Canarium Tree: The Tree that Keeps on Giving

The Canarium tree, more commonly known as Elemi and locally known as the Pili tree, is a tree endemic to the Philippines. It is one of the four genera in the family of Burseraceae, with over 100 species of tropical and subtropical trees–and 53 of which have been found in the Philippines. The largest island Luzon is where most of the Canarium species are, particularly in the area called Bicolandia or the Bicol region. In the forests of this region, very old Pili trees measuring more than 50m in height are still to be found today.

My love for Pili started as a child. Our nanny, who hailed from Bicol, would always bring me back some candied Pili kernel snack whenever she comes back to Manila from her yearly vacation. As an aromatherapist, my love for the Canarium tree was enriched in 2018, when I first met a microdistiller here in the Philippines who produces Elemi essential oils from the two primary Canarium species in the Philippines–C. luzonicum and C. ovatum.

The Philippines still dominates the world export market for Pili products. Records of the Department of Agriculture show that the Philippines has been exporting the Elemi resin to the US, Great Britain, France, Germany, Italy, the Netherlands, Cuba, China, Hong Kong, and Japan (Catelo and Jimenez, 2016). While C. luzonicum is sought primarily for its sap or resin, as its essential oil is the international standard preferred in the fragrance industry, the locals of Bicolandia region would much rather give importance to its lesser-known sister, Canarium ovatum, as it bears larger fruit, and therefore is considered to provide more economic value.

The Pili tree is valued by the locals primarily for its nuts or kernel, and the rest of the Pili pulp has long been considered a waste product of the Pili industry. In recent years, the Department of Agriculture identified Pili as a crop worthy of more intensive research and development activities, as the banner crop of Bicolandia (Gallegos et al., 2013). The Pili kernel has the potential of being a top export commodity that is comparable with macadamia, cashew, almond, and walnut in terms of quality. Because of this potential economic gain, various development programs were implemented to assist the Bicol region not just in the production and processing of the Pili nuts, but also diversifying into looking at new ways of processing the Pili resin (Elemi resin), and the production of other Pili-related products from its Pili pulp waste.

Cross Section of a Canarium ovatum Fruit

The Pili kernel or the Pili nut has traditionally been exported by the locals as candied or seasoned snacks like sugar or honey-glazed crispy Pili, Pili tarts, salted Pili, or even roasted Pili.  However, in recent decades, the locals have learned to process the Pili pulp waste into a multitude of products. With this, the Pili fruit alone is currently processed into Pili pulp oil and Pili kernel oil for culinary and cosmetics applications; Pili pulp pomace and Pili kernel pomace as tea; the black peel of the Pili fruit is processed as a natural food coloring for sauces; its raw kernel powder and Pili pulp powder for cakes; the testa or the papery brown seed coating is used as an animal feed or is sometimes roasted and used as an additive for cookies; the shell of the Pili nut is processed into charcoal and when turned into activated carbon, it can be used for water purification. All of these Pili products is apart from the economic value that the Elemi resin alone provides to the industrial sector as an ingredient to manufacture adhesives, printing inks, paints, fireproofing, and waterproofing materials; while the spent resin is sold to varnish manufacturers or up-cycled as a valuable ingredient for aircraft sealant. Further, with the growing number of Filipino micro-distillers and Pili processors in the country, the fresh raw resin is likewise sought to be distilled as C. ovatum essential oil and hydrosol.

The Pili kernel contains approximately 8% carbohydrate, 11.5% to 13.9% protein, and 70% fat. Extraction of the Pili kernel yields a light yellowish oil with a combined linoleic and linolenic fatty acid content of less than 11%, while the saturates－palmitic and stearic acids－account for 33.3% and 10.9% of the fatty acids, respectively. The fatty acid composition of Pili nut oil is similar to palm oil. They both have approximately equal amounts of saturated and unsaturated fatty acids with palmitic and oleic acids as the main fatty acids. The unfractionated oil is very low in polyunsaturated fatty acids. With this, we can say that the Pili kernel oil has poor nutritional value due to its low polyunsaturated fatty acid content (Kakuda et al., 2000).

Some have likened Pili kernel oil to olive oil. The oil has a distinctly sweet taste, which makes it suitable for culinary purposes. Currently, Pili kernel oil is considered an economically-wise substitute for olive oil for local manufacturers of canned sardines, salad dressings, and other food preparations (Pham and Dumandan, 2015).

Physical and Chemical Properties of Olive Oil, Pili Kernel Oil, and Pili Pulp Oil

On the other hand, Pili fruit pulp is slightly richer in fat with approximately 3% carbohydrate, 3% ash, 10% water, 11% protein, and 73% fat. Pili pulp oil is a relatively newly discovered source of vegetable oil in the Philippines. The oil is obtained by manual extraction using a mechanical pulp press, by solvent extraction, or even by enzymatic oil extraction. While the locals would normally use Pili pulp oil as fuel for lighting or used in their daily cooking, most Pili processors in Bicol would market the oil to various nutraceutical cosmetics companies for its applications in soaps and other organic skincare preparations. Currently, Pili pulp oil is traded in both local and international markets as an ingredient in the manufacturing of bath soaps, massage oils, anti-dandruff shampoo, and other cosmetic products.

The Pili pulp oil varies from yellow-green to dark green, depending on the type of extraction. According to Pham and Dumandan, the Pili pulp oil is closer in composition to avocado oil. It is comprised of 56.7% oleic glycerides, 13.5% linoleic glycerides, and 29.3% saturated fatty acids (Catelo and Jimenez, 2016) It has been reported that the Pili pulp oil contains 23.96% palmitic acid, 4.66%  palmitoleic acid, 2.64% stearic acid, 60.93% oleic acid and 6.63% linoleic acid. The lipid molecular species present in the unsaponifiable matter of the said oil are carotenoids (141.79 mg/100 g oil), tocopherols (92.44 mg/100 g oil), and sterols (1,009.61 mg/100 g oil) (Tugay, et al., 2020).

The unsaponifiable matter is higher in Pili pulp oil than in Pili nut oil. With this, the Pili pulp oil is more stable than the Pili nut oil and is considered healthier in terms of its fatty acid composition and natural antioxidant content. Based on the analysis conducted by DOST Region V, the Pili pulp oil has very low free fatty acid (FFA) content (0.06%) and moisture content (0.04%), which favor a long shelf life of the product (Catelo and Jimenez, 2016).

In the last two decades, the C. ovatum tree has given us more than candied Pili nuts and Elemi essential oil. The rising demand for natural ingredients in the pharmaceutical and cosmetics industry has paved the way for the locals to think of ways to process the Pili pulp waste into various agricultural byproducts hence improving the overall Pili product portfolio in the Philippines. Now, we get to enjoy beautiful Pili products like Elemi hydrosol, Pili nut oil, and Pili pulp oil, among others. The steady growth of aromatherapists and increasing consumer awareness of aromatherapy products in the country have likewise been encouraging for the Pili processors to improve their agricultural sustainability practices and Elemi distillation processes to world-class standards. Now that the Canarium ovatum tree or the Pili tree is considered a zero-waste crop, the Pili processors remain optimistic about their roles to provide economic and employment opportunities to their community as they strive to elevate the quality of their products to meet the increasing global demand.

Note: An earlier copy of this article was published in Aromatics in Action™  Vol.5 Issue 3 last September 2022

References:

Asuncion, J.N. (2006). Pili Oil Extraction Technology in DOST-V. DOST-STII. http://sntpost.stii.dost.gov.ph/NewPOST/JanMar2006/Pili_oil_extraction.htmls

Catelo, S. P. and Jimenez, C. D. (2016). An Exploratory Study of the Economic Potential of Philippine Pili Pulp Oil From Waste Pulp.  JEMAD. https://jemad.cem.uplb.edu.ph/articles/an-exploratory-study-of-the-economic-potential-of-philippine-pili-pulp-oil-from-waste-pulp/

Gallegos, R. K. B., Suministrado, D. C., Amongo, R. M. C., and Madlangbayan, M. S. (2013). Some Physical and Mechanical Properties of Pili (Canariumovatum Engl. cv. Katutubo) Nut as a Function of Nut Moisture Content. The Philippine Agricultural Scientist Vol.96 No.1: p66-74.

Kakuda, Y., Jahaniaval, F., Marcone, M. F., Montevirgen, L., Montevirgen, Q., and Umali, J. (2000). Characterization of pili nut (Canarium ovatum) oil: Fatty acid and triacylglycerol composition and physicochemical properties.  J Amer Oil Chem Soc. https://doi.org/10.1007/s11746-000-0156-8

Pham, L. J. and Dumandan N. G. (2015). Philippine Pili: Composition of the lipid molecular species. Journal of Ethnic Foods. https://doi.org/10.1016/j.jef.2015.11.001

Tugay, M.M.D.R., Mopera, L.E., Esguerra, E.B., and Castillo-Israel, K.A.T. (2020). Physico-chemical and quality characterization of pulp oil from two varieties of pili (Canarium ovatum Engl.) from Bicol, Philippines. Food Research. https://doi.org/10.26656/fr.2017.4(6).203 Pham, L. J. and Dumandan N. G. (2020). Bioactive Compounds of Pili (Canarium ovatum Engl.). Bioactive Compounds in Underu