chapter ii of nutritional alga,...
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CONTENTS
4.1.4.2.4.3.
AbstractIntroductionMaterialsandMethods
4.3.1.4.3.2.
CollectionandprocessingofseaweedsamplesPhysico‐chemicalpropertiesofG.acerosa
4.3.2.1.4.3.2.2.4.3.2.3.
SwellingcapacityWaterholdingcapacityOilholdingcapacity
4.3.3. ProximatecompositionofG.acerosa
4.3.3.1.4.3.3.2.4.3.3.3.4.3.3.4.4.3.3.5.4.3.3.6.4.3.3.7.
AshcontentTotalfibercontentanalysisProteinextractionfrompowderedseaweedsampleEstimation oftotalproteincontentExtractionofcrudelipidEstimation oftotalcarbohydratecontentAnalysisofmoisturecontent
4.3.4. NutritionalprofileofG.acerosa
4.3.4.1. Prolinecontent4.3.4.2. Estimation ofChlorophyllcontent4.3.4.3. Evaluationofmineralcontentsbyflameatomic
absorptionspectrophotometer4.3.4.4. DeterminationofFattyacidcomposition inG.acerosa4.3.4.5. Aminoacidanalysis4.3.4.6. Vitaminanalysis
4.3.5. Statisticalanalysis
4.4. ResultsandDiscussion
4.4.1. Evaluationofphysico‐chemicalpropertiesofG.acerosa4.4.2. DeterminationofproximatecompositionofG.acerosa4.4.3. AssessmentofmineralcontentofG.acerosa4.4.4. AnalysisoffattyacidcontentofG.acerosa4.4.5. EvaluationofaminoacidconstituentsofG.acerosa4.4.6. DeterminationofvitamincompositionofG.acerosa
4.5. Conclusion 4.6. Summaryoftheresults
Chapter II 88
4.1.ABSTRACT
Seaweeds or marine algae have provided a great biological diversity for
sampling in the phase of drug discovery and development. They are not only significant
sources of essential proteins, vitamins, and minerals, but several species of algae also
produce certain secondary metabolites, polysaccharides and glycoproteins with
excellent bioprotective activities. Hence in the present study, the physico-chemical
properties, proximate composition and nutritional profile of the marine red alga
G. acerosa were evaluated. The results of the analysis of physico-chemical properties
and proximate composition suggest that the seaweed is rich in carbohydrates, protein,
proline, chlorophyll and fiber. Assessment of other nutritional profile of G. acerosa
suggests that the seaweed possess high amount of major (potassium) and trace
elements. Moreover, it is rich in unsaturated fatty acids such as linolenic acid and -
linolenic acid. The amino acid composition of the seaweed was also evaluated and the
results showed the presence of most of the essential amino acids that are required for
the normal functions of the body. The vitamin analysis suggests that the seaweed is rich
in vitamin C and vitamin E (powerful antioxidants). Altogether, the outcome of the
study suggests that the seaweed possess high nutritional value and hence could be used
as an excellent nutritional supplement.
Chapter II 89
4.2.INTRODUCTION
Seaweeds or macroalgae are one of the living renewable resources of the marine
environment with potential food and therapeutic applications (Kumar et al., 2011). For
several decades, these marine algae have been consumed worldwide, particularly in
Asian countries, where they have been used as sources of phycocolloids, thickening and
gelling agents in food industries (Ruperez & Calixto, 2001). These seaweeds are also
found to be rich in essential nutrients such as, proteins, polysaccharides, vitamins and
minerals and they have been considered as an extraordinary source of potassium and
iodine, which are important for metabolic activities (Dhargalkar and Pereira, 2005).
In addition to that, they have become matchless source of chemical compounds that
includes a wide variety of biologically active secondary metabolites (Villarreal-Gómez
et al., 2010). The activity of these bioactive compounds has been linked to good health
for many years, and it appears that bioactive food components can alter the genetic
expression of a host of cellular events, thereby influencing health outcomes or
providing beneficial antioxidant or enzyme inhibitory activities (MacArtain et al.,
2007). Certain seaweeds have been reported to possess potential health benefits
including, hypocholesterolemic activity (Hypnea charoides), normalization of
postprandial glycemia (alginates), when evaluated under in vivo conditions (Brownlee
et al., 2012). Gelidiella acerosa (the seaweed under study) is a tropical alga, and it is a
major source of raw material for the production of superior quality of agar (Prasad et
al., 2007). Although the seaweed G. acerosa have been reported to possess excellent
food value, a detailed analysis of their nutritional composition is not available.
Therefore, in the present study the physicochemical properties, proximate composition,
mineral content, vitamins, fatty acid and amino acid composition of G. acerosa was
investigated.
Chapter II 90
4.3.MATERIALSANDMETHODS
4.3.1.Collectionandprocessingofseaweedsamples
Gelidiella acerosa was collected and processed as mentioned in section 3.3.2.
4.3.2.Physico‐chemicalpropertiesofG.acerosa(Wong&Cheung2000)
4.3.2.1.Swellingcapacity(SWC)
SWC was analyzed by bed volume technique after equilibrating in excess
solvent. 200 mg of seaweed was placed in a container with 20 mL of distilled water and
vigorously stirred. To measure the effect of temperature on SWC, the sample was left to
stand for 24 h in two different temperatures (25ºC and 37ºC). The swelling volume was
measured and expressed as mL of swollen sample per g of sample dry weight (DW).
4.3.2.2.WaterHoldingCapacity(WHC)
WHC was analyzed by modified Centrifugation method. 200 mg of seaweed
sample was placed in 20 mL of distilled water in a centrifugation tube and were kept in
a shaker for 24 h. To determine the effect of temperature on WHC, the samples were
kept at 25ºC and 37ºC.WHC was expressed as weight of gram of water held by 1 g of
dry weight of sample.
4.3.2.3.OilHoldingCapacity(OHC)
The seaweed sample (3 g) was taken in 10.5 g of corn oil in a centrifugation
tube. The tubes were left for 30 min at room temperature with constant agitation. The
mixture was centrifuged at 2500 g for 30 min at room temperature. The oil supernatant
was removed and used for measurement. The OHC of seaweed was measured as the
number of grams of oil held by 1 g of dry weight of sample.
4.3.3.ProximatecompositionofG.acerosa
4.3.3.1.Ashcontent
The freeze dried seaweed sample (5 g) was kept at 525ºC for 5 h in blast furnace
and the ash content was expressed as g of ash obtained per 100 g of sample dry weight.
Chapter II 91
4.3.3.2.Totalfibercontentanalysis
The content of total dietary fiber (TDF) in seaweeds was determined according
to the AOAC enzymatic gravimetric method (AOAC official methods of Analysis;
2005: 962.09).
4.3.3.3.ProteinExtractionfrompowderedseaweedsample
The powdered seaweed (1 g) was introduced into centrifuge tubes containing 50
mL of diethyl ether and water (1:4). The tubes were kept in shaker for 3 h. The
supernatant was discarded and 1N NaOH was added to the sample and kept in shaker
for another 3 h. The mixture was centrifuged at 7000 rpm for 10 min and the
supernatant was collected and precipitated with 10% solution of TCA at pH 4.0. The
samples were kept in ice for 30 min or until visible precipitate appears. The samples
were then centrifuged at 7000 rpm for 20 min. The precipitated protein was washed and
dried.
4.3.3.4.Estimationoftotalproteincontent
Principle
The Lowry’s method (1951) of protein estimation is based on the reduction of
phosphomolybdic acid and phosphotungstic acid by the substances containing phenolic
ring. It results in the formation of blue colored product which is measured at 660 nm.
The amount of color produced varies with proteins as it is based on the proportion of
tyrosine and tryptophan present in it.
Reagents
Bovine serum albumin - 50 mg in 50 mL of d.H2O
Solution A – 2% Na2CO3 in 0.1 N NaOH - 2 g of Na2CO3 was dissolved in 100 mL of 0.1 N NaOH
Solution B – 0.5% CuSO4 in 1% sodium potassium tartarate
- 0.5 g of CuSO4 was dissolved in 100 mL of 1% sodium potassium tartarate
Solution C - 50 mL of Solution A + 1
mL of Solution B
Solution D - Folin-Ciocalteu : Water (1:2)
Chapter II 92
Procedure
The standard and test samples (0.5 mL) was taken in a test tube and made to 2
mL by adding water. BSA was used as standard solution (50 mg/50 mL). 5 mL of
solution C (2% Na2CO3 in 1N NaOH and 0.5% CuSO4 in 1% sodium potassium
tartarate) was added to the tubes and incubated at room temperature for 10 min. Then,
0.5 mL of solution D (Folin’s Ciocalteu reagent 1:2) was added and incubated in dark
for 45 min. The samples were then read at 660 nm in a UV-Vis spectrophotometer.
4.3.3.5.Extractionofcrudelipid
Crude lipids were extracted from the powdered seaweed sample using Soxhlet
apparatus (Wong & Cheung, 2000). The solvent mixture used for extraction is
chloroform and methanol in the ratio of 2:1 (v/v). The contents of the crude lipids were
determined gravimetrically after oven-drying (80ºC) the extract overnight.
4.3.3.6.Analysisofmoisturecontent
Moisture content was determined by moisture analyzer (Karl Fischer oven 860 KF
thermoprep) and expressed as percentage by weight of sample (Wong & Cheung
2000).
4.3.4.NutritionalprofileofG.acerosa
4.3.4.1.Prolinecontent
Principle
The estimation of proline is based on the reaction between proline and
ninhydrin, which forms red colored complex in acidic medium. This complex is soluble
in toluene and thus can be separated from aqueous phase and measured at 520 nm.
Reagents
6 M Phosphoric acid - 19.77 mL of 15.17 M Phosphoric acid was added to d.H2O and made to 50 mL
3% aqueous sulphosalicylic acid - 3 mL in 100 mL of d.H2O
1 M proline - 0.575 g in 5 mL of d. H2O
Procedure
Proline content of the G. acerosa was determined by Bates (1973). About 1.25 g
of ninhydrin was added to 30 mL of glacial acetic acid in a test tube containing 20 mL
Chapter II 93
of 6 M phosphoric acid. The mixture was agitated until it was dissolved and the solution
was kept at 4°C, which is stable for 24 h. 0.5 g of seaweeds were placed in 10 mL of
3% aqueous sulphosalicylic acid and filtered with Whatman no. 1 filter paper. Two mL
of filtrate and 2 mL of acid ninhydrin was mixed with 2 mL of glacial acetic acid. The
mixture was kept at 100°C for 60 min. The reaction was terminated by placing the
mixture in ice bath. After that, the mixture was extracted with toluene, mixed
vigorously with the test tube stirrer. Chromophore containing toluene was collected
from the aqueous phase and warmed at room temperature and the absorbance was
measured at 520 nm using UV-Vis spectrophotometer. Proline was used as standard and
the experiments were done in triplicates.
Calculation
The amount of proline present in the sample can be calculated from the formula
mentioned below:
[(μg proline per mL × Vol. of toluene) / 115.5 μg per μM] / [(g of sample)/5] = μM
proline/g of fresh weight material.
4.3.4.2.EstimationofChlorophyllcontent(Dere,1998)
The seaweed sample of G. acerosa (1 g) was homogenized with 96% methanol
(50 mL for each g) and centrifuged at 1000 rpm for 1 min. The homogenate was then
filtered and centrifuged at 2500 rpm for 10 min. The supernatant was collected and the
absorbance was measured at 400-700 nm in UV-Vis spectrophotometer. The formula
used to calculate chlorophyll A and B content was as follows:
Chlorophyll A = 15.65 (A666)-7.340(A653)
Chlorophyll B = 27.05 (A653)-11.21 (A666)
The amount of chlorophyll obtained was expressed as µg/g of fresh weight.
4.3.4.3.EvaluationofmineralcontentsbyFlameAtomicAbsorptionspectrophotometer(Ruperez2002)
The seaweed (2 g) was taken in a glass container and 10 mL of perchloric acid
was added to it and left without disturbance for 5 min (to remove the organic
constituents present in it). Then, 10 mL of concentrated nitric acid was added to it and
incubated for 5 min and then added with 10 mL of HCl. The mixture was allowed to
evaporate and the final residue was dissolved in 10 mL of concentrated HCl. The
Chapter II 94
filtrate was subjected to analysis in atomic absorption spectrophotometer (Perkin Elmer
Analyst 800 with flame furnace). The minerals analyzed were sodium, potassium,
calcium, iron, magnesium, lead and zinc and the results were expressed as ppm.
4.3.4.4.DeterminationofFattyacidcompositioninG.acerosa
The lipid samples (75 mg) were dissolved in 1 mL of toluene. To the sample
mixture 2 mL of 1% H2SO4 (prepared in methanol) was added and the required esters
were extracted twice with 5 mL of hexane. The hexane layer was separated and was
washed with 4 mL of 2% potassium bicarbonate. The mixture was then dried over
anhydrous Na2SO4 and filtered. The organic solvent was removed in evaporator. The
FAME thus obtained was subjected to Gas Chromatography (Yayli et al., 2001). GC
was performed in 6890N system for GC Agilent Technologies, USA. HP-5 capillary
column was used and it is equipped with Electron impact ionization. Initial temperature
was 70C and then increased to 250C (10C/min) and the injection temperature
employed was 220C. Helium was used as carrier gas at a flow rate of 1 µL/min.
FAME peaks were identified by comparison of their retention times with those of
standard FAME mix (Supelco; Sigma Aldrich).
4.3.4.5.Aminoacidanalysis
Amino acid composition of seaweed sample was determined according to
Gratzfeld- Huesgen (1999). The powdered seaweed samples (2 g) were mixed with
PO4 buffer (pH 7.0) and centrifuged at 3000 rpm for 20 min at 4C. The proteins
present in the supernatant were precipitated separately using 10% TCA. The pellet was
resuspended in 1N NaOH and subjected to acid hydrolysis by incubating with 6N HCl
in boiling water bath for 24 h. The samples were then centrifuged at 3500 rpm for 15
min. The supernatant obtained was filtered and neutralized with 1N NaOH. The filtered
solution was diluted to 1:100 of the volume with milli-Q water and subjected to HPLC
analysis (HP-1101 Agilent technologies with UV and fluorescent detectors).
4.3.4.6.Vitaminanalysis
Vitamin analysis was done for the seaweed G. acerosa. The fat soluble vitamins
analyzed were vitamin A and E using the standards beta carotene and alpha tocopherol
respectively. The seaweed samples after processing were subjected to HPLC analysis
using n-hexane and orthophosphoric acid: methanol in the ratio 95:5 and 0.1 M
potassium acetate (pH 4.9) as mobile phase for vitamin A and E. The liquid
Chapter II 95
chromatograph was equipped with a 254 nm detector and an 8 mm × 10 cm column.
The flow rate was about 2 mL per minute. Retinyl acetate and retinyl palmitate (7.5
µg/mL), α-tocopherol (2 mg/mL) were used as standards for vitamin A and E
respectively. Water soluble vitamins analyzed were vitamin B1, vitamin B2 and vitamin
C using the standards thiamine hydrochloride (10 µg/mL), riboflavin (12 µg/mL) and
ascorbic acid (1 mg/mL) respectively. Vitamin C was analyzed by HPLC method using
acetonitrile-water (50:50) as mobile phase whereas vitamin B1 and B2 were analyzed
spectrophotometrically according to the method of Bradbury and Singh (1986).
4.3.5.Statisticalanalysis
Except for the fatty acid profiles, all analyses were performed in triplicates. All
the data were represented as Mean ± S.D. The statistical analysis was performed using
SPSS software package (Version 17.0). Paired t-test was employed in the evaluation of
physico-chemical properties to compare the data obtained at different temperatures.
P<0.05 were regarded as significant.
4.4.RESULTSANDDISCUSSION
In the present study, the nutritional composition of the marine red alga G.
acerosa was analyzed. Various parameters including physico-chemical properties,
proximate composition, amino acids, vitamins and mineral content of the seaweeds
were evaluated.
4.4.1.Evaluationofphysico‐chemicalpropertiesofG.acerosa
The physico-chemical properties determine the physiological effects of the
dietary fibers. The dietary fiber are resistant to digestion, which provides bulk to feces,
holds water, acts as a site for ion-exchange and binds organic molecules (Ruperez &
Calixto 2001). Centrifugation method was employed to determine the physico-chemical
properties like SWC, WHC and OHC and the results were illustrated in Table 4.1. The
effect of temperature on SWC and WHC were investigated. The SWC and WHC of G.
acerosa was 4 ± 0 mL/g DW and 3.06 ± 0.14 mL/g DW respectively at 25ºC and when
incubated at 37ºC, the values increased slightly to 5 ± 1.4 mL/g DW (SWC) and 3.08 ±
0.14 mL/g DW (WHC) respectively. This increase can be attributed to the increase in
solubility of fibers and proteins. Similarly, oil holding capacity (OHC) is another
important property of food ingredients. The entrapment of oil by capillary attraction is
generally represented as OHC of the seaweeds (Wong & Cheung, 2000). OHC depends
Chapter II 96
on the polar side chains of the amino acids on the surface of their protein molecules.
The OHC of G. acerosa was found to be 0.91 ± 0.02 g/g DW (Table 4.1).
Table 4.1: Physico‐chemical properties of the seaweedG.acerosa
Seaweed SWC (mL/g DW) a WHC (g/g DW) a OHC(g/g DW) a
G. acerosa 25 C 37 C 25 C 37 C
0.91 0.02 4 0 5 1.41 3.06 0.14 3.08 0.14
a Results are expressed as Mean ± SD (n = 3).
4.4.2.DeterminationofproximatecompositionofG.acerosa
The results of proximate composition of G. acerosa were illustrated in
Table 4.2. In general, the ash content represents the total mineral content of the
seaweeds. The ash content of G. acerosa was found to be 0.103 ± 0.04 g/g of DW.
Analysis of dietary fiber content shows that the total dietary fiber content of the
seaweed was 13.45 ± 1.076% DW. Recent studies have demonstrated that the algal
dietary fibers exhibit important functional activities such as antioxidant, anti-mutagenic,
anti-coagulant, anti-tumor activity and a major role in the modification of lipid
metabolism (Tierra 2003). The amount of crude protein content observed was 0.61 ±
0.07 mg/g of DW in G. acerosa. Lipids were the minor components of seaweeds and in
the present study; the total crude lipid content observed was 0.028 ± 0.14 g/g of DW for
G. acerosa. Total carbohydrate content was determined by phenol-sulphuric acid
method and G. acerosa was found to possess 1.05 0.031 g/g DW. Moisture content is
a quality factor in the preservation of some products and affects stability of food
materials and often it is specified in compositional standard (Nielsen, 2010). The
moisture content of G. acerosa was observed as 12.15 ± 0.85%. The extraordinary
nutritional composition of algae in terms of fiber, protein, minerals makes it a nutritive,
low-energy food which represents an important food alternative.
Chapter II 97
Table 4.2: Proximate composition, proline content andchlorophyllcontentofG.acerosa
a Results are expressed as Mean ± SD (n = 3).
In addition to the major nutrient elements, the evaluation of proline and
chlorophyll content has become an important aspect of nutritional profiling. Several
studies have demonstrated that proline elicits stress-stimulated phenolic biosynthesis
and stimulation of antioxidant enzyme response pathways (Shetty 2004). Moreover, at
higher concentrations, chlorophyll possesses excellent antioxidant activity and the
possible mechanism of action behind its antioxidant activity might be either the
protection of linoleic acid against oxidation or prevention of the decomposition of
hydroperoxides (Lanfer-Marquez et al., 2005). Therefore, evaluating the proline and
chlorophyll content of the seaweeds will be an added advantage in the facet of
therapeutics. The proline content of G. acerosa was observed as 83.7 ± 7.4 µmol/g of
DW. Determination of chlorophyll content by spectrophotometric method reveals that
about 1.583 ± 0.049 µg/g Fresh weight (FW) of chlorophyll A and 1.896 ± 0.10 µg/g
FW of chlorophyll B was observed in G. acerosa (Table 4.2).
4.4.3.AssessmentofmineralcontentofG.acerosa
Essential minerals and trace elements required for human nutrition are the major
constituents of seaweeds which range from 8-40% (Ruperez 2002). Since seaweeds are
a rich source of minerals when compared to land plants, the mineral content of G.
acerosa was evaluated in the present study using atomic absorption spectrophotometer.
The results reveal that G. acerosa contain higher amount of Potassium (K) (522.43 ±
22.24 ppm) in it (Table 4.3). Potassium plays an indispensable role in electrical
S. No Composition G. acerosa a
1. Ash content 0.103 0.049 g/g DW
2. Total dietary fiber content 13.45 ± 1.076% DW
3. Crude protein content 0.61 0.07 mg/g DW
4. Crude lipid content 0.028 0.14 g/g DW
5. Moisture content 12.15 ± 0.85%
6. Proline content 83.7 ± 7.4 µmol/g of DW
7. Chlorophyll A 1.583 ± 0.049 µg/g FW
8. Chlorophyll B 1.896 ± 0.10 µg/g FW
Chapter II 98
conductivity of the brain and facilitates the improvement of brain functions. Calcium
was also found to be the abundant mineral in the seaweed, as the concentration was
450.04 ± 24.5 ppm. Recent reports suggest that low levels of Mg contribute to the
heavy metal deposition in the brain that precedes Parkinson’s, Multiple sclerosis and
Alzheimer’s disease. Thus Mg is essential in regulating central nervous system
excitability and normal functions (Murck 2002). The amount of Magnesium (Mg)
present in the seaweed was about 0.203 ± 0.012 ppm (Table 4.3). In addition to these
major elements, marine algae could be an interesting candidate to explore for iron (Fe)
sources, especially in countries where the algal production is feasible (García-Casal et
al., 2009). The amount of Fe present in the seaweed G. acerosa was 1.549 ± 0.10 ppm.
In addition to Fe, G. acerosa was found to possess other elements such as Lead (Pb)
and Zinc (Zn) in the concentrations of 0.001 ± 0.0003 ppm and 0.350 ± 0.028 ppm
respectively (Table 4.3).
Table4.3:MineralcompositionofG.acerosaasdeterminedbyatomicabsorptionspectrophotometer
S. No Name of the element Observed concentration
(ppm) a
1. Sodium 129.05 ± 12.79
2. Potassium 522.43 ± 22.24
3. Calcium 450.04 ± 24.5
4. Iron 1.549 ± 0.10
5. Magnesium 0.203 ± 0.012
6. Lead 0.001 ± 0.0003
7. Zinc 0.350 ± 0.028
a Results are expressed as Mean ± SD (n = 3).
4.4.4.AnalysisoffattyacidcontentofG.acerosa
Fatty acids were found to possess beneficial effects like cardio-protective,
cytotoxic, antimitotic, anticancer, antiviral and anti-mutagenic activities (Prabhakar et
al., 2011; Ortiz et al., 2006). The data on fatty acid composition of G. acerosa is given
in Table 4.4. Total fatty acids present in G. acerosa were found to be 0.5324% (w/w). A
mixture of both saturated and unsaturated fatty acids has been found to be present. The
saturated fatty acids present were palmitic acid (0.1045% w/w), margaric acid
Chapter II 99
(0.0011% w/w) and stearic acid (0.1345% w/w). The unsaturated fatty acids includes
oleic acid (0.0934% w/w), Linolenic acid (0.1034% w/w) and -Linolenic acid
(0.0834% w/w). The results of fatty acid analysis reveal that G. acerosa is rich in
MUFA (Monounsaturated fatty acids) and PUFA (Polyunsaturated fatty acids), which
possess important health benefits. In particular, oleic acid (MUFA) and -linolenic acid
(PUFA) present in the seaweed might help in lowering the blood cholesterol, act as
excellent antioxidants, strengthen cell membrane, repair the damaged cells and tissues,
improve the functioning of heart and fight against cancer.
Table4.4:FattyacidcompositionofG.acerosa
S. No Fatty acids G. acerosa (% w/w)
1. Palmitic acid (16:0) 0.1045
2. Margaric acid (17:0) 0.0011
3. Stearic acid (18:0) 0.1345
4. Oleic acid (18:1) 0.0934
5. Linolenic acid (18:2) 0.1034
6. Alpha linolenic acid (18:3) 0.0834
4.4.5.EvaluationofaminoacidconstituentsofG.acerosa
Quantitative determination of amino acid concentrations was conducted by
HPLC and the results were illustrated in Fig. 4.1. Fourteen amino acids were detected.
Almost all of the essential amino acids including methionine, leucine, lysine,
phenylalanine, tyrosine, arginine, iso-leucine, and valine and five non-essential amino
acids like aspartic acid, glutamic acid, serine, alanine and histidine were found to be
present in G. acerosa. One exception is that among the amino acids, serine, histidine
and threonine was absent (which may be due to undetectable amount present in the
seaweed). Glutamic acid (13.67 ± 0.95 mg/g of protein) and tyrosine (4.12 ± 0.16 mg/g
of protein) was found to be present in higher amount in G. acerosa. Whereas aspartic
acid, alanine, arginine, valine, methionine, phenyl alanine, isoleucine, lysine, leucine
were found to be present at moderate amount of about 1.09 ± 0.087, 1.30 ± 0.07, 2.83 ±
Chapter II 100
0
2
4
6
8
10
12
14
16m
g/g
of p
rote
in
0.25, 1.93 ± 0.11, 2.80 ± 0.16, 1.59 ± 0.11, 0.86 ± 0.06, 2.14 ± 0.17, 1.62 ± 0.08 mg/g
of protein respectively.
Figure 4.1: Amino acid composition of G. acerosa. ThevalueswererepresentedasMean±SD.
4.4.6.DeterminationofvitamincompositionofG.acerosa
Analysis of fat and water soluble vitamins reveals that vitamin C, the major
antioxidant was found to be abundant in G. acerosa, which constitutes to about 5.0718
± 0.202 mg of DW (Table 4.5). The fat soluble vitamins like vitamin A and vitamin E
were analyzed by HPLC methods. Among the fat soluble vitamins, vitamin E was
found to be abundant (next to vitamin C) in G. acerosa, which was about 1.33 ± 0.07
mg/g of DW. Vitamin A constitutes about 0.0034 ± 0.0002 mg DW, whereas Vitamin
B1 and B2 were present only in trace amount.
Table4.5:VitamincompositionofG.acerosa
S. No Vitamins G. acerosa
(mg/g of DW)
1. Vitamin A 0.0034 ± 0.0002
2. Vitamin E 1.33 ± 0.07
3. Vitamin C 5.0718 ± 0.202
4. Vitamin B1 Below detectable level
5. Vitamin B2 Below detectable level
Chapter II 101
4.5.CONCLUSION
The physico-chemical properties, proximate composition and nutritional profile
of the marine red alga G. acerosa, were evaluated. The results of SWC, WHC and OHC
revealed that the seaweed possess high fiber content. The analysis of proximate
composition of G. acerosa suggests that the seaweed possess high amount of proline,
which plays a major role in purine metabolism and oxidative phosphorylation. In
addition to that, the seaweed also contains chlorophyll, which has antioxidant activity.
Evaluation of nutritional profile of G. acerosa shows that it is rich in minerals, fatty
acids, vitamins and amino acids. The minerals are vital players in all the metabolic
reactions. The presence of PUFA and MUFA suggests that the seaweed may exhibit
cardioprotective role. Moreover the seaweed contains most of the essential amino acids
that are required for the normal functions of the body. The presence of vitamin C and
vitamin E suggests that G. acerosa is rich in anitoxidants, which are important to evade
most of the oxidative stress mediated disorders. Hence, the outcome of the study
suggests that G. acerosa has greater nutritional value and could be used as an excellent
nutritional supplement.
Chapter II 102
4.6.SUMMARY