Pacifi c regions (Novaczek
2001
).
Gracilaria
or sea moss is being used as
homemade agar, garnish for sashimi, used for
commercial agar, or fresh as a salad (Madlener
1977
; Novaczek
2001
).
Gelidiella
or little wire
weed is eaten after being simmered as a jelly in
Japan and Vietnam (Madlener
1977
; Novaczek
2001
; Tanaka and Nakamura
2004
).
Rhodymenia
palmata
or dulse is the most common of edible
seaweeds in Europe and North America.
Alaria
fi stula
,
Chordaria fl agelliformis
, and
Porphyra
umbilicalis
are also used as food, while
Porphyra
or purple lever is being consumed fresh or dried
in Japan, China, Korea, Vietnam, North America,
and Europe (Madlener
1977
; Tanaka and
Nakamura
2004
; Tsutsui et al.
2005
).
Eucheuma
and
Kappaphycus
or thorn grass, elkhorn
(
Eucheuma
), and brown licorice algae tambalang
(
Kappaphycus
) are being eaten with coconut
milk and sugar in Indonesia and Vietnam (Tsutsui
et al.
2005
).
8.5
Production of Vegetable Oils
from Microalgae
Most current research on oil extraction is focused
on microalgae to produce biodiesel from algal
oil. The biodiesel from algal oil in itself is not
signifi cantly different from biodiesel produced
from vegetable oils. Dilution, microemulsifi ca-
tion, pyrolysis, and transesterifi cation are the
four techniques applied to solve the problems
encountered with high fuel viscosity. Of the four
techniques, transesterifi cation of oil into its cor-
responding fatty ester (biodiesel) is the most
promising solution to the high viscosity problem.
This is accomplished by mixing methanol with
sodium hydroxide to make sodium methoxide.
This liquid is then mixed into vegetable oil. The
entire mixture then settles and glycerin is left on
the bottom while methyl esters, or biodiesel, is
left on top. Biodiesel can be washed with soap
and glycerin using a centrifuge and then fi ltered.
Kinematic viscosities of the fatty acid methyl
esters vary from 3.23 to 5.61 mm/s (Knothe
2005
). Methanol is preferred for transesterifi cation
because it is less expensive than ethanol (Graboski
and McCormick
1998
). For production of
biodiesel, macroalga (
Cladophora fracta
) and
microalga (
Chlorella protothecoides
) samples
were used (Demirbas
2008
). The higher heating
value of
Chlorella protothecoides
(25.1 MJ/kg) is
also higher than that of
Cladophora fracta
(21.1 MJ/kg). Most vegetable oils are unsaturated.
The properties of the various individual fatty
esters that comprise biodiesel determine the
overall fuel properties of the biodiesel fuel. The
average polyunsaturated fatty acids of
Chlorella
protothecoides
(62.8 %) are also higher than
those of
Cladophora fracta
(50.9 %). Algae
generally produce a lot of polyunsaturates, which
may present a stability problem since higher
levels of polyunsaturated fatty acids tend to
decrease the stability of biodiesel. However,
8.4
Seaweed Recipes
It is known that about 100,000 tones of seaweeds
are eaten annually in Japan in the name nori, kombu,
and hakama. Seaweeds are rich in proteins,
vitamins, amino acids, growth hormones, miner-
als, and other trace elements. Hypothyroidism
(goiter) can be controlled by the intake of iodine-
rich seaweeds like
Asparagopsis taxiformis
,
Sarconema
spp., etc. Indian seaweed can be best
consumed as follows:
Caulerpa sertularioides
,
Codium
,
Gracilaria confervoides
,
Hydroclathrus
clathratus
,
Laurencia papillosa
, and
Hypnea
valentiae
as seaweed salad;
Ulva lactuca
as
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