Please have a look at some of these PDFs...

Please have a look at these PDFs :

extraction of pectin’s from fruits and some starchy vegetables

Pectic substances (pectin and pectinic acid/protopectin) represent a group of compounds, which are carbohydrate derivatives found in the middle lamella of all plant tissues. They are polymers of D-galacturonic acid united by the a-1, 4-glycosidic linkage.

Pectins are water-soluble and when heated in certain ratios with sugar acid form gels. This property is used in the manufacture of fruit jellies, jams, gels, marmalade, candies and the like.

Pectin can be extracted from different sources – orange peel, guava, raw tomato fruits and sweet potato slices by gently heating (simmering) for some times. Pectin from different food sources exhibit different characteristics due to their varying molecular size, structure and degree of esterification.

At constant pH and temperature there is an optimum time for pectin extraction. When heating is continued beyond that time the pectin quality gets degraded. For best results, pectin quality needs to be tested at various intervals during extraction using simple tests. Commercial pectin is manufactured by extraction from apple pulp or orange skin pith as by product of the juice industry. The extract is then heated with salts to precipitate the pectin, which is then washed filtered, dried and packed.

High pectin content fruits: Citrus skins (oranges, tangerines, grapefruit, lemons, limes, etc. - the pectin is high in the skin but low in the fruit), tart cooking apples, crab apples, lemons, wild grapes (Eastern Concord variety), cranberries, gooseberries, boysenberries, sour Apples, Blackberries, Currants, Gooseberries, Loganberries, most Plums (not the Italian kind), and Quinces are high in pectin.

Medium pectin fruits: Ripe Apples, very ripe Blackberries, sour Cherries, Chokecherries, Elderberries, Grapefruit, bottled Grape Juice, (Eastern Concord), Grapes (California), Loquats, Oranges, rhubarb. Low pectin fruits: Apricots, Blueberries, Sweet cherries, sour cherries, Figs, grapefruit, grape juice, grapes (other than wild and Concord types), melons, and oranges, Pears, Plums (Italian), Raspberries, Strawberries

Very Low pectin fruits: Nectarines, peaches, elderberries, grapes (Western Concord variety), guava, and pomegranates. The pectin content in all fruit is also generally higher when fruit is just barely ripe and diminishes as it matures from fully ripe to overripe. The process of ripening involves the breakdown of pectins, which softens the fruit as it ripens. Apples and crabapples (especially unripe ones) are good sources of pectin and are often used in making commercial pectin. Some commercial pectin is made from citrus peels.

Apparatus/Equipments:

v Pan

v Knives

v Spoon/stirrer

v Orange peel/skin

Procedures:

There's LOTs of litterature about pectin from various citrus fruits as it is produced industrially at least since the 1930's. Whaver you do, try and get an historical perspective otherwise you'll just be repeating things that were not decades ago.

Look up people like Kertersz, Deuel, McCready etc.

1. Rouse, A.H., Distribution of pectinesterase and total pectin in component parts of citrus fruits. Food Technology, 1953. 7: p. 360-362.

2. Mccready, R.M. and H.S. Owens, Pectin : A product of citrus waste. Economic Botany, 1954. 8: p. 29-47.

3. Mccready, R.M., Pectic and pectic acid. Extraction of pectin from citrus peels and conversion of pectin to pectic acid., in Methods in Carbohydrate Chemistry, R.L. Whistler, J.N. Bemiller, and M.L. Wolfrom, Editors. 1965. p. 167-170.

4. Zitko, V. and C.T. Bishop, Fractionation of pectins from sunflowers, sugar beets, apples and citrus fruits. Canadian Journal of Chemistry, 1965. 43: p. 3206-3214.

5. Alexander, M.M. and G.A. Sulebele, Characterisation of pectins from Indian citrus peels. Journal of Food Science and Technology, 1980. 17: p. 180-182.

6. Sakai, T. and M. Okushima, Microbial production of pectin from citrus peel. Applied and Environmental Microbiology, 1980. 39(4): p. 908-912.

7. Goto, A., C. Araki, and Y. Izumi, Molecular weight distribution of water soluble pectin in citrus juice. Nippon Shokuhin Kogyo Gakkaishi, 1982. 29(3): p. 155-159.

8. Manabe and Naohara, Studies on the properties and function on pectin in satsuma mandarin fruits (citrus unshiu marc.) part. i. properties of pectin in satsuma. Nippon Shokuhin Kogyo Gakkaishi, 1986. 33(8): p. 602-608.

9. Huong, D.M. and D. Van Luyen, Optimization of pectin extraction from dried peel of citrus grandis. Polymer Bulletin, 1989. 22: p. 599-602.

10. Jae-Kwan, H., Rheological properties of citrus pectin solutions. Korean J. Food Sci. Technol., 1995. 27(5): p. 799-806.

Pectins are usually extracted in hot (about 90°C) acidic conditions (HNO3 is best, pH 1 - 2) for 0.5 h to 3h, depending on the raw material and the propoerties aimed at. Degree of methylation, neutral sugars and mol weight all vary, with impact on gelation properties.

And for a change from acids:

Donaghy, J.A. and A.M. Mckay, Pectin Extraction from Citrus Peel by Polygalacturonase Produced on Whey. Bioresource Technology, 1994. 47(1): p. 25-28.

Contreras-Esquivel J.C., Voget C.E., Vita C.E., Espinoza-Pérez J.D. & Renard C.M.G.C. : Enzymatic extraction of lemon pectin by endo-polygalacturonase from Aspergillus niger. Food Sci Biotechnol 15 (2006) 163-167.

Good luck