Nutritive characterization of purslane accessions as influenced by planting date

The uniqueness of purslane (Portulaca spp.) as the richest vegetable source of omega-3 (omega-3) fatty acids is well documented. However, purslane has not been domesticated or fully evaluated for its nutritive value. The objective of this study was to determine the influence of planting date on chemical composition of purslane accessions. Eight accessions from different geographical locations were planted 12 days apart, and whole plants harvested at full bloom. Chemical analysis (DM basis) of leaves showed significant differences among varieties for all the characteristics measured. Accession by planting date interaction influenced (p <0.05) levels of crude protein, total lipids, and carbohydrate contents. Wild Greek accession had the highest, while a Beltsville (Maryland) wild type had the lowest crude protein content (27.1 vs 20.5%) at the second planting date. Crude protein, lipid and ash levels were most influenced (p <0.05) by planting date. Total lipids varied from 4.0-5.8% and 3.7-5.1% for the first and second planting dates, respectively. Selected fatty acid content indicated significantly (p <0.05) higher levels of 18: 2omega6, and 18: 3omega3 in the Dutch Garden accession compared with other varieties. The Egyptian wild accession had the lowest level of 18: 3omega3. The ratio of omega3 to omega6 acids, which ranged from 5.5 to 22.3 indicated a high nutritive value of purslane compared to other oil crops such as soybeans and perrilla. The high levels of protein in purslane compete with those of other commercially important vegetable crops. The study shows that, in spite of its genetic diversity, purslane remains one of the most abundant terrestrial vegetable sources of Omega-3 fatty acids and other essential nutrients potentially beneficial for humans as well as animals.