Sweet Lemon

Preparation and Characterization of

Sweet Lemon Pectin-ZnO Nanocomposites

AKswar

Date of Seminar 8.3.20121

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SUMMARYThe polysaccharide, pectin was extracted from sweet lemon Citrus

limetta Linn.

The yield 7.85 % was obtained from fresh peel of sweet lemon by

acid hydrolysis of protopectin into pectin and followed by alcohol

precipitation method.

Some physicochemical properties, such as moisture (20 % by oven

dry method) and setting time (30 minutes) were observed in isolated

pectin.

The average molecular weight of extracted pectin was found to be

3.2528 x 104 Da by viscosity method.

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The preparation of pectin-ZnO nano composites was carried out in

the aqueous solution condition at room temperature.

The FT-IR spectrum of isolated pectin showed the strong absorption

band at 3417 cm-1 for O-H stretching, 2924 and 2854 cm-1 for C-H

stretching, 1651 cm-1 for COO- stretching, 1743 cm-1 for C=O

stretching, 1450 cm-1 and 1365 cm-1 for C-H bending, 1242 cm-1 and

1095 cm-1 for C-O stretching of alcohol, acid and ether group. All

these absorption bands are agreed with the FT-IR spectrum of

commercial pectin.

The FT-IR spectrum of prepared pectin-ZnO nanocomposites showed

obvious absorption peak at 478 cm-1 for ZnO group together with the

characteristic absorption bands of pectin.

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According to the SEM observation, the composite granules are

irregular and the average composite grain size was about ~ 420 nm

In the typical XRD pattern of the as-prepared composite, all the

diffraction peaks can be indexed to those hexagonal ZnO. The lattice

constant obtained from the XRD data are a = 3.2050 A°, c = 5.4138

A°, which are consistent with the reported values for ZnO (a = 3.253

A°, c = 5.209A°).

The broadening of the ZnO XRD peaks suggests a nanoscale grain

size. The average particles size was calculated to be 29 nm based on

the Scherrer equation.

Keyword: Pectin, pectin-ZnO nanocomposite, FT-IR, SEM, XRD, grain size, particle size,

Aim & Objectives

Introduction

Experimental

Results & Discussion

Conclusion

References

Outline

To prepare the pectin-ZnO Nano

composites and to determine its some

properties.

Aim

Objectives

To collect the sample (sweet lemon).

To extract the pectin to study some physicochemical

properties of isolated pectin.

To convert the prepare pectin to pectin-ZnO

nanocomposite and to study the particle size by SEM

and XRD.

To examine the structure of prepared pectin, pectin-

ZnO composite by FT-IR.

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Citrus limetta is a species of citrus

It is a small tree which may reach 8 m in height

The sweet lemon has irregular branches, and relatively smooth, brownish-grey bark

The skin of the fruit is light yellow at maturity; the rind is white and about 5 mm

thick.

The pulp is greenish and the juice is sweet rather than acidic.

Sweet Lemon (Citrus Limetta Linn)

Kingdom : PlantaeOrder : SapindalesFamily : RutaceaeGenus : CitrusSpecies : limettaBotanical name : Citrus limetta

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Natural, non toxic and amorphous carbohydrate

Gel former eg. fruit jelly

From the Greek word meaning to congeal

Used as gelling substance to make jellies and jams

The important ingredient in cakes and yogust.

Pectin

Pectic substances and Gelation 1. Normal pectin

Gel in the present of acid and sugar

2. Low metnoxyl pectin

Does not need sugar, but does need calcium ion

3. Pectic acid

Forms insoluble calcium pectate. This reaction is responsible for the firming

effect seen in certain plant tissue, e.g tamatoes

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Utilization of pectin

Pectin is utilized commercially in the manufacture of various products and the

requirements differ for different trades and uses. Certain users require pectin wit a

uniformly slow setting rate while a pectin with a rapid setting rate is require for other

uses.

Setting time of pectin

Rapid set : 20-70 s

Medium set : 70-180 s

Slow set : 180-250 s

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Health benefits of pectin

Has the potential to lower the serum cholesterol and relief diarrhea

act as detoxicant, as protactant of the astrointestinal tract act as immune system

stimulate

Sources of pectin Citrus fruits, Apples, Guavas, Quince, Plums, Wood-apple, papaya, Orange,

Cherries, grapes, strawberries (produce large amount of pectin)

Sugger beet, carrot, pumpkin (produce small amount)

12Figure 1. A repeating segment of pectin molecule and functional

groups

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Zinc(Zn) is an essential micronutrient critical for human

health

Its deficiency cause serious and sometimes even disastrous

health problems

ZnO is commonly used to fortify foodstuff in the food

industry

The daily requirement for adult humans is 15–22 mg/day.

ZnO

Currently research, hybrid inorganic-organic nano composite

materials are great interest for application in the food

industry.

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MATERIALS AND METHODS

Preparation of Pectin Powder

Prepared material

(citrus peel 100g)

Press pulp

Pectin extract

Clarified extract

Syrup Pectin precipitatePectin powder

(7.85 % yield)

Wash with water (thrice)

Boil (10 min)

dewater

Boil with HCl (pH =2) at 100°C for 1 hr

Squeeze

Cool immediately

Settle and centrifuge

Concentrate at 50°C to

final volume of 70 %

Added 95 %

EtOH with stirring

Allow to overnight

Squeeze

Wash twice with EtOH

Dehydrate with acetone

Dry in oven (37°C), 5hr

powder

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Physico-chemical characterization of prepared pectin

Characterization MethodsMoisture Oven dry methodSetting time Gelling with sugar and acidMolecular Weight Viscosity Reaction with some solvent 1) Alcohol

2) Sugar and citric acid solution3) Fehling’s solution4) Basic lead acetate solution5) Iodine solution

Preparation of Pectin –Zn O nanocomposite

Extracted pectin

(0.2g)

Zn(NO3)2.6H2O

(1.2 g)

Add 0.125 M NaOH

(40 mL) under constant stirring

Mixture

White ppt

Final product

(white powder)

Added into 100 mL beaker

Stirred to full dissolution

Washed with distilled water (several time)

Centrifuge & filter

Drying at 30 °C for 4 hr

Distilled water

(40 mL)

Stand for 24 h, 20 °C

Pectin (0.5 g) Dissolve in distilled water

by warmingPectin solution

Add sugar with constant stirring

cool to RT

Add (1% citric acid solution) a few drop, to get pH = 3

Solution(pH 3)

Poured into the sample glass and timer is started

The jelly at the top just congealed, the timer was stop(setting time = 30 minutes)

Determination of Setting time

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Determination the Size of Pectin-ZnO nanocomposite By Scherrer equation

cos

2L

KB

The Scherrer Equation was published in 1918

* Peak width (B) is inversely proportional to crystallite size (L)

46.746.846.947.047.147.247.347.447.547.647.747.847.92q (deg.)

Inte

nsity

(a.u

.) FWHM

B = FWHM of the observed peak

K = the Scherrer constant

L = Crystalline grain size

l= wavelength of the l wave diffraction

= q angle of diffration

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The Scherrer Constant, K

• The constant of proportionality, K (the Scherrer constant) depends on the how the

width is determined, the shape of the crystal, and the size distribution

– the most common values for K are:

0.94 for FWHM of spherical crystals with cubic symmetry

0.89 for integral breadth of spherical crystals w/ cubic symmetry

1, because 0.94 and 0.89 both round up to 1

– K actually varies from 0.62 to 2.08

cos

2L

KB

cos

94.02

LB

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RESULTS AND DISCUSSION

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Characterization Methods Result

Moisture Oven dry method 20 %

Setting time Gelling with sugar and acid 30 minute (slow set)

Molecular Weight Viscosity 3.2528 x 104 Da

Reaction with some solvent

1) Alcohol 2) Sugar and citric acid

solution3) Fehling’s solution4) Basic lead acetate

solution5) Iodine solution

1) White flocculent precipitate

2) Form jelly3) Blue gel precipitate4) White gelatinous

precipitate 5) Yellow gel

Table 1. Some physicochemical properties of extracted pectin

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Figure 2. Reaction of pectin with some solvent

24Figure 3. Huggin’s and Kramer’s plot of pectin

Determination of Average Molecular Weight

sp/Cln sp/C

[] = KMa

M = polymer molecular weight

K = 0.3 mLg-1 for sodium phosphate buffer

A = 0.613

M = 3.2528 x 104 Dalton

0.0000 0.0020 0.0040 0.0060 0.0080 0.0100 0.0120 0.01400

50

100

150

200

250

300

350

400

450

f(x) = − 2622.53786458383 x + 177.679877612842R² = 0.96385714470619

f(x) = 17950.6784353742 x + 175.039697777778R² = 0.996008832032369

Concentration (mg/L)

Vis

cosi

ty

25Figure 4. FT-IR spectrum of (a) prepare pectin and (b) commercial pectin

(a)

(b)

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Table 5. FT-IR data of the isolated pectin and commercial pectinWave number (cm-1)

AssignmentsNo Isolated pectin Commercial

pectinLiterature value

1 3417 3371 2500-3600 O-H stretching

2 2924, 2854 2939 2855-2960 C-H stretching

3 1743 1743 1730-1760 C=O stretching

4 1651 1635 1600-1630 COO- stretching

5 1450, 1365 1442-1373 1380 C-H bending

6 12421095

12501018

1050-12501000-1400

C-O stretching

7 1110 1103 1100-1164 O-C-C stretching

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Table 5. FT-IR data for isolated and commercial pectin-ZnO compositeWave number (cm-1)

AssignmentsNo Pectin – ZnO

(isolated)Pectin- ZnO

(commercial)Literature value

1 3325 3380 2500-3600 O-H stretching

2 2920 2970,2870 2850-2960 C-H stretching

3 1743 1749 1730-1760 C=O stretching

4 1620 1627 1600-1630 COO- stretching

5 1419 1380 1380 - 1450 C-H bending

6 1103 1103 1100-1164 O-C-C stretching

7 1018 1018 1000-1400 C-O stretching

8 833 918 920 O-H bending

9 478 493 480 ZnO

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Figure 6. SEM microphotograph of Pectin

Average ~ 420 nm grain size

30Figure 7. XRD diffractogram of commercial and prepare pectin-ZnO composite

CONCLUSION

From the overall assessment of the present work, the following inferences may be

deduced.

Pectin has been produced in yield (7.85 %) from the sweet lemon peel by

employing alcohol precipitation method.

From the determination of some physicochemical properties, it was found that

molecular weight of citrus pectin is (3.2528 x104) Da and setting time is (30

minute).

It has been observed that sweet lemon peel pectin contain moisture content

(20 %).

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FT-IR spectral analysis of isolated pectin revealed that absorption 3417 cm-1 due to

O-H stretching vibration, whereas strong absorption bend observed at 1750 cm-1

and 1600 cm-1 were attributed to the ester carbonyl (C=O) group and carboxyl ion

stretching band (COO-) respectively. Other bands occurring at ~1380 cm-1 was due

to C-H bending and 1242,1095 cm-1was due to C-O stretching.

The FT-IR spectral data of isolated pectin were closely consistent with the

commercial pectin as well as literature value.

FT-IR spectrum of the pectin-ZnO composites prepared from isolated pectin

showed obvious absorption peak at about 478 cm-1, this is a typical IR absorption peak of ZnO. The other bands at 3325 cm-1 (uO-H), 2920 cm-1 (uC-H), 1620 cm-1 (uCOO-),

1419 cm-1 ,(dC-H), 1103 cm-1 (uC-O) were attributed to the characteristic of pectin

molecule.

Furthermore all these FT-IR spectra were found to be very similar to that of pectin-

ZnO composite prepared form commercial pectin and also literature values.

The above results indicate that the final product is a true composite of pectin and

ZnO.

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In the SEM observation, the composite granules are irregular and their average

composite grain size was about 420 nm.

In typical XRD pattern of the as-prepared sample, all the diffraction peaks can be

indexted to those hexagonal ZnO. The lattice constant obtained from the XRD data

are a = 3.2050 A°, c = 5.4138 A°, which are consistent with the reported values for

ZnO (a = 3.253 A°, c = 5.209A°).

The broadening of the ZnO, XRD peaks suggests a nanoscale grain size. The average

particles size was calculated to be 29 nm based on the Scherrer equation.

On the basis of these experimental research works, it can be truly assigned as

pectin is inexpensively and abundantly available and be able to bind inorganic

substance via molecular interactions. So this approach may find potential

application in the food industry.

Gunasekaran, S.L., (2008), “Preparation of Pectin-ZnO Nanocomposite” Food and

Bioprocess Engineering Laboratory, Department of Biological System

Engineering, University of Wisconsin Madison, USA, 1-31

Goyer,Robert., (2004), “Issue Paper on the Human Health Effects of Metals” U.S.

Enviromental Protection Agency Risk Assessment Forum, Washinton D.C

1-48

Judeinstein, P., Sanchez.C., (1996), “Preparation and Characterization of Inorganic-

Organic Nanocomposite Coatings”, Department of Chemistry, Sciences and

Research Branch, Islamic Azad University, Tehran, Iran 511-525

Manner,H.I., Buker,R.S., and Elevitch,C.R., (2006), “Citrus (citrus) and Fortunella

(kumquat)” University of Guam, College of Arts and Sciences, UOG

Station, Mangilao, GU 96923, USA 1-7

Romero, P.G., (2010), “Hybrid Organic-Inorganic Materials”, Institut de Ciencia de

Materials de Barcelona Campus, UAB, Barcelona, Spain 1-35 35

36

Sadjadi, M.S., and Farhadyer, N., (1996), “Preparation and Characterization of

Inorganic-Organic Nanocomposite Coatings”, Department of Chemistry,

Sciences and Research Branch, Islamic Azard University, Tehran, Iran, 1-20

Sharma,B.R., Naresh L., Dhuldhoya,N.C., and Merchant, U.C., (2006), “An Overview

on Pectins” Times Food Processing Journal, Lucid Colloids Limited

Jodhpur-342005, Rajasthan, India 44 -51

World Health Organization (1973) “Guideline on the Specification Limits For Residues

Of Metal Catalysts”, Trace Elements in Human Nutrition: Manganese.

Report of a WHO Expert Committee, Technical Report Service, 532, WHO,

Geneva, Switzerland 34-36

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Clain,J., (2011), “Know sweet Benefits of Sour Lemon”,

http://www.know-sweet-benefit-of-sour-lemon.htm

Colker,C,(2011), “Lemons and Limes:Sweet Enough to eat”

http://www.Lemons&limessweetenoughtoeat-fairwaymarket.htm

Soghoiand,S.,(2010), “Vitamins in Sweet lemon”, http://www.Livestrong.com.htm

ONLINE MATERIALS

http://www.know-sweet-benefit-of-sour-lemon.htm/

http://www/Lemons&limessweetenoughtoeat-fairwaymarket.htm

http://www.livestrong.com.htm/

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THANK YOU

Sweet Lemon

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