Characteristics and chemical composition of date palm (Phoenix canariensis) seeds and seed oil

Abstract

Studies were conducted on properties of seeds and oil extracted from fully ripened Phoenix canariensis date seeds. The percentage composition of the P. canariensis seeds found is: ash 1.18%, oil 10.36%, protein content 5.67%, total carbohydrate 72.59% and moisture 10.20%. The major nutrients (mg/100 g of oil) determined were: potassium (255.43), magnesium (62.78), calcium (48.56) and phosphorus (41.33). The physicochemical properties of the oil observed include: the saponification number 191.28; the iodine number 76.66, the p-anisidine value 3.67; the peroxide value 3.62 meq/kg; the unsaponifiable matter content 1.79%, the free fatty acids content 0.59%; the carotenoid content 5.51 mg/100 g; the chlorophyll content 0.10 mg/100 g and the refractive index 1.45. The main fatty acids of oil were oleic (50.10%), linoleic (19.23%), lauric (10.24%). palmitic (9.83%) and stearic (7.51%). The main triacylglycerols found in P. canariensis seed oil were: LaMM + LaLaP (18.9%), LaMP + MMM (15.31%) and LaOO + PLL + MPL (12.86%). The DSC melting curves revealed that: melting point = 3.71 °C and melting enthalpy = 62.08 J/g. The sterol marker, β-sitosterol, accounted for 76.06% of the total sterols content in the seed oil followed by campesterol (8.89%) and Δ⁵avenesterol (8.79%). α-Tocotrienol was the major tocol (66%) with the rest being γ-tocotrienol and γ-tocopherol.

Introduction

Much attention has recently been focused on the seed oil from different vegetable species such as Moringa oleifera (Lalas and Tsaknis, 2002), hemp (Oomah et al., 2002), prickly pear (Ennouri et al., 2005), Pinus pinea L. (Nasri et al., 2005), Bauhinia purpurea L. (Ramadan et al., 2006), Echinacea (Oomah et al., 2006), Maclura pomifera (Fatnassi et al., 2009), Spartium junceum L. (Cerchiara et al., 2010). Scientists of various specialities invest to highlight their new product and its industrial application as cooking oil or for pharmaceutical and cosmetic purposes and nowadays as bio-fuel sources (Giannelos et al., 2005, Ramadhas et al., 2005).

To our knowledge so far nobody has investigated the potencies of the Phoenix canariensis date seed oil. The mean date seed oils extracted and studied were from different species of the Phoenix Dactylifera genus (Al-Showiman, 1990, Devshony et al., 1992, Al-Shahib and Marshall, 2003, Besbes et al., 2004, Besbes et al., 2005).

Phoenix is the family name of 17 of palm species (canariensis, dactylifera, reclinata, sabal, rupicola,…) (Burnie et al., 2006). It is a member of the palmae family. Its native to the Canary Islands which are located in the Atlantic Ocean off the coast of northeast Africa. These stately palms are popular landscape items in near frost-free climates around the world. This palm is very slow growing when young, yet once the trunk reaches its full diameter the growth rate increases and it fertilizes in spring and summer. It is tolerant to most well drained soils. The P. canariencis is a palm tree which is frequently planted for its ornamental qualities. This palm is best used along boulevards, on campuses and in parks. The mature P. canariensis dates are of red colour and contain a seed nearly 1 cm long. Fruits are not toxic but have an unpleasant taste which renders them unfit for consumption. The use of date pits for animal feed in the traditional way is still likely the most common practice.

The present study is a modest attempt to shed light on the chemical composition of the new oil extracted from the date seed of P. canariensis grown in Tunisia, and to determine its nutritive and industrial uses.