Uses and Cultivation of Pili Nut (Pili: An extraordinary nut)

by Junelyn S. de la Rosa

Pili (Canarium ovatum), or the Philippine nut has been called an extraordinary nut. It is food to millions of people from around the world, is delicious and good for the heart and scientists from the University of Guelph, Canada and our Department of Science and Technology (DOST) recently reported that proteins in pili are as important as the proteins found in commercially important oilseeds.

The pili nut

Of the family Burseracea, pili is native to the Philippines and can be found in some parts of the Visayas and Mindanao and in Southern Luzon especially in Sorsogon, Albay, Camarines Sur, in the Bicol region where it is an important crop and source of income of many families. Its local names are: pili, anangi, basiad, liputi, pilaui, and pili-pilauai.

Pili is a shady tree with resinous wood that grows up to 20 meters. It has compound alternate leaves with odd-pinnate leaflets and it bears flower clusters at the tip of its shoots. Pinnate leaves look like a feather with a central axis or stem that has parts branching off it.

Pollination is by insects. Pili bears flowers often which turn to fruits over time. The ovary or the female part of the flower contains three locules or chambers each with two ovules (immature eggs), but most of the time only one ovule develops.

The fruit that develops is a drupe or a stone fruit. A drupe or stone fruit has a thin outer skin, a pulpy middle and a hard stony central part that contains the seed. The fruit is usually 4 to 7 cm long, 2.3 to 3.8 cm in diameter, and weighs 15.7 to 45.7 g.

The skin (exocarp) is smooth, thin, shiny, and turns purplish black as the fruit ripens; the pulp (mesocarp) is fibrous, fleshy, and greenish yellow, and the hard shell (endocarp) within protects a normally dicotyledonous embryo. The basal end of the shell (endocarp) is pointed and the apical end is more or less blunt; between the seed and the hard shell (endocarp) is a thin, brownish, fibrous seed coat developed from the inner layer of the endocarp. This thin coat usually adheres tightly to the shell and/or the seed. Much of the kernel weight is made up of the cotyledons, which are about 4.1 to 16.6% of the whole fruit; it is composed of approximately 8% carbohydrate, 11.5 to 13.9% protein, and 70% fat. Kernels from some trees may be bitter, fibrous or have a turpentine odor.

Its many uses

Pili is a versatile nut being used for a variety of products. The nut kernel is the most important product. It can be eaten raw or roasted where its mild, nutty taste and tender-crispy texture can compare with and even found better than an almond. Pili kernel is also used in chocolate, icecream, and baked goods.

Pili is known for its high oil content which is light-yellow and contains 59.6% oleic glycerides and 38.2% palmitic glycerides which are similar to olive oil. The young shoots and the fruit pulp are edible. The shoots are used in salads, and the pulp is eaten after it is boiled and seasoned. Boiled pili pulp resembles the sweet potato in texture, it is oily (about 12%) and is considered to have food value similar to that of avocado. Pulp oil can be extracted and used for cooking or as a substitute for cottonseed oil in the manufacture of soap and edible products. The stony shells are excellent fuel or growth medium for orchids and ornamental plants.

Testing for protein

To extract the storage proteins from pili, the scientists used the modified Osborne protein fractionation scheme. They only focused on the storage proteins since they are the most abundant proteins in nuts. Results showed that 60.3% of pili's storage proteins are globulins while albumins consist of a very small fraction (2.9%). These results indicated that the proteins in pili are very similar to the proteins in common oilseeds such as soybean, and peanut.

Mature pili nuts used in this test were gathered from Sorsogon in summer 1999. The fruits were first placed in a retting pond to soften the pulp and the nuts were cleaned using a perforated basket flushed with water. Then the nuts were sun-dried and cracked to extract the kernels. Finally the kernels were soaked in warm water, its outer skins removed and the kernels air-dried before they were used for the tests.

Cultivating pili

Pili is a tall, shady tree that grows well in deep, fertile, well-drained soil, warm temperatures, and well distributed rainfall. It cannot tolerate the slightest frost or low temperatures and studies have shown that seeds stored in low temperatures lose their ability to grow or germinate.

There are three pili cultivars grown in the Philippines: katutubo, mayon and oas. Aside from using seeds, they can be cultivated through patch budding or marcotting. A good pili tree can produce 100 to 150 kg of in-shell nuts per harvest. Most of the production in the Philippines are from trees that developed from seedlings and are highly variable in kernel qualities and production. Harvesting is from May to October, peaking in June to August, and requires several pickings. Fruits are de-pulped, cleaned and dried to 3 - 5% moisture content (30C for 27 to 28 h). Nut in shell with a moisture content of 2.5 to 4.6% can be stored in the shade for one year without deterioration of qualities.
Source: Massimo Marcone, Yukio kakuda, Firouz Jahaniaval, and Ricky Yada of the Department of Food Science, Ontario Agricultural College, University of Guelph, Guelph, Ontario, Canada and Lourdes Montevirgen of the Department of Science and Technology (DOST), Bicutan, Taguig, Metro Manila. “Characterization of the proteins of pili nut (Canarium ovatum Engl)” 2003

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