Of the 1,300 known food plants, less than 20 are currently used to provide most of our food needs. Since nutraceuticals, described as the vitamins and minerals of the 21st century, represent a new frontier in today’s preventive medicine, it is time to broaden our food base and look for better sources of these plant nutrients.

There is increased public awareness of the health benefits of a diet rich in nutraceuticals and, hence, concentration of nutraceuticals in harvested produce is an important factor to be considered in crop cultivation.

Purslane (Portulaca oleraceae L.), a succulent herb found as a weed throughout the world, has been recently identified as an excellent source of alpha-linolenic acid. Alpha-linolenic is an omega-3 fatty acid, commonly known as fish oil, that plays an important role in human growth, development and disease prevention. This is an essential fatty acid because it can not be synthesized by humans and has to be ingested. Purslane is receiving much attention for cultivation by the United States Department of Agriculture as part of their effort to bring about a modification in the western diet with increased intake of fresh fruits and vegetables.

Culinary and Medicinal Uses

Purslane is widely used as a potherb in Mediterranean, central European and Asian countries. The leaves are, thick, fleshy, palatable, have a mild flavor and a mucilaginous quality. Tender stems and leaves can be eaten raw, alone or with other greens. It can also be cooked or pickled. The leaves of purslane can be frozen or dried and stored in jars for year-round usage.

Purslane, also an excellent source of vitamins A, C and E and the essential amino acids, has been described as a power food of the future because of its high nutritive and antioxidant properties.

Purslane is being used in several parts of the world in the treatment of burns and trauma; headaches; stomach, intestinal and liver ailments; cough; shortness of breath and arthritis. This plant has been employed as a purgative, cardiac tonic, emollient, muscle relaxant, and in anthelmintic, anti-inflammatory and diuretic treatments.

Cultivation

Purslane is an annual succulent with a high growth rate and water use efficiency. Purslane grows well at day/night temperatures of 27/22^oC and long days (16 hours). Because of its high tolerance for different light intensities, temperature ranges and soil types, purslane can be grown in home gardens to provide a steady supply of greens for the kitchen.

The commonly found prostrate weed type is also edible and. forms an effective living mulch in bean and broccoli fields. There are two cultivated types of purslane (golden-leafed and green-leafed) currently available from Johnny’s Selected Seeds (Albion, ME). These cultivated types are upright in habit and about 35.2% richer in their alpha-linolenic acid concentration than the weed type.

Production of Purslane for Optimal Omega-3 Fatty Acid Content

Environmental conditions in which a plant is grown play a key role in the yield and phyto- chemical composition of the harvested produce. A series of studies were conducted at the University of Connecticut under Dr. Richard McAvoy’s direction to identify the environmental conditions that would optimize its leaf alpha-linolenic acid concentration. We grew purslane under a variety of nutritional and environmental regimes in order to identify cultural practices that would optimize the leaf alpha-linolenic acid concentration. Our studies showed that the alpha-linolenic acid concentration was optimized in purslane leaves when the plants were grown under low light intensity, day lengths were 14 to 16 hours, and when 60% of the total nitrogen was supplied in the form of ammonium.

Normally, growing conditions that produce the highest phytochemical concentration in plants do not necessarily produce the highest dry mass yield. When growing purslane in greenhouses during winter (low light intensity and short days), supplemental light can be provided to extend the days. During summer (high light intensity and long days), artificial shading can be adopted to achieve a lower light, intensity in order to optimize the fish oil concentration of the leaves and increase its nutritive value. These practices can increase the fish oil concentration without lowering the yield significantly.

From: Hort Impact. 1998. Volume 98-1 p. 1-2.
By: Usha Palaniswamy, GraduateAssistant, Department of Plant Science, University of Connecticut
Purslane picture from: Emery W. Nelson, University of Nebraska Extension Service, Nebraska Weeds.1979

This information was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

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