Extraction of Edible Leaf Protein Concentrate from Water Hyacinth

Oyeyemi AdeyemiFederal University of Petroleum Resources,

PMB 1221, Effurun. Delta State, Nigeria.

ABSTRACT

• Water hyacinth (Eichhonia crassipes) is one of the aquatic weeds.

• It infests rivers, dams, lakes and irrigation channels on every continent except Antarctica.

• The coverage of water ways by water hyacinth devastates aquatic environment and costs billions of dollars every year as control costs and economic losses.

ABSTRACT

• In these days of diminishing natural resources, it has become necessary to investigate the existing resources in water hyacinth for production of food, food additives, pharmaceuticals and raw materials for agro-allied industries.

• The aim of this study was to convert water hyacinth from an environmental nuisance to a natural resource that is in high demand.

• Edible form of water hyacinth leaf protein concentrate (WHLPC) was extracted.

ABSTRACT

• The physicochemical characteristics, total alkaloids and phenolic compounds of the WHLPC were determined.

• Proximate composition and amino acid profile of the WHLPC were analyzed and the LD50 evaluated.

• The WHLPC was used to formulate feed using different concentrations (7.73, 15.46, 23.19, and 30.92) %w/w.

• A control feed was formulated with soybean (15.46%w/w) in place of WHLPC.

ABSTRACT

• The resulting feeds were fed to different groups of rats over a period of twenty (20) weeks and the growth was monitored.

• Growth response curve of rats placed on formulated feed showed positive slope.

• At the end of the experiment, rats in various groups gained weight, gain in body weight measured in Control rats (55.35 g), WHLPC1 rats (57.75 g) were not significantly different (p>0.05).

• Data revealed that WHLPC is a potential raw material for food and beverages industry.

Study Area

• . The study area (River Ijana) is located within longitude 5.540E and 5.70W and latitude 5.310N and 5.60S as shown in Figure 1.

Figure 1: Map of Warri Showing the Sample Collection Area (River Ijana)

Extraction of WHLPC

• The method described by Wenbiao and Yanling (2010) was modified and used.

• The water hyacinth leaves collected from Ijana River were thoroughly washed in water, and blanched for 5mins with 5% acetic acid, in a heating mantle.

• The leaves were then rinsed in de-ionized water and allowed to dry at room temperature.

Extraction of WHLPC

• Furthermore, the leaves were soaked in 95% ethanol for 6hrs to remove the fat and then dried in an incubator at 45°C to obtain the water hyacinth leaf protein concentrate (WHLPC).

• The now formed water hyacinth leaf protein concentrate (WHLPC) was ground in a Teflon base grinder and stored in an air tight container, for further analysis.

Other methods

• Heavy metal analysis of WHLPC was done with an Atomic Absorption Spectrophotometer (AAS), using the American Public Health association (APHA, 1995) guidelines.

• Concentration total alkaloids of WHLPC was determined by the method described by Harbone (1973).

• The proximate analysis of water hyacinth leaves was carried out according to the method described by AOAC (2005).

Group Corn starch

Protein sources

Soy oil Fish meal Vitamins + Minerals

Control 60 15.46* 8 15.22 1.32WHLPC1 60 7.73 8 22.71 1.32WHLPC2 60 15.46 8 15.22 1.32WHLPC2 60 23.19 8 7.49 1.32WHLPC3 60 30.92 8 0.00 1.32

Table 1: Ingredient composition (%) of the experimental diets

WHLPC – Water hyacinth leaf protein concentrate*Soy protein

Metal Concentration

(mg/kg)

*Upper limit

(mg/kg)

Cd 0.02±0.001 0.05

Cr 0.13±0.001 1.0

Pb 0.001±0.00 0.1

Pt 0.001±0.00 0.1

Pd 0.003±0.001 0.1

Sn 0.001±0.00 0.1

Hg 0.02±0.001 0.05

Table 2: Heavy metal composition of Water hyacinth leaf protein concentrate

Fe 0.001±0.00 5.0

Mn 0.001±0.00 0.05

Cu 0.001±0.00 0.5

Zn 0.001±0.00 24.0

Ni 0.001±0.00 0.5

Co 0.001±0.00 1.0

*Source: WHO (1989)

Nutrient Concentration (%)

Protein 56.38±2.15

Fat 4.11±0.55

Ash 4.88±0.24

Fibre 1.02±0.05

Carbohydrate 33.61±1.55

Table 3: Proximate composition of Water hyacinth leaf protein concentrate

Each value represents mean ± SEM of five determinations.

Amino Acid Concentration (g/100g)

FAO STANDARD (g/100g)

Alanine 3.20±0.15 NAArginine 3.80±0.23 NAAspartic acid 4.96±0.25 NACysteine 0.72±0.01 NAGlutamic acid 6.04±0.52 NAGlycine 3.00±0.12 NAHistidine 1.10±0.09 NAIsoleucine 2.29±0.32 4.2

Table 3.3: Amino Acid composition of Water hyacinth leaf protein concentrate

Leucine 5.01±0.35 4.8

Lysine 3.72±0.48 4.2

Methionine 1.34±0.08 2.2

Phenylalanine 3.67±0.22 2.8

Proline 2.72±0.11 NA

Serine 2.52±0.15 NA

Threonine 2.60±0.17 2.8

Tyrosine 2.20±0.13 2.8

Valine 2.81±0.11 4.2

Each value represents mean ± SEM of five determinations.NA: Not Available

Phytochemical Concentration (mg/kg)

Total alkaloid 16.6±0.2

Phenolic compounds 6.0±0.1

Each value represents mean ± SEM of five determinations.

Table 4: Total Alkaloids and phenolic content of Water hyacinth leaf protein concentrate

Rat ID

Dose

(g/kg.bw)

Short-term

result (48 h)

Long-term

result (12 days)

A 3.25 Survival survival

B 8.37 Survival survival

C 17.51 Survival survival

D 21.50 Survival survival

Table 5: Results of LD50 test of Water hyacinth leaf

protein concentrate

WK0 WK5 WK10 WK15 WK2017

27

37

47

57

67

77

I

II

III

IV

V

Period (Weeks)

Wei

ght (

g)

Figure 2. presents the growth response of rats placed on feed formulated with water hyacinth leaf protein concentrate (WHLPC) over a period of twenty weeks.

CONCLUSION

• Experimental evidence from the present study revealed that;

• Water hyacinth is a good source of leaf protein concentrate

• The water hyacinth leaf protein concentrate (WHLPC) is nutritious as evidenced by proximate composition

CONCLUSION

• WHLPC contains alkaloids and phenolic compounds at physiologic amounts

• WHLPC is not acutely toxic as revealed by the studies on LD50

• WHLPC supports normal growth in rats and compared favourably with soybean

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