Sweet Lemon

AKswarDate of Seminar 8.3.2012 1 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. 3 pectin-ZnO nanocomposite. The lattice constant obtained from the XRD data are a = 3. FT-IR.  The broadening of the ZnO XRD peaks suggests a nanoscale grain size. particle size. The average particles size was calculated to be 29 nm based on the Scherrer equation. XRD. According to the SEM observation. c = 5. grain size. SEM.209A°). c = 5. 4 . Keyword: Pectin.2050 A°. which are consistent with the reported values for ZnO (a = 3. all the diffraction peaks can be indexed to those hexagonal ZnO. 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.4138 A°.253 A°. Outline Aim & Objectives Introduction Experimental Results & Discussion Conclusion References . To prepare the pectin-ZnO Nano composites and to determine its some properties. . . pectin-ZnO composite by FT-IR. To examine the structure of prepared pectin. 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.Objectives To collect the sample (sweet lemon). 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. Kingdom Order Family Genus Species Botanical name : : : : : : Plantae Sapindales Rutaceae Citrus limetta Citrus limetta 8 . brownish-grey bark The skin of the fruit is light yellow at maturity. the rind is white and about 5 mm thick. and relatively smooth. The pulp is greenish and the juice is sweet rather than acidic. but does need calcium ion 3. Pectic acid  Forms insoluble calcium pectate. Low metnoxyl pectin  Does not need sugar. 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. e. Normal pectin  Gel in the present of acid and sugar 2. This reaction is responsible for the firming effect seen in certain plant tissue. Pectic substances and Gelation 1.g tamatoes 9 . Setting time of pectin Rapid set Medium set Slow set : : : 20-70 s 70-180 s 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. 10 . Certain users require pectin wit a uniformly slow setting rate while a pectin with a rapid setting rate is require for other uses. Apples. grapes. Quince. as protactant of the astrointestinal tract act as immune system stimulate Sources of pectin  Citrus fruits. Guavas. Plums. strawberries (produce large amount of pectin)  Sugger beet. 11 . pumpkin (produce small amount) papaya. Wood-apple. Orange. Cherries. carrot.Health benefits of pectin  Has the potential to lower the serum cholesterol and relief diarrhea  act as detoxicant. A repeating segment of pectin molecule and functional 12 groups .Figure 1.  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. 13 . 14 . 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 Cool immediately Settle and centrifuge Clarified extract Concentrate at 50°C to final volume of 70 % Syrup Added 95 % EtOH with stirring Allow to overnight Squeeze Wash twice with EtOH 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 16 . 2 g) Distilled water (40 mL) Added into 100 mL beaker Stirred to full dissolution Add 0. 20 °C White ppt Washed with distilled water (several time) Centrifuge & filter Drying at 30 °C for 4 hr Final product (white powder) .Preparation of Pectin –Zn O nanocomposite Extracted pectin (0.125 M NaOH (40 mL) under constant stirring Mixture Stand for 24 h.6H2O (1.2g) Zn(NO3)2. 5 g) Dissolve in distilled water Pectin solution by warming cool to RT Solution (pH 3) Poured into the sample glass and timer is started The jelly at the top just congealed.Determination of Setting time Add (1% citric acid Add sugar with solution) a few constant stirring drop. the timer was stop (setting time = 30 minutes) . to get pH = 3 Pectin (0. 9 19 2(deg.247.647.947.447.147.) FWHM 46.347.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 * Peak width (B) is inversely proportional to crystallite size (L) Intensity (a.) .u.846.047.547.746.747.847. K K B2   L cos 0.The Scherrer Constant.08 20 . because 0.94 for FWHM of spherical crystals with cubic symmetry 0. K (the Scherrer constant) depends on the how the width is determined.94 and 0.89 both round up to 1 – K actually varies from 0.94 B2   L cos • The constant of proportionality.89 for integral breadth of spherical crystals w/ cubic symmetry 1.62 to 2. and the size distribution – the most common values for K are: 0. the shape of the crystal. 21 . Table 1.2528 x 104 Da 1) White flocculent precipitate 2) Form jelly 3) Blue gel precipitate 4) Basic lead acetate solution 5) Iodine solution 4) White gelatinous precipitate 5) Yellow gel 22 . Characterization Moisture Some physicochemical properties of extracted pectin Methods Oven dry method Result 20 % Setting time Molecular Weight Reaction with some solvent Gelling with sugar and acid Viscosity 1) Alcohol 2) Sugar and citric acid solution 3) Fehling’s solution 30 minute (slow set) 3. Figure 2. Reaction of pectin with some solvent 23 . 0020 0.0120 0.3 mLg-1 for sodium phosphate buffer 450 A = 0.0000 0. Huggin’s and Kramer’s plot of pectin 24 .04 R² = 0.62 R² = 0.996 400 350 300 Viscosity 250 200 150 100 50 y = -2342.0080 0.0140 Concentration (mg/L) Figure 3.8447 sp/C ln sp/C M = 3.2528 x 104 Dalton 0 0.Determination of Average Molecular Weight [] = KMa M = polymer molecular weight K = 0.0100 0.0040 0.0060 0.5x + 175.613 y = 17951x + 175. (a) (b) Figure 4. FT-IR spectrum of (a) prepare pectin and (b) commercial pectin 25 . FT-IR data of the isolated pectin and commercial pectin Wave number (cm-1) No 1 2 Isolated pectin 3417 2924. 2854 Commercial pectin 3371 2939 Literature value 2500-3600 2855-2960 Assignments O-H stretching C-H stretching 3 4 5 6 7 1743 1651 1450.Table 5.stretching C-H bending C-O stretching O-C-C stretching 26 . 1365 1242 1095 1110 1743 1635 1442-1373 1250 1018 1103 1730-1760 1600-1630 1380 1050-1250 1000-1400 1100-1164 C=O stretching COO. 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) 27 .(a) (b) Figure 5. 1450 1100-1164 1000-1400 C-H stretching C=O stretching COO. FT-IR data for isolated and commercial pectin-ZnO composite Wave number (cm-1) No 1 Pectin – ZnO (isolated) 3325 Pectin.Table 5.ZnO Literature value (commercial) 3380 2500-3600 Assignments O-H stretching 2 3 4 5 6 7 2920 1743 1620 1419 1103 1018 2970.stretching C-H bending O-C-C stretching C-O stretching 8 9 833 478 918 493 920 480 O-H bending ZnO 28 .2870 1749 1627 1380 1103 1018 2850-2960 1730-1760 1600-1630 1380 . Average ~ 420 nm grain size Figure 6. SEM microphotograph of Pectin 29 . Figure 7. XRD diffractogram of commercial and prepare pectin-ZnO composite 30 . XRD diffractogram of typical pectin-ZnO composite sample * Copyright © Nanoscale Res Lett (2008) 3:491-495 31 .* Figure 8. From the overall assessment of the present work. the following inferences may be deduced. From the determination of some physicochemical properties.85 %) from the sweet lemon peel by employing alcohol precipitation method. it was found that molecular weight of citrus pectin is (3.2528 x104) Da and setting time is (30 minute). Pectin has been produced in yield (7. . It has been observed that sweet lemon peel pectin contain moisture content (20 %). 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).(dC-H). 1620 cm-1 (uCOO- ).FT-IR spectral analysis of isolated pectin revealed that absorption 3417 cm-1 due to O-H stretching vibration. The above results indicate that the final product is a true composite of pectin and ZnO. 1419 cm-1 . 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. 2920 cm-1 (uC-H). 33 . 1103 cm-1 (uC-O) were attributed to the characteristic of pectin molecule. Other bands occurring at ~1380 cm-1 was due to C-H bending and 1242.1095 cm-1was due to C-O stretching. 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. The FT-IR spectral data of isolated pectin were closely consistent with the commercial pectin as well as literature value. In typical XRD pattern of the as-prepared sample. all the diffraction peaks can be indexted to those hexagonal ZnO.2050 A°.4138 A°. c = 5. XRD peaks suggests a nanoscale grain size. which are consistent with the reported values for ZnO (a = 3.In the SEM observation. The lattice constant obtained from the XRD data are a = 3. 34 . c = 5.253 A°. the composite granules are irregular and their average composite grain size was about 420 nm.209A°). it can be truly assigned as pectin is inexpensively and abundantly available and be able to bind inorganic substance via molecular interactions. On the basis of these experimental research works. The average particles size was calculated to be 29 nm based on the Scherrer equation. So this approach may find potential application in the food industry. The broadening of the ZnO. USA.. Islamic Azad University. (2006). “Preparation and Characterization of InorganicOrganic Nanocomposite Coatings”.S. University of Wisconsin Madison. Spain 1-35 35 .L. Mangilao..R. (2010). “Preparation of Pectin-ZnO Nanocomposite” Food and Bioprocess Engineering Laboratory.. “Citrus (citrus) and Fortunella (kumquat)” University of Guam.. (2004). Iran 511-525 Manner.C 148 Judeinstein. 1-31 Goyer.Gunasekaran. GU 96923.. 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