LCCA 1:2(2019)82- 88 The Libyan Conference on Chemistry and Its Applications (LCCA 2019) (7 – 9 September, 2019) Chemicalcomposition, physicochemical properties, fatty acid composition and some minerals contents of date kernel from Libya Sultana Hussein1, Salem Abdrba2 and Entisar Nasser1 1Food Technology Dept,, Faculty of Agriculture,Omar Al-Mukhtar University, AL-Bayda – Libya 1- 2Chemistry Dept, Faculty of Science,Omar Al-Mukhtar University, AL-Bayda - Libya A R T I C L E I N F O A B S T R A C T Article history: The purpose of this study was to evaluate the proximate chemical composition, Received 15 July 2019 some chemical characteristics, fatty acid composition and finally, some minerals Revised 15 Augst 2019 for three cultivars of date kernel namely (Saidy Galo, Degla and Baidawy) in Accepted 20 Augst 2019 Libya. The concentrations of proximate chemical composition (%) ranged as Available online 4 July 2020 follows: moisture (4.70-5.50), crude fat (7.70-8.90), crude protein (6.67-7.66), Keywords: ash (0.89-1.09), crude fiber (18.60-20.25), carbohydrates by difference (59.42- Physicochemical, fatty acid, 56.60). The chemical properties of date kernel oils were evaluated as follows: Chemicalcomposition Baidawy cultivar recorded the lowest values for, free fatty acid, iodine value, saponification number and non-saponifiable matter. Saidy Galo cultivar recorded Corresponding author : the highest values for free fatty acid, iodine value and saponification number and [email protected] non-saponifiable number. Gas-liquid chromatographyrevealed that the major unsaturated fatty acids were oleic and linoleic acids, while the major saturated fatty acids were palmitic and myristic acids for all cultivars. We have used flame atomic absorption spectrometry technique for determination of the concentration of some minerals (Na, P, Cu, Mn, Cd , Mg, Pb, Fe and Zn), the results revealed that potassium, magnesium, sodium and phosphorus were the highest minerals content, while the lead and iron were the lowest minerals content in the date kernels. Introduction 2010). The fruit of the date palm is composed of a fleshy pericarp and seed that is usually oblong, ventrally The date palm tree (Phoenix dactylifera L.) is grown grooved, with a small embryo and a hard endosperm. extensively in arid and semiarid regions of the world, Date seeds constitute 10-15% of the date fruit weight. like northern Africa, the Arabian Peninsula and Iran The seed characteristics of date varieties vary according (Ahmed, Al-Gharibi, Daar, &Kabir, 1995). It has always to variety and environmental conditions. Soil played an important part in the economic and social fertilization (Basha and Abo-Hassan, 1982), many lives of the people of these regions. The fruit of the date studies have been carried out on date seeds. These palm is well known as a staple food.Date seeds, also studies have been focused mainly on the chemical called pits, kernels, stones or pips, are a waste product composition of date seeds (El-Rayes, 2009; Ardekani et of date processing and packing plants. Therefore, date al., 2010; Basuni and AL-Marzooq, 2010). Saafi et al. seeds have been a problem to the date industry, while (2008) reported that the seeds of a mixture of some they contain many valuable substances such as mature common date varieties called “Khalti” contained carbohydrates, oil, dietary fiber, protein, bioactive 6.88% moisture, 8.12% total sugars, 6.63% reducing polyphenols and natural antioxidants. However, date sugars, 1.49%. According to Amir Azodi et al. (2014), the seeds can be used for many applications like food seeds of Kabkab and Shahani date varieties from products formulation, cosmetics and functional and Bushehr, Iran consisted of 10.50% moisture, 5.56% of medicinal supplements.Date palm plays an important protein, 12.59% of lipid, 62.18% of soluble fiber in role in the economic and social life of the people in the acidic solutions and finally 1.35% of ash. Also Amany et date producing countries (Basuni and AL-Marzooq, al. (2012) stated that the date seed was composed of 82 LCCA 1:2(2019)82- 88 3.10-7.10% moisture, 2.30-6.40% protein, 5-13.20% fat, Date seeds are reported to contain many minerals such 0.9-1.80% ash and 22.50-80.20% dietary fiber. The as sodium, potassium, magnesium, calcium, phosphorus, differences may be due to the variability of the studied iron, manganese, zinc, copper, nickel, cobalt, chromium, cultivars and also climatic conditions (Saafi et al., 2008). lead and cadmium (Abdillah and Andriani, 2012; Abdul Abdul Afiq et al. (2013) reported that the fat content in Afiq et al., 2013). Potassium,phosphorus, magnesium, date seeds depended on variety, origin, harvesting time calcium and sodium are there in higher concentrations and fertilizer. However, carbohydrate and fat are the in date seeds (Al- Hooti et al., 1998; Devshony et al., main components in date seeds. The protein and fat 1992, Besbes et al., 2004a). Iron and then manganese, content of the date seeds are relatively high in zinc and copper are also found in higher concentrations comparison with the date flesh (1.5-3% for protein and among the microelements (Sawaya et al., 1984). 0.1-1.4% for fat) (Al – Farsi and Lee, 2011). This paper will review some of the characteristics of the Date seeds are a very good source of dietary fiber, which date seed and date seed oil as determine the proximate was reported as 77.8–80.2 g/100 g fresh weight (Al- chemical composition, some chemical characteristics, fatty acid composition and finally, some minerals for Farsi et al., 2007) or 64.5-80.15 g/ 100 g fresh weight three cultivars of date kernel namely (Saidy Galo, Degla (Al-Farsi and Lee, 2011). Abdul Afiq et al., (2013) stated and Baidawy) in Libya. that the total dietary fiber in date seeds was 58%, with 53% of it was insoluble dietary fiber (hemicellulose, Materials and method cellulose and lignin). These differences in dietary fiber are related to maturation stage and variety. The Seed material following average characteristics have been reported for Date palm fruits were purchased from local markets. The kernels of the three cultivars under investigation seed oil of four date cultivars (Zahidi, Medjool, Halawy, (Saidy Galo, Degla and Baidawy) were directly isolated DegletNour): acid value 1.04, iodine value 49.5, from 5 kg of date fruit having the same origin, collected saponification value 221, and unsaponifiable matter at the ‘‘Tamr stage’’ (full ripeness) and kept at 10 ºC for 0.8% (Devshony et al., 1992). The mean of values for the a week. The kernels were soaked in water, washed to seed oil of three Iranian date varieties (Kabkab, Shekar, get rid of any adhering date flesh, and then air-dried. Shahabi) were: peroxide value 1.05 and acid value 1.04. Then, they were further dried at about 50 ºC. Date Besbes et al (2004) also reported that oleic, linoleic, kernels, of each variety, were separately milled in a heavy-duty grinder to pass 1–2 mm screens and then palmitic, myristic and lauric acids together composed preserved at -20 ºC until analyses. 92% of the total fatty acids in the seed oil of Allig and Deglet Noor dates. According to Nehdi et al (2010), oleic Chemical analysis acid composed about 50% of the total fatty acid in P. The moisture content of kernels were determined canariensis seed oil followed by linoleic acid (19.23%), separately by drying a sample (about 5 g) in a drying lauric acid (10.24%) and Palmitic acid (9.83%).The oven at 100 ±5ºC during 24 h. Crude fat, crude protein, crude fiber, crude ash, and values of samples were main fatty acids in Zahidi, Medjool, Halawy, and determined according to the Association of Official DegletNour seed oils were oleic acid (42.3%) and lauric Analytical Chemists (AOAC 2000). Total carbohydrates acid (21.8%), followed by myristic (10.9%), palmitic were calculated by subtracting the total percent values (9.6%) and linoleic acid (13.7%)Devshony et al., 1992. of other measurements from 100. Proximate analyses Walid and Richard (2003) reported that the highest were expressed as grams per 100 g of fresh weight. percentage of unsaturated and saturated fatty acids among the seed oils of 14 date cultivars were oleic acid Oil extraction and preparation: Weights of about 750- 900g of kernels were used for oil extraction. The kernels and lauric acid with amounts of 49.8% and 24.1% in were separated from the fruits, dried and crushed into Suqaey and Rabeaah varieties, respectively. In the case minute granules using automatic machine for 3 m. Total of five date cultivars grown in the United Arab Emirates lipids were extracted from the kernels with hexane (Bushibal, Gash Gaafar, Gash Habash, Luhu, Shahla), the using Soxhlet apparatus. The extraction process fatty acid content of the oils varied from 53.2-58.8% for continued for 4-6 h. The solvent was evaporated on oleic acid, 10.7-12.8% for linoleic acid, 10.6-13.8% for rotary evaporator under reduced pressure and the palmitic acid, 6.3- 10.9% for lauric acid, 5.2-7% for produced oil (free from n-hexane) was collected, weighed, stored in a dark container in a deep-freeze myristic acid, 1.4- 3.7% for stearic acid, 0.1-0.2% for (-20°C) till subsequent analyses. linolenic acid, and 0.5-0.8% for arachidic acid (Al-Hooti et al., 1998). Free fatty acid (as % Oleic acid); Peroxide value (meq. active O2/kg oil), iodine value, saponification number 83 LCCA 1:2(2019)82- 88 and non-saponifiable matter were analyzed according to components i.e.