What is pectin?
Pectin refers to a group of diverse and complex polysaccharides found in the primary cell wall and intercellular space (middle lamella) of plant cells. Pectin is mostly composed of a sugar residue called D-galacturonic acid. The dominant polysaccharides in pectin are homogalacturonan, rhamnogalacturonan I, rhamnogalacturonan II, and xylogalacturonan. Pectin is a carbohydrate.
Food sources of pectin
Pectin is present in all plants but the content and composition varies depending on the species, variety, maturity, plant part, tissue, and growing condition. Pectin is higher in legumes and citrus fruits than cereals. Apple, grapefruit, orange and apricot are known to have high levels of pectin. Generally, 60 - 70 percent of the dietary fiber in citrus fruits is pectin. Other sources of pectin include banana, beets, cabbage, carrots etc.
Table 1: List of sample pectin food sources and measurements of their pectin content.
Pectin food source
|
Pectin content (gram/ 100 gram edible weight) |
| Cornflakes |
2.5 |
| Carrot |
0.8 |
| Peach |
0.7 |
| Peas |
0.6 |
| Apple |
0.5 |
| Beans |
0.4 |
| Potato |
0.3 |
Source: Hallowoy et al. (1983).
Health benefits of pectin
Pectin is a soluble dietary fiber and it is reported to have health benefits to humans. Pectin has the potential to lower serum cholesterol, particularly low-density lipoprotein (LDL) Cholesterol, improve insulin resistance, relief diarrhea, and acts as detoxicant, as regulator and protectant of the gastrointestinal tract, as immune system stimulant and as anti-ulcer and antinephrotic agent. Pectin and the other dietary fiber components help prevent a surge in blood glucose levels by promoting satiety, and possibly by reducing the rate of glucose uptake following consumption of glycaemic (available) carbohydrate; therefore it is good for people with diabetes. It is also suggested to reduce heart disease and gallstones.
Several studies have reported significant decrease in serum cholesterol, low density lipoprotein (LDL) cholesterol, and increase or no change in high density lipoprotein (HDL) cholesterol in people administered in their diet with pectin supplement or high pectin sources like fruits (eg. apples) and vegetables (eg. carrots). The benefit of pectin in lowering serum cholesterol may be through its role in increasing fecal cholesterol, fecal fat, sterols or bile acids.
Diets containing pectin incorporated into a food source (eg. citrus fruits) appear to be better tolerated and greater amounts could be consumed than when pure pectin in powder or capsules were consumed.
Uses of pectin in food
Pectin due to its physical and chemical nature, has high water-holding capacity. Because of this property and texture it imparts, pectin is isolated from citrus fruits peel and apple pomace and used as a gelling substances in making jams (eg apple or apricot jams) and thickening foods. Pectin is important ingredient in industrial yogurt, cakes, ketchup, and fruit jelly.
Pharmaceutical/medicinal uses of pectin
Pectin is used in traditional and modern medicine. Traditionally, pectin of panax ginseng is used for its wound healing effects. Also in modern medicine, pectin use in wound bandages is common. Pectin is also an ingriedient in medicines for heart burn, constipation and diarrhea treatments.
References:
Holloway, Warren D, Tasman-Jones, Clifford and Maher, Kerry. 1983. Pectin Digestion in Humans. The Ameican Journal of Clinical Nutrition, 37: 253 - 255.
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