Sweet Lemon 2j601d

AKswar Date of Seminar 8.3.2012

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The 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. 2

 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, 4

Outline Aim & Objectives Introduction

Experimental Results & Discussion Conclusion

References

To

prepare

the

pectin-ZnO

Nano

composites and to determine its some properties.

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.

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. Kingdom Order Family Genus Species Botanical name

: : : : : :

Plantae Sapindales Rutaceae Citrus limetta 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.

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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Setting time of pectin Rapid set

:

20-70 s

Medium set

:

70-180 s

Slow set

:

180-250 s

Utilization of pectin Pectin is utilized commercially in the manufacture of various products and the requirements differ for different trades and uses. Certain s require pectin wit a uniformly slow setting rate while a pectin with a rapid setting rate is require for other uses. 10

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)

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Figure 1.

A repeating segment of pectin molecule and functional 12 groups

 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.

 Currently research, hybrid inorganic-organic nano composite materials are great interest for application in the food

industry.

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Preparation of Pectin Powder Prepared material

(citrus peel 100g) Wash with water (thrice) Boil (10 min) dewater Press pulp Boil with HCl (pH =2) at 100°C for 1 hr Pectin extract

Squeeze

Allow to overnight

Cool immediately

Squeeze

Settle and centrifuge

Wash twice with EtOH

Clarified extract Concentrate at 50°C to final volume of 70 % Syrup Added 95 % EtOH with stirring

Dehydrate with acetone Dry in oven (37°C), 5hr

Pectin precipitate powder

Pectin powder (7.85 % yield)

Physico-chemical characterization of prepared pectin

Characterization Moisture Setting time Molecular Weight Reaction with some solvent

Methods Oven dry method Gelling with sugar and acid Viscosity 1) Alcohol 2) Sugar and citric acid solution 3) Fehling’s solution 4) Basic lead acetate solution 5) Iodine solution

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Preparation of Pectin –Zn O nanocomposite Extracted pectin

Zn(NO3)2.6H2O

Distilled water

(0.2g)

(1.2 g)

(40 mL)

Added into 100 mL beaker Stirred to full dissolution Add 0.125 M NaOH (40 mL) under constant stirring

Mixture Stand for 24 h, 20 °C White ppt Washed with distilled water (several time)

Centrifuge & filter Drying at 30 °C for 4 hr Final product

(white powder)

Determination of Setting time

Pectin (0.5 g)

Dissolve in distilled water

by warming

Solution (pH 3)

Poured into the sample glass and timer is started

Pectin solution

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

cool to RT

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

Determination the Size of Pectin-ZnO nanocomposite By Scherrer equation The Scherrer Equation was published in 1918

K B2   L cos

B = FWHM of the observed peak

K = the Scherrer constant L = Crystalline grain size = wavelength of the  wave diffraction   angle of diffration

Intensity (a.u.)

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

FWHM

46.746.846.947.047.147.247.347.447.547.647.747.847.9

2(deg.)

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The Scherrer Constant, K

K B2   L cos

0.94 B2   L cos

• 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 20

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Table 1.

Some physicochemical properties of extracted pectin

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

1) Alcohol

1) White flocculent

solvent

2) Sugar and citric acid solution

precipitate 2) Form jelly

3) Fehling’s solution

3) Blue gel precipitate

4) Basic lead acetate

4) White gelatinous

solution 5) Iodine solution

precipitate 5) Yellow gel 22

Figure 2. Reaction of pectin with some solvent 23

Determination of Average Molecular Weight [] = KMa M = polymer molecular weight K = 0.3 mLg-1 for sodium phosphate buffer A = 0.613

450

400 350

y = 17951x + 175.04 R² = 0.996

Viscosity

300

sp/C ln sp/C

250

200 150 100

y = -2342.5x + 175.62 R² = 0.8447

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M = 3.2528 x 104 Dalton

0 0.0000 0.0020 0.0040 0.0060 0.0080 0.0100 0.0120 0.0140 Concentration (mg/L)

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

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(a)

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

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

Literature value

Assignments

No

Isolated pectin

Commercial pectin

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

1242 1095

1250 1018

1050-1250 1000-1400

C-O stretching

7

1110

1103

1100-1164

O-C-C stretching 26

(a)

(b) Figure 5. FT-IR spectrum of (a) prepare pectin-ZnO composite and (b) commercial pectin-ZnO and (c) reference Reference - Copyright © Nanoscale Res Lett (2008) 3:491-495

(c)

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Table 5. FT-IR data for isolated and commercial pectin-ZnO composite

Wave number (cm-1) Pectin- ZnO Literature value (commercial)

Assignments

No

Pectin – ZnO (isolated)

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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Average ~ 420 nm grain size Figure 6.

SEM microphotograph of Pectin 29

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

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* Figure 8. XRD diffractogram of typical pectin-ZnO composite sample * Copyright © Nanoscale Res Lett (2008) 3:491-495

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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 %).

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 pectinZnO 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.

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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 148 Judeinstein, P., Sanchez.C., (1996), “Preparation and Characterization of InorganicOrganic 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

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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-sweetbenefit-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

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