18 Journal of Food, Agriculture & Environment, Vol.2 (3&4), August&December 2004 www.world-food.net Journal of Food, Agriculture & Environment Vol.2 (3&4) : 18-20. 2004 WFL Publisher Science and Technology Effect of roasting on the chemical composition of coconut (Cocos nucifera) seed flour and oil I. Adekunle Amoo Chemistry Department, Federal University of Technology, P. M. B. 704 Akure,Ondo State,Nigeria. e-mail:adisamoo@yahoo.co.uk Received 11 June 2004, accepted 28 October 2004. Abstract Freshly harvested coconut was dehusked, grated, roasted, milled and subjected to proximate and mineral analysis using standard methods. The physicochemical properties of oil extracted from it were also determined. Raw coconut seed meal and oil served as control. The following respective percentage proximate values were found for raw and roasted coconut seed flour: total ash 1.71 and 1.86, moisture content 9.71 and 5.19, crude fibre 4.22 and 6.78, crude protein 14.13 and 12.48, crude fat 47.19 and 39.83 and carbohydrate 23.06 and 33.62. The mineral composition (mg/kg) of the raw and roasted coconut seed meal was as follows: sodium 32.9 and 49.3, potassium 228.8 and 515.7, calcium 92 and 104.9, magnesium 178.1 and 436.2, iron 37.9 and 67.8, zinc 43.5 and 119.7, manganese 50.0 and 81.8, phosphorus 184.2 and 750.0. The physicochemical properties of oil from raw and roasted coconut seed gave the following respective values: relative density 0.8193 and 0.8521, refractive index 1.444 and 1.442, acid value 3.90 and 2.95, saponification value 5.43 and 25.52, iodine value 12.11 and 20.01, peroxide value 0.46 and 0.61, free fatty acid 0.20 and 0.16, flash point 6°C and 12°C. The colour of oil from the roasted seed meal was brown while that of raw one was colourless and the odour and taste were pleasant. Roasting significantly influenced the nutrient composition of the meal as well as the physicochemical properties of oil extracted. Key words: Coconut, chemical properties, coconut oil, nutrients. Introduction Coconuts are the fruits of the coconut palm, botanically known as Cocos nucifera meaning “nut-bearing”. The fruit-bearing palms are native to Malaysia, Polynesia and southern Asia and are now also prolific in South America, India, the pacific islands, Hawaii and Florida. The coconut palm was unquestionably spread by Austone Slans through the pacific and eventually to the pacific coast of Central America and westward to India and East Africa. Coconut is an important produce of tropical economy with its enormous range of uses 1 . Palmae, the palm family to which coconut belongs, is one of the oldest and most diverse plant families. Palms have many botanical characters such as woody trunk in many species, perennial growth, leaves which are folded like a fan and the production of single seed leaf which among the grasses, lilies and other families are classified as monocotyledons 2 . Coconuts are by far the most important nuts in the world. They are grown for various purposes in various parts of the world. In the Philippine islands, coconuts are grown as an agricultural and industrial crop. Many of them are consumed locally and export of the various coconut products, such as desiccated coconut, copra, coconut oil and copra meal cake, is major consideration in the national budget and international trade 3 . Coconut is one of the most valuable plants to man. It is a primary source of food, drinks and shelter. The white nutmeat can be eaten raw or shredded, dried and used in most cooking recipes. A single coconut has as much protein as a quarter pound of beefsteak. Copra, the dried meat of the kernels, when crushed is the source of coconut oil. The husks, known as coir is a short coarse elastic fibre used to make an excellent thatch roofing material for houses. It is also an excellent source of charcoal, which finds use as cooking fuel and in the production of gas masks and air filters 1 . The research reported here investigates the effect of roasting, a common traditional process, on the chemical composition of coconut flour and the physicochemical properties of its oil. Materials and Methods The coconut fruits were purchased from Oja-Oba market, Akure, Nigeria. The coconut seeds were mechanically removed from the husk and grated. The grated samples were divided into two portions, one serves as raw sample and the other was roasted to brown colour in a roasting pan to serve as a roasted sample. The two samples were blended into powdery form, kept in an air-tight polythene bag, neatly labeled and stored in a refrigerator at 4°C pending analysis. The proximate and mineral analyses of the samples were carried out as described by AOAC 4 . Phosphorus was determined by the vanadomolybdate method described by Rogert et al. 6 . The crude fat was extracted with petroleum ether (40-60% boiling range) from the dried samples and evaporated as described by Joslyn 5 and carbohydrate concentration was estimated by difference. The acid value and free fatty acids were obtained by dissolving a known amount of the oil in alkaline neutralized mixture of diethyl ether and ethanol. The resulting solution was titrated with standard sodium hydroxide and the titre value obtained was used to calculate the acid value and free fatty acid concentration 7 . To determine the saponification value, a known amount of the oil